Tailoring cyanobacterial cell factory for improved industrial properties.

Science.gov (United States)

Luan, Guodong; Lu, Xuefeng

Photosynthetic biomanufacturing provides a promising solution for sustainable production of biofuels and biochemicals. Cyanobacteria are among the most promising microbial platforms for the construction of photosynthetic cell factories. Metabolic engineering of cyanobacteria has enabled effective photosynthetic synthesis of diverse natural or non-natural metabolites, while commercialization of photosynthetic biomanufacturing is usually restricted by process and economic feasibilities. In actual outdoor conditions, active cell growth and product synthesis is restricted to narrow light exposure windows of the day-night cycles and is threatened by diverse physical, chemical, and biological environmental stresses. For biomass harvesting and bioproduct recovery, energy and cost consuming processing and equipment is required, which further decreases the economic and environmental competitiveness of the entire process. To facilitate scaled photosynthetic biomanufacturing, lots of efforts have been made to engineer cyanobacterial cell properties required by robust & continual cultivation and convenient & efficient recovery. In this review, we specifically summarized recently reported engineering strategies on optimizing industrial properties of cyanobacterial cells. Through systematically re-editing the metabolism, morphology, mutualism interaction of cyanobacterial chassis cells, the adaptabilities and compatibilities of the cyanobacterial cell factories to the industrial process could be significantly improved. Cell growth and product synthesis of the tailored cyanobacterial cells could be expanded and maintained at night and in stressful environments, while convenient biomass harvesting could also be expected. For developing more feasible cyanobacterial photosynthetic biomanufacturing in large scale, we here propose the importance of tailoring industrial properties of cyanobacteria and outline the directions that should be exploited in the future. Copyright © 2018

Close Link Between Harmful Cyanobacterial Dominance and Associated Bacterioplankton in a Tropical Eutrophic Reservoir

Directory of Open Access Journals (Sweden)

Iame A. Guedes

2018-03-01

Full Text Available Cyanobacteria tend to become the dominant phytoplankton component in eutrophic freshwater environments during warmer seasons. However, general observations of cyanobacterial adaptive advantages in these circumstances are insufficient to explain the prevalence of one species over another in a bloom period, which may be related to particular strategies and interactions with other components of the plankton community. In this study, we present an integrative view of a mixed cyanobacterial bloom occurring during a warm, rainy period in a tropical hydropower reservoir. We used high-throughput sequencing to follow temporal shifts in the dominance of cyanobacterial genera and shifts in the associated heterotrophic bacteria community. The bloom occurred during late spring-summer and included two distinct periods. The first period corresponded to Microcystis aeruginosa complex (MAC dominance with a contribution from Dolichospermum circinale; this pattern coincided with high water retention time and low transparency. The second period corresponded to Cylindrospermopsis raciborskii and Synechococcus spp. dominance, and the reservoir presented lower water retention time and higher water transparency. The major bacterial phyla were primarily Cyanobacteria and Proteobacteria, followed by Actinobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes. Temporal shifts in the dominance of cyanobacterial genera were not only associated with physical features of the water but also with shifts in the associated heterotrophic bacteria. The MAC bloom was associated with a high abundance of Bacteroidetes, particularly Cytophagales. In the second bloom period, Planctomycetes increased in relative abundance, five Planctomycetes OTUs were positively correlated with Synechococcus or C. raciborskii OTUs. Our results suggest specific interactions of the main cyanobacterial genera with certain groups of the heterotrophic bacterial community. Thus, considering biotic

Cyanobacterial diversity and halotolerance in a variable hypersaline environment.

Science.gov (United States)

Kirkwood, Andrea E; Buchheim, Julie A; Buchheim, Mark A; Henley, William J

2008-04-01

The Great Salt Plains (GSP) in north-central Oklahoma, USA is an expansive salt flat (approximately 65 km(2)) that is part of the federally protected Salt Plains National Wildlife Refuge. The GSP serves as an ideal environment to study the microbial diversity of a terrestrial, hypersaline system that experiences wide fluctuations in freshwater influx and diel temperature. Our study assessed cyanobacterial diversity at the GSP by focusing on the taxonomic and physiological diversity of GSP isolates, and the 16S rRNA phylogenetic diversity of isolates and environmental clones from three sites (north, central, and south). Taxonomic diversity of isolates was limited to a few genera (mostly Phormidium and Geitlerinema), but physiological diversity based on halotolerance ranges was strikingly more diverse, even between strains of the same phylotype. The phylogenetic tree revealed diversity that spanned a number of cyanobacterial lineages, although diversity at each site was dominated by only a few phylotypes. Unlike other hypersaline systems, a number of environmental clones from the GSP were members of the heterocystous lineage. Although a number of cyanobacterial isolates were close matches with prevalent environmental clones, it is not certain if these clones reflect the same halotolerance ranges of their matching isolates. This caveat is based on the notable disparities we found between strains of the same phylotype and their inherent halotolerance. Our findings support the hypothesis that variable or poikilotrophic environments promote diversification, and in particular, select for variation in ecotype more than phylotype.

Differential tolerance to cyanobacterial exposure between geographically distinct populations of Perca fluviatilis.

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Persson, Karl-Johan; Bergström, Kristofer; Mazur-Marzec, Hannah; Legrand, Catherine

2013-12-15

Toxic cyanobacterial blooms are an important problem worldwide. Cyanobacteria may negatively impact young-of-the-year (YOY) fish directly (toxin production, turbidity, decrease in water quality) or indirectly (trophic toxin transfer, changes in prey species composition). Here we test whether there are any differences in cyanobacterial tolerance between four geographically distinct populations of European perch (Perca fluviatilis). We show that P. fluviatilis may develop tolerance against cyanobacteria demonstrated by the ability of individuals from a marine site (exposed to annual cyanobacterial blooms) to increase their detoxification more than individuals from an oligotrophic site (rarely exposed to cyanobacteria). Our results also revealed significant interaction effects between genotypes within a population and response to cyanobacterial exposure in terms of absolute growth and detoxification activity. This genotype by treatment interaction may result in local adaptations to cyanobacterial exposure in P. fluviatilis. Hence, the sensitivity against cyanobacterial exposure may differ between within species populations increasing the importance of local management of fish populations. Copyright © 2013 Elsevier Ltd. All rights reserved.

Functional profiling of cyanobacterial genomes and its role in ecological adaptations

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Ratna Prabha

2016-09-01

Full Text Available With the availability of complete genome sequences of many cyanobacterial species, it is becoming feasible to study the broad prospective of the environmental adaptation and the overall changes at transcriptional and translational level in these organisms. In the evolutionary phase, niche-specific competitive forces have resulted in specific features of the cyanobacterial genomes. In this study, functional composition of the 84 different cyanobacterial genomes and their adaptations to different environments was examined by identifying the genomic composition for specific cellular processes, which reflect their genomic functional profile and ecological adaptation. It was identified that among cyanobacterial genomes, metabolic genes have major share over other categories and differentiation of genomic functional profile was observed for the species inhabiting different habitats. The cyanobacteria of freshwater and other habitats accumulate large number of poorly characterized genes. Strain specific functions were also reported in many cyanobacterial members, of which an important feature was the occurrence of phage-related sequences. From this study, it can be speculated that habitat is one of the major factors in giving the shape of functional composition of cyanobacterial genomes towards their ecological adaptations.

First report of cyanobacterial diversity and microcystins in a ...

African Journals Online (AJOL)

The cyanobacterial diversity of Sidi Boughaba, a Moroccan coastal lagoon and Ramsar site, was evaluated and its potentially toxic species were isolated and characterised. This study was the first time that cyanobacterial diversity and cyanotoxin production have been characterised in a Moroccan coastal lagoon. Samples ...

Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

Science.gov (United States)

Piontek, Marlena; Czyżewska, Wanda

2017-03-01

The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River (including Sławskie lake which is the beginning of the river), which is a source of drinking water for the inhabitants of Zielona Góra. In order to evaluate toxicity of cyanobacterial bloom it was conducted toxicological testing using aquatic invertebrates (Daphnia magna, Dugesia tigrina) and heterotrophic bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescens). Test samples were collected from May to October, 2012. The most toxic was a sample collected from Lake Sławskie on 20th October when cyanobacteria bloom with a predominance of Microcystis aeruginosa occurred and the amount of microcystins was the largest. The methanol extract of the sample was toxic only above a concentration of 6·103 mg·dm-3. The lethal concentration (48-h LC 50) for Daphnia magna was 3.09·103 and for Dugesia tigrina (240-h LC 50) 1.51·103 mg·dm-3 of microcystins (MC-LR, MC-YR and MC-RR). The same extract stimulated growth of Escherichia coli and Enterococcus faecalis cells.

Transcriptional and posttranscriptional regulation of cyanobacterial photosynthesis.

Science.gov (United States)

Wilde, Annegret; Hihara, Yukako

2016-03-01

Cyanobacteria are well established model organisms for the study of oxygenic photosynthesis, nitrogen metabolism, toxin biosynthesis, and salt acclimation. However, in comparison to other model bacteria little is known about regulatory networks, which allow cyanobacteria to acclimate to changing environmental conditions. The current work has begun to illuminate how transcription factors modulate expression of different photosynthetic regulons. During the past few years, the research on other regulatory principles like RNA-based regulation showed the importance of non-protein regulators for bacterial lifestyle. Investigations on modulation of photosynthetic components should elucidate the contributions of all factors within the context of a larger regulatory network. Here, we focus on regulation of photosynthetic processes including transcriptional and posttranscriptional mechanisms, citing examples from a limited number of cyanobacterial species. Though, the general idea holds true for most species, important differences exist between various organisms, illustrating diversity of acclimation strategies in the very heterogeneous cyanobacterial clade. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux. Copyright © 2015 Elsevier B.V. All rights reserved.

Cyanobacterial Occurrence and Diversity in Seagrass Meadows in ...

African Journals Online (AJOL)

Oscillatoria, Lyngbya and Spirulina were the dominant cyanobacterial genera. Cyanobacterial coverage was higher in Mjimwema (31–100%) than in Ocean Road (0–60%). The levels of nutrients in tidal pool waters at Ocean Road ranged from 0.45–1.03 μmol NO3 -N/l, 0.19–0.27 μmol NO2 -N/l and 0.03–0.09 μmol PO4 ...

Engineering Cyanobacterial Cell Morphology for Enhanced Recovery and Processing of Biomass.

Science.gov (United States)

Jordan, Adam; Chandler, Jenna; MacCready, Joshua S; Huang, Jingcheng; Osteryoung, Katherine W; Ducat, Daniel C

2017-05-01

Cyanobacteria are emerging as alternative crop species for the production of fuels, chemicals, and biomass. Yet, the success of these microbes depends on the development of cost-effective technologies that permit scaled cultivation and cell harvesting. Here, we investigate the feasibility of engineering cell morphology to improve biomass recovery and decrease energetic costs associated with lysing cyanobacterial cells. Specifically, we modify the levels of Min system proteins in Synechococcus elongatus PCC 7942. The Min system has established functions in controlling cell division by regulating the assembly of FtsZ, a tubulin-like protein required for defining the bacterial division plane. We show that altering the expression of two FtsZ-regulatory proteins, MinC and Cdv3, enables control over cell morphology by disrupting FtsZ localization and cell division without preventing continued cell growth. By varying the expression of these proteins, we can tune the lengths of cyanobacterial cells across a broad dynamic range, anywhere from an ∼20% increased length (relative to the wild type) to near-millimeter lengths. Highly elongated cells exhibit increased rates of sedimentation under low centrifugal forces or by gravity-assisted settling. Furthermore, hyperelongated cells are also more susceptible to lysis through the application of mild physical stress. Collectively, these results demonstrate a novel approach toward decreasing harvesting and processing costs associated with mass cyanobacterial cultivation by altering morphology at the cellular level. IMPORTANCE We show that the cell length of a model cyanobacterial species can be programmed by rationally manipulating the expression of protein factors that suppress cell division. In some instances, we can increase the size of these cells to near-millimeter lengths with this approach. The resulting elongated cells have favorable properties with regard to cell harvesting and lysis. Furthermore, cells treated in this

Controls on O2 Production in Cyanobacterial Mats and Implications for Earth's Oxygenation

Science.gov (United States)

Dick, Gregory J.; Grim, Sharon L.; Klatt, Judith M.

2018-05-01

Cyanobacterial mats are widely assumed to have been globally significant hot spots of biogeochemistry and evolution during the Archean and Proterozoic, but little is known about their quantitative contributions to global primary productivity or Earth's oxygenation. Modern systems show that mat biogeochemistry is the outcome of concerted activities and intimate interactions between various microbial metabolisms. Emerging knowledge of the regulation of oxygenic and sulfide-driven anoxygenic photosynthesis by versatile cyanobacteria, and their interactions with sulfur-oxidizing bacteria and sulfate-reducing bacteria, highlights how ecological and geochemical processes can control O2 production in cyanobacterial mats in unexpected ways. This review explores such biological controls on O2 production. We argue that the intertwined effects of light availability, redox geochemistry, regulation and competition of microbial metabolisms, and biogeochemical feedbacks result in emergent properties of cyanobacterial mat communities that are all critical yet largely overlooked mechanisms to potentially explain the protracted nature of Earth's oxygenation.

A novel earth observation based ecological indicator for cyanobacterial blooms

Science.gov (United States)

Anttila, Saku; Fleming-Lehtinen, Vivi; Attila, Jenni; Junttila, Sofia; Alasalmi, Hanna; Hällfors, Heidi; Kervinen, Mikko; Koponen, Sampsa

2018-02-01

Cyanobacteria form spectacular mass occurrences almost annually in the Baltic Sea. These harmful algal blooms are the most visible consequences of marine eutrophication, driven by a surplus of nutrients from anthropogenic sources and internal processes of the ecosystem. We present a novel Cyanobacterial Bloom Indicator (CyaBI) targeted for the ecosystem assessment of eutrophication in marine areas. The method measures the current cyanobacterial bloom situation (an average condition of recent 5 years) and compares this to the estimated target level for 'good environmental status' (GES). The current status is derived with an index combining indicative bloom event variables. As such we used seasonal information from the duration, volume and severity of algal blooms derived from earth observation (EO) data. The target level for GES was set by using a remote sensing based data set named Fraction with Cyanobacterial Accumulations (FCA; Kahru & Elmgren, 2014) covering years 1979-2014. Here a shift-detection algorithm for time series was applied to detect time-periods in the FCA data where the level of blooms remained low several consecutive years. The average conditions from these time periods were transformed into respective CyaBI target values to represent target level for GES. The indicator is shown to pass the three critical factors set for marine indicator development, namely it measures the current status accurately, the target setting can be scientifically proven and it can be connected to the ecosystem management goal. An advantage of the CyaBI method is that it's not restricted to the data used in the development work, but can be complemented, or fully applied, by using different types of data sources providing information on cyanobacterial accumulations.

Influence of Cyanobacterial Bloom on Freshwater Biocoenosis. Use of Bioassays for Cyanobacterial Microcystins Toxicity Assessment

Directory of Open Access Journals (Sweden)

Piontek Marlena

2017-03-01

Full Text Available The issues presented in this study concern a very important problem of the occurrence of cyanobacterial blooms in surface water used for water supply purposes. The objective of this study was to analyze the occurrence of cyanotoxic risk in the catchment area of the Obrzyca River (including Sławskie lake which is the beginning of the river, which is a source of drinking water for the inhabitants of Zielona Góra. In order to evaluate toxicity of cyanobacterial bloom it was conducted toxicological testing using aquatic invertebrates (Daphnia magna, Dugesia tigrina and heterotrophic bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas fluorescens. Test samples were collected from May to October, 2012. The most toxic was a sample collected from Lake Sławskie on 20th October when cyanobacteria bloom with a predominance of Microcystis aeruginosa occurred and the amount of microcystins was the largest. The methanol extract of the sample was toxic only above a concentration of 6·103 mg·dm-3. The lethal concentration (48-h LC 50 for Daphnia magna was 3.09·103 and for Dugesia tigrina (240-h LC 50 1.51·103 mg·dm-3 of microcystins (MC-LR, MC-YR and MC-RR. The same extract stimulated growth of Escherichia coli and Enterococcus faecalis cells.

MODIS observations of cyanobacterial risks in a eutrophic lake: Implications for long-term safety evaluation in drinking-water source.

Science.gov (United States)

Duan, Hongtao; Tao, Min; Loiselle, Steven Arthur; Zhao, Wei; Cao, Zhigang; Ma, Ronghua; Tang, Xiaoxian

2017-10-01

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). The approach was developed and tested using fourteen years (2000-2014) of MODIS images, which showed significant spatial and temporal variability of the PC:Chla ratio, an indicator of cyanobacterial dominance. The results had unbiased RMS uncertainties of MODIS Chla and PC products were then used for cyanobacterial risk mapping with a decision tree classification model. The resulting Water Quality Decision Matrix (WQDM) was designed to assist authorities in the identification of possible intake areas, as well as specific months when higher frequency monitoring and more intense water treatment would be required if the location of the present intake area remained the same. Remote sensing cyanobacterial risk mapping provides a new tool for reservoir and lake management programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cyanobacterial defense mechanisms against foreign DNA transfer and their impact on genetic engineering

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Karina Stucken

2013-01-01

Full Text Available Cyanobacteria display a large diversity of cellular forms ranging from unicellular to complex multicellular filaments or aggregates. Species in the group present a wide range of metabolic characteristics including the fixation of atmospheric nitrogen, resistance to extreme environments, production of hydrogen, secondary metabolites and exopolysaccharides. These characteristics led to the growing interest in cyanobacteria across the fields of ecology, evolution, cell biology and biotechnology. The number of available cyanobacterial genome sequences has increased considerably in recent years, with more than 140 fully sequenced genomes to date. Genetic engineering of cyanobacteria is widely applied to the model unicellular strains Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. However the establishment of transformation protocols in many other cyanobacterial strains is challenging. One obstacle to the development of these novel model organisms is that many species have doubling times of 48 h or more, much longer than the bacterial models E. coli or B. subtilis. Furthermore, cyanobacterial defense mechanisms against foreign DNA pose a physical and biochemical barrier to DNA insertion in most strains. Here we review the various barriers to DNA uptake in the context of lateral gene transfer among microbes and the various mechanisms for DNA acquisition within the prokaryotic domain. Understanding the cyanobacterial defense mechanisms is expected to assist in the development and establishment of novel transformation protocols that are specifically suitable for this group.

Rapid reactivation of cyanobacterial photosynthesis and migration upon rehydration of desiccated marine microbial mats

NARCIS (Netherlands)

Chennu, Arjun; Grinham, Alistair; Polerecky, Lubos; de Beer, Dirk; Al-Najjar, Mohammad A.A.

2015-01-01

Desiccated cyanobacterial mats are the dominant biological feature in the Earth's arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution

Aerosolization of cyanobacterial cells across ecosystem boundaries in the McMurdo Dry Valleys, Antarctica

Science.gov (United States)

Trout-Haney, J.; Heindel, R. C.; Virginia, R. A.

2017-12-01

Cyanobacteria play a major ecological role in polar freshwaters, occurring predominately as small single cells in the water column, i.e., picocyanobacteria, or large multicellular colonies and mats that reside on the lake bottom. Cyanobacteria are also present in terrestrial polar habitats, including within soils, soil crusts, rocks, and glacial ice. Despite their predominance in polar ecosystems, the extent to which cyanobacteria move between terrestrial and aquatic landscape units remains poorly understood. In polar deserts such as the McMurdo Dry Valleys, aeolian processes influence terrestrial landscape morphology and drive the transport of sediments and other particles. Water surfaces can also act as a source of aerosolized particles, such as the production of sea spray aerosols through wave breaking in marine environments. However, aerosolization from freshwater bodies has been far less studied, especially in polar regions. We conducted a field-study to examine the transport of aerosolized cyanobacterial cells from ponds and soils in the McMurdo Dry Valleys. We used highly portable aerosol collection devices fitted with GF/F filters combusted at 500°C (0.3 µm) to collect small particles, such as picocyanobacteria (0.2 - 2 µm), from near-shore water and adjacent soil. We used epifluorescence microscopy to quantify aerosolized cells, with excitation filters for chlorophyll a (435 nm) and phycobilin pigments (572 nm), to distinguish cyanobacterial cells. We detected aerosolized picocyanobacterial cells from all ponds and soils sampled, indicating that these cells may be quite mobile and transported across ecosystem boundaries. We observed cyanobacterial cells individually, clustered, and associated with other organic material, suggesting multiple modes of cell transport. Further, we investigated the potential for aerosolization of toxin-producing cyanobacterial taxa (or unbound cyanotoxins), and the ecological and ecosystem-scale implications of

Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland

Energy Technology Data Exchange (ETDEWEB)

Touzet, N., E-mail: touzet.nicolas@itsligo.ie [Centre for Environmental Research, Innovation and Sustainability, School of Science, Department of Environmental Science, Institute of Technology Sligo, Sligo (Ireland); McCarthy, D.; Gill, A.; Fleming, G.T.A. [Microbiology, School of Natural Sciences, National University of Ireland, Galway, Galway (Ireland)

2016-05-15

The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies. - Highlights: • DGGE highlighted

Comparative summer dynamics of surface cyanobacterial communities in two connected lakes from the west of Ireland

International Nuclear Information System (INIS)

Touzet, N.; McCarthy, D.; Gill, A.; Fleming, G.T.A.

2016-01-01

The eutrophication of lakes is typically associated with high biomass proliferations of potentially toxic cyanobacteria. At a regional level, the sustainable management of water resources necessitates an approach that recognises the interconnectivity of multiple water systems within river catchments. This study examined the dynamics in summer diversity of planktonic cyanobacterial communities and microcystin toxin concentrations in two inter-connected lakes from the west of Ireland prone to nutrient enrichment. DGGE analysis of 16S rRNA gene amplicons of genotype-I cyanobacteria (typically spherical) showed changes in the communities of both Lough Corrib and Ballyquirke Lough throughout the summer, and identified cyanobacterial genotypes both unique and shared to both lakes. Microcystin concentrations, estimated via the protein phosphatase 2A inhibition assay, were greater in August than in July and June in both lakes. This was concomitant to the increased occurrence of Microcystis as evidenced by DGGE band excision and subsequent sequencing and BLAST analysis. RFLP analysis of PCR amplified mcy-A/E genes clustered together the August samples of both lakes, highlighting a potential change in microcystin producers across the two lakes. Finally, the multiple factor analysis of the combined environmental data set for the two lakes highlighted the expected pattern opposing greater water temperature and chlorophyll concentration against macronutrient concentrations, but also indicated a negative relationship between microcystin concentration and cyanobacterial diversity, possibly underlining allelopathic interactions. Despite some element of connectivity, the dissimilarity in the composition of the cyanobacterial assemblages and the timing of community change in the two lakes likely were a reflexion of niche differences determined by meteorologically-forced variation in physico-chemical parameters in the two water bodies. - Highlights: • DGGE highlighted

Cyanobacterial Diversity in Biological Soil Crusts along a Precipitation Gradient, Northwest Negev Desert, Israel.

Science.gov (United States)

Hagemann, Martin; Henneberg, Manja; Felde, Vincent J M N L; Drahorad, Sylvie L; Berkowicz, Simon M; Felix-Henningsen, Peter; Kaplan, Aaron

2015-07-01

Cyanobacteria occur worldwide but play an important role in the formation and primary activity of biological soil crusts (BSCs) in arid and semi-arid ecosystems. The cyanobacterial diversity in BSCs of the northwest Negev desert of Israel was surveyed at three fixed sampling stations situated along a precipitation gradient in the years 2010 to 2012. The three stations also are characterized by marked differences in soil features such as soil carbon, nitrogen, or electrical conductivity. The cyanobacterial biodiversity was analyzed by sequencing inserts of clone libraries harboring partial 16S rRNA gene sequences obtained with cyanobacteria-specific primers. Filamentous, non-diazotrophic strains (subsection III), particularly Microcoleus-like, dominated the cyanobacterial community (30% proportion) in all years. Specific cyanobacterial groups showed increased (e.g., Chroococcidiopsis, Leptolyngbya, and Nostoc strains) or decreased (e.g., unicellular strains belonging to the subsection I and Scytonema strains) abundances with declining water availability at the most arid, southern station, whereas many cyanobacterial strains were frequently found in the soils of all three stations. The cyanobacterial diversity at the three sampling stations appears dependent on the available precipitation, whereas the differences in soil chemistry were of lower importance.

Catchment-fed cyanobacterial blooms in brownified temperate lakes

Science.gov (United States)

Senar, O.; Creed, I. F.

2017-12-01

One of the most significant impacts of global atmospheric change is the alteration of hydrological regimes and the associated disruption of hydrological connectivity within watersheds. We show how changes in the frequency, magnitude, and duration of hydrological connectivity and disconnectivity is compromising the capacity of forest soils to store organic carbon, and increasing its export to both aquatic and atmospheric systems. Increases in dissolved organic matter (DOM) loads from forested landscapes to aquatic systems and the shift of the DOM pool to a more refractory mixture of organic compounds, a process known as brownification, alters the physical and chemical characteristics of lake environments. Furthermore, by characterizing the stages of brownification (from low to high concentrations of refractory DOM), we show a shift in the limiting factors for phytoplankton growth from macronutrients (nitrogen -N- and phosphorus -P) to micronutrients (iron -Fe) and light availability. This shift is driven by the low concentrations of DOM supplying N and P in early stages of brownification, to the strong Fe-binding capacity of refractory DOM in brownified lakes. As lakes undergo brownification, cyanobacteria adapted to scavenge Fe from DOM-Fe complexes have a competitive advantage leading to the formation of cyanobacterial blooms. Our findings provide evidence that brownification is a driving force leading to cyanobacterial blooms in lakes on forested landscapes, with expected cascading consequences to lake food webs.

Rapid development of cyanobacterial crust in the field for combating desertification.

Science.gov (United States)

Park, Chan-Ho; Li, Xin Rong; Zhao, Yang; Jia, Rong Liang; Hur, Jae-Seoun

2017-01-01

Desertification is currently a major concern, and vast regions have already been devastated in the arid zones of many countries. Combined application of cyanobacteria with soil fixing chemicals is a novel method of restoring desertified areas. Three cyanobacteria, Nostoc sp. Vaucher ex Bornet & Flahault, Phormidium sp. Kützing ex Gomont and Scytonema arcangeli Bornet ex Flahault were isolated and tested in this study. Tacki-SprayTM (TKS7), which consists of bio-polysaccharides and tackifiers, was used as a soil fixing agent. In addition, superabsorbent polymer (SAP) was applied to the soil as a water-holding material and nutrient supplement. Application of cyanobacteria with superabsorbent polymer and TKS7 (CST) remarkably improved macro-aggregate stability against water and erodibility against wind after 12 months of inoculation when compared to the control soil. The mean weight diameter and threshold friction velocity of the CST treated soil were found to be 75% and 88% of those of the approximately 20-year-old natural cyanobacterial crust (N-BSC), respectively, while these values were 68% and 73% of those of the N-BSC soil after a single treatment of cyanobacteria alone (CY). Interestingly, biological activities of CST were similar to those of CY. Total carbohydrate contents, cyanobacterial biomass, microbial biomass, soil respiration, carbon fixation and effective quantum yield of CST treated soil were enhanced by 50-100% of the N-BSC, while those of control soil were negligible. Our results suggest that combined application of cyanobacteria with soil fixing chemicals can rapidly develop cyanobacterial crust formation in the field within 12 months. The physical properties and biological activities of the inoculated cyanobacterial crust were stable during the study period. The novel method presented herein serves as another approach for combating desertification in arid regions.

Rapid development of cyanobacterial crust in the field for combating desertification.

Directory of Open Access Journals (Sweden)

Chan-Ho Park

Full Text Available Desertification is currently a major concern, and vast regions have already been devastated in the arid zones of many countries. Combined application of cyanobacteria with soil fixing chemicals is a novel method of restoring desertified areas. Three cyanobacteria, Nostoc sp. Vaucher ex Bornet & Flahault, Phormidium sp. Kützing ex Gomont and Scytonema arcangeli Bornet ex Flahault were isolated and tested in this study. Tacki-SprayTM (TKS7, which consists of bio-polysaccharides and tackifiers, was used as a soil fixing agent. In addition, superabsorbent polymer (SAP was applied to the soil as a water-holding material and nutrient supplement. Application of cyanobacteria with superabsorbent polymer and TKS7 (CST remarkably improved macro-aggregate stability against water and erodibility against wind after 12 months of inoculation when compared to the control soil. The mean weight diameter and threshold friction velocity of the CST treated soil were found to be 75% and 88% of those of the approximately 20-year-old natural cyanobacterial crust (N-BSC, respectively, while these values were 68% and 73% of those of the N-BSC soil after a single treatment of cyanobacteria alone (CY. Interestingly, biological activities of CST were similar to those of CY. Total carbohydrate contents, cyanobacterial biomass, microbial biomass, soil respiration, carbon fixation and effective quantum yield of CST treated soil were enhanced by 50-100% of the N-BSC, while those of control soil were negligible. Our results suggest that combined application of cyanobacteria with soil fixing chemicals can rapidly develop cyanobacterial crust formation in the field within 12 months. The physical properties and biological activities of the inoculated cyanobacterial crust were stable during the study period. The novel method presented herein serves as another approach for combating desertification in arid regions.

Analysis of Microcystins in Cyanobacterial Blooms from Freshwater Bodies in England

Directory of Open Access Journals (Sweden)

Andrew D. Turner

2018-01-01

Full Text Available Cyanobacterial blooms in freshwater bodies in England are currently monitored reactively, with samples containing more than 20,000 cells/mL of potentially toxin-producing species by light microscopy resulting in action by the water body owner. Whilst significantly reducing the risk of microcystin exposure, there is little data describing the levels of these toxins present in cyanobacterial blooms. This study focused on the quantitative LC-MS/MS analysis of microcystins in freshwater samples, collected across England during 2016 and found to contain potentially toxin-producing cyanobacteria. More than 50% of samples contained quantifiable concentrations of microcystins, with approximately 13% exceeding the WHO medium health threshold of 20 μg/L. Toxic samples were confirmed over a nine-month period, with a clear increase in toxins during late summer, but with no apparent geographical patterns. No statistical relationships were found between total toxin concentrations and environmental parameters. Complex toxin profiles were determined and profile clusters were unrelated to cyanobacterial species, although a dominance of MC-RR was determined in water samples from sites associated with lower rainfall. 100% of samples with toxins above the 20 μg/L limit contained cell densities above 20,000 cells/mL or cyanobacterial scum, showing the current regime is suitable for public health. Conversely, with only 18% of cell density threshold samples having total microcystins above 20 μg/L, there is the potential for reactive water closures to unnecessarily impact upon the socio-economics of the local population. In the future, routine analysis of bloom samples by LC-MS/MS would provide a beneficial confirmatory approach to the current microscopic assessment, aiding both public health and the needs of water users and industry.

Drivers of cyanobacterial diversity and community composition in mangrove soils in south-east Brazil.

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Rigonato, Janaina; Kent, Angela D; Alvarenga, Danillo O; Andreote, Fernando D; Beirigo, Raphael M; Vidal-Torrado, Pablo; Fiore, Marli F

2013-04-01

Cyanobacteria act as primary producers of carbon and nitrogen in nutrient-poor ecosystems such as mangroves. This important group of microorganisms plays a critical role in sustaining the productivity of mangrove ecosystems, but the structure and function of cyanobacteria assemblages can be perturbed by anthropogenic influences. The aim of this work was to assess the community structure and ecological drivers that influence the cyanobacterial community harboured in two Brazilian mangrove soils, and examine the long-term effects of oil contamination on these keystone species. Community fingerprinting results showed that, although cyanobacterial communities are distinct between the two mangroves, the structure and diversity of the assemblages exhibit similar responses to environmental gradients. In each ecosystem, cyanobacteria occupying near-shore areas were similar in composition, indicating importance of marine influences for structuring the community. Analysis of 16S rRNA sequences revealed the presence of diverse cyanobacterial communities in mangrove sediments, with clear differences among mangrove habitats along a transect from shore to forest. While near-shore sites in both mangroves were mainly occupied by Prochlorococcus and Synechococcus genera, sequences retrieved from other mangrove niches were mainly affiliated with uncultured cyanobacterial 16S rRNA. The most intriguing finding was the large number of potentially novel cyanobacteria 16S rRNA sequences obtained from a previously oil-contaminated site. The abundance of cyanobacterial 16S rRNA sequences observed in sites with a history of oil contamination was significantly lower than in the unimpacted areas. This study emphasized the role of environmental drivers in determining the structure of cyanobacterial communities in mangrove soils, and suggests that anthropogenic impacts may also act as ecological filters that select cyanobacterial taxa. These results are an important contribution to our

Cyanobacterial evolution during the Precambrian

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Schirrmeister, Bettina E.; Sanchez-Baracaldo, Patricia; Wacey, David

2016-07-01

Life on Earth has existed for at least 3.5 billion years. Yet, relatively little is known of its evolution during the first two billion years, due to the scarceness and generally poor preservation of fossilized biological material. Cyanobacteria, formerly known as blue green algae were among the first crown Eubacteria to evolve and for more than 2.5 billion years they have strongly influenced Earth's biosphere. Being the only organism where oxygenic photosynthesis has originated, they have oxygenated Earth's atmosphere and hydrosphere, triggered the evolution of plants -being ancestral to chloroplasts- and enabled the evolution of complex life based on aerobic respiration. Having such a strong impact on early life, one might expect that the evolutionary success of this group may also have triggered further biosphere changes during early Earth history. However, very little is known about the early evolution of this phylum and ongoing debates about cyanobacterial fossils, biomarkers and molecular clock analyses highlight the difficulties in this field of research. Although phylogenomic analyses have provided promising glimpses into the early evolution of cyanobacteria, estimated divergence ages are often very uncertain, because of vague and insufficient tree-calibrations. Results of molecular clock analyses are intrinsically tied to these prior calibration points, hence improving calibrations will enable more precise divergence time estimations. Here we provide a review of previously described Precambrian microfossils, biomarkers and geochemical markers that inform upon the early evolution of cyanobacteria. Future research in micropalaeontology will require novel analyses and imaging techniques to improve taxonomic affiliation of many Precambrian microfossils. Consequently, a better understanding of early cyanobacterial evolution will not only allow for a more specific calibration of cyanobacterial and eubacterial phylogenies, but also provide new dates for the tree

Cyanobacterial-algal cenoses in ordinary chernozems under the impact of different phytoameliorants

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Dubovik, I. E.; Suyundukov, Ya. T.; Khasanova, R. F.; Shalygina, R. R.

2016-04-01

General ecological and taxonomic characteristics of cyanobacterial-algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial-algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial-algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

Genome-wide comparative analysis of codon usage bias and codon context patterns among cyanobacterial genomes.

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Prabha, Ratna; Singh, Dhananjaya P; Sinha, Swati; Ahmad, Khurshid; Rai, Anil

2017-04-01

With the increasing accumulation of genomic sequence information of prokaryotes, the study of codon usage bias has gained renewed attention. The purpose of this study was to examine codon selection pattern within and across cyanobacterial species belonging to diverse taxonomic orders and habitats. We performed detailed comparative analysis of cyanobacterial genomes with respect to codon bias. Our analysis reflects that in cyanobacterial genomes, A- and/or T-ending codons were used predominantly in the genes whereas G- and/or C-ending codons were largely avoided. Variation in the codon context usage of cyanobacterial genes corresponded to the clustering of cyanobacteria as per their GC content. Analysis of codon adaptation index (CAI) and synonymous codon usage order (SCUO) revealed that majority of genes are associated with low codon bias. Codon selection pattern in cyanobacterial genomes reflected compositional constraints as major influencing factor. It is also identified that although, mutational constraint may play some role in affecting codon usage bias in cyanobacteria, compositional constraint in terms of genomic GC composition coupled with environmental factors affected codon selection pattern in cyanobacterial genomes. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of phosphatase activity in aquatic and terrestrial cyanobacterial strains

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Babić Olivera B.

2013-01-01

Full Text Available Cyanobacteria, as highly adaptable microorganisms, are characterized by an ability to survive in different environmental conditions, in which a significant role belongs to their enzymes. Phosphatases are enzymes produced by algae in relatively large quantities in response to a low orthophosphate concentration and their activity is significantly correlated with their primary production. The activity of these enzymes was investigated in 11 cyanobacterial strains in order to determine enzyme synthesis depending on taxonomic and ecological group of cyanobacteria. The study was conducted with 4 terrestrial cyanobacterial strains, which belong to Nostoc and Anabaena genera, and 7 filamentous water cyanobacteria of Nostoc, Oscillatoria, Phormidium and Microcystis genera. The obtained results showed that the activity of acid and alkaline phosphatases strongly depended on cyanobacterial strain and the environment from which the strain originated. Higher activity of alkaline phosphatases, ranging from 3.64 to 85.14 μmolpNP/s/dm3, was recorded in terrestrial strains compared to the studied water strains (1.11-5.96 μmolpNP/s/dm3. The activity of acid phosphatases was higher in most tested water strains (1.67-6.28 μmolpNP/s/dm3 compared to the activity of alkaline phosphatases (1.11-5.96 μmolpNP/s/dm3. Comparing enzyme activity of nitrogen fixing and non-nitrogen fixing cyanobacteria, it was found that most nitrogen fixing strains had a higher activity of alkaline phosphatases. The data obtained in this work indicate that activity of phosphatases is a strain specific property. The results further suggest that synthesis and activity of phosphatases depended on eco-physiological characteristics of the examined cyanobacterial strains. This can be of great importance for the further study of enzymes and mechanisms of their activity as a part of cyanobacterial survival strategy in environments with extreme conditions. [Projekat Ministarstva nauke Republike

Proteomic Analysis of Hepatic Tissue of Cyprinus carpio L. Exposed to Cyanobacterial Blooms in Lake Taihu, China

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Jiang, Jinlin; Wang, Xiaorong; Shan, Zhengjun; Yang, Liuyan; Zhou, Junying; Bu, Yuanqin

2014-01-01

With the rapid development of industry and agriculture and associated pollution, the cyanobacterial blooms in Lake Taihu have become a major threat to aquatic wildlife and human health. In this study, the ecotoxicological effects of cyanobacterial blooms on cage-cultured carp (Cyprinus carpio L.) in Meiliang Bay of Lake Taihu were investigated. Microcystins (MCs), major cyanobacterial toxins, have been detected in carp cultured at different experimental sites of Meiliang Bay. We observed that the accumulation of MCs in carp was closely associated with several environmental factors, including temperature, pH value, and density of cyanobacterial blooms. The proteomic profile of carp liver exposed to cyanobacterial blooms was analyzed using two-dimensional difference in-gel electrophoresis (2D-DIGE) and mass spectrometry. The toxic effects of cyanobacterial blooms on carp liver were similar to changes caused by MCs. MCs were transported into liver cells and induced the excessive production of reactive oxygen species (ROS). MCs and ROS inhibited protein phosphatase and aldehyde dehydrogenase (ALDH), directly or indirectly resulting in oxidative stress and disruption of the cytoskeleton. These effects further interfered with metabolic pathways in the liver through the regulation of series of related proteins. The results of this study indicated that cyanobacterial blooms pose a major threat to aquatic wildlife in Meiliang Bay in Lake Taihu. These results provided evidence of the molecular mechanisms underlying liver damage in carp exposed to cyanobacterial blooms. PMID:24558380

Artificially accelerating the reversal of desertification: cyanobacterial inoculation facilitates the succession of vegetation communities.

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Lan, Shubin; Zhang, Qingyi; Wu, Li; Liu, Yongding; Zhang, Delu; Hu, Chunxiang

2014-01-01

Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.

The current status of cyanobacterial nomenclature under the "prokaryotic" and the "botanical" code.

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Oren, Aharon; Ventura, Stefano

2017-10-01

Cyanobacterial taxonomy developed in the botanical world because Cyanobacteria/Cyanophyta have traditionally been identified as algae. However, they possess a prokaryotic cell structure, and phylogenetically they belong to the Bacteria. This caused nomenclature problems as the provisions of the International Code of Nomenclature for algae, fungi, and plants (ICN; the "Botanical Code") differ from those of the International Code of Nomenclature of Prokaryotes (ICNP; the "Prokaryotic Code"). While the ICN recognises names validly published under the ICNP, Article 45(1) of the ICN has not yet been reciprocated in the ICNP. Different solutions have been proposed to solve the current problems. In 2012 a Special Committee on the harmonisation of the nomenclature of Cyanobacteria was appointed, but its activity has been minimal. Two opposing proposals to regulate cyanobacterial nomenclature were recently submitted, one calling for deletion of the cyanobacteria from the groups of organisms whose nomenclature is regulated by the ICNP, the second to consistently apply the rules of the ICNP to all cyanobacteria. Following a general overview of the current status of cyanobacterial nomenclature under the two codes we present five case studies of genera for which nomenclatural aspects have been discussed in recent years: Microcystis, Planktothrix, Halothece, Gloeobacter and Nostoc.

Potential use of cyanobacterial species in bioremediation of ...

African Journals Online (AJOL)

Potential use of cyanobacterial species in bioremediation of industrial effluents. ... African Journal of Biotechnology ... Abstract. This study investigated the potential degradation of industrial effluents by environmental species of cyanobacteria.

Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

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Alchin, Bruce; Williams, Wendy

2015-04-01

In arid and semi-arid Australia, the central role of healthy soil ecosystems in broad-acre grazing lands may be attributed to the widespread presence of cyanobacterial crusts. In terms of soil nutrient cycling and stability their role is particularly crucial in a climate dominated by annual dry seasons and variable wet seasons. In this study, we aimed to measure the contribution of cyanobacteria to soil nutrient cycling under contrasting levels of disturbance associated with grazing management. Field sampling was carried out on six paired sites (twelve properties) located across an east-west 3,000 km transect that covered different rangeland types on grazing properties in northern Australia (Queensland, Northern Territory and Western Australia). At each location paired sites were established and two different management systems were assessed, cell-paddock rotations (25-400 ha) and continuous grazing (200-2,000 ha). Cyanobacterial soil crusts were recorded from all of the twelve sites and cyanobacteria with the capacity to fix nitrogen were found at ten of the twelve sites. The overall diversity of cyanobacteria varied from three to ten species under any type of grazing system. As field work was conducted in the dry season, it is likely that the diversity may be greater in the wet season than the initial data may indicate. The average cyanobacterial soil crust cover across soil surfaces, between grass tussocks, during the dry season was estimated to be 50.9% and, 42.6% in the early wet season. This reflected longer established crust cover (dry season) versus newly established crusts. There was a high level of variability in the biomass of cyanobacteria however; the grazing system did not have any marked effect on the biomass for any one rangeland type. The grazing system differences did not appear to significantly influence the diversity at any location except on a floodplain in the Pilbara (WA). Biological nitrogen fixation by cyanobacteria was recorded at all

Genotoxicity and potential carcinogenicity of cyanobacterial toxins - a review.

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Zegura, Bojana; Straser, Alja; Filipič, Metka

2011-01-01

The occurrence of cyanobacterial blooms has increased significantly in many regions of the world in the last century due to water eutrophication. These blooms are hazardous to humans, animals, and plants due to the production of cyanotoxins, which can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). There is evidence that certain cyanobacterial toxins are genotoxic and carcinogenic; however, the mechanisms of their potential carcinogenicity are not well understood. The most frequently occurring and widespread cyanotoxins in brackish and freshwater blooms are the cyclic heptapeptides, i.e., microcystins (MCs), and the pentapeptides, i.e., nodularins (NODs). The main mechanism associated with potential carcinogenic activity of MCs and NOD is the inhibition of protein phosphatases, which leads to the hyperphosphorylation of cellular proteins, which is considered to be associated with their tumor-promoting activity. Apart from this, MCs and NOD induce increased formation of reactive oxygen species and, consequently, oxidative DNA damage. There is also evidence that MCs and NOD induce micronuclei, and NOD was shown to have aneugenic activity. Both cyanotoxins interfere with DNA damage repair pathways, which, along with DNA damage, is an important factor involved in the carcinogenicity of these agents. Furthermore, these toxins increase the expression of TNF-α and early-response genes, including proto-oncogenes, genes involved in the response to DNA damage, cell cycle arrest, and apoptosis. Rodent studies indicate that MCs and NOD are tumor promotors, whereas NOD is thought to have also tumor-initiating activity. Another cyanobacterial toxin, cylindrospermopsin (CYN), which has been neglected for a long time, is lately being increasingly found in the freshwater environment. The principal mechanism of its toxicity is the irreversible inhibition of protein synthesis. It is pro

Cyanobacterial diversity in extreme environments in Baja California, Mexico: a polyphasic study.

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López-Cortés, A; García-Pichel, F; Nübel, U; Vázquez-Juárez, R

2001-12-01

Cyanobacterial diversity from two geographical areas of Baja California Sur, Mexico, were studied: Bahia Concepcion, and Ensenada de Aripez. The sites included hypersaline ecosystems, sea bottom, hydrothermal springs, and a shrimp farm. In this report we describe four new morphotypes, two are marine epilithic from Bahia Concepcion, Dermocarpa sp. and Hyella sp. The third, Geitlerinema sp., occurs in thermal springs and in shrimp ponds, and the fourth, Tychonema sp., is from a shrimp pond. The partial sequences of the 16S rRNA genes and the phylogenetic relationship of four cyanobacterial strains (Synechococcus cf. elongatus, Leptolyngbya cf. thermalis, Leptolyngbya sp., and Geitlerinema sp.) are also presented. Polyphasic studies that include the combination of light microscopy, cultures and the comparative analysis of 16S rRNA gene sequences provide the most powerful approach currently available to establish the diversity of these oxygenic photosynthetic microorganisms in culture and in nature.

Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors

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Maxine A.D. Mowe

2014-12-01

Full Text Available Toxic cyanobacterial blooms are a major issue in freshwater systems in many countries. The potentially toxic species and their ecological causes are likely to be different in tropical zones from those in temperate water bodies; however, studies on tropical toxic cyanobacterial blooms are sporadic and currently there is no global synthesis. In this review, we examined published information on tropical cyanobacterial bloom occurrence and toxin production to investigate patterns in their growth and distribution. Microcystis was the most frequently occurring bloom genus throughout tropical Asia, Africa and Central America, while Cylindrospermopsis and Anabaena blooms occurred in various locations in tropical Australia, America and Africa. Microcystis blooms were more prevalent during the wet season while Cylindrospermopsis blooms were more prevalent during the dry period. Microcystin was the most encountered toxin throughout the tropics. A meta-analysis of tropical cyanobacterial blooms showed that Microcystis blooms were more associated with higher total nitrogen concentrations, while Cylindrospermopsis blooms were more associated with higher maximum temperatures. Meta-analysis also showed a positive linear relationship between levels of microcystin and N:P (nitrate:phosphate ratio. Tropical African Microcystis blooms were found to have the lowest microcystin levels in relation to biomass and N:P (nitrate:phosphate compared to tropical Asian, Australian and American blooms. There was also no significant correlation between microcystin concentration and cell concentration for tropical African blooms as opposed to tropical Asian and American blooms. Our review illustrates that some cyanobacteria and toxins are more prevalent in tropical areas. While some tropical countries have considerable information regarding toxic blooms, others have few or no reported studies. 

Computational prediction of cAMP receptor protein (CRP binding sites in cyanobacterial genomes

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Su Zhengchang

2009-01-01

Full Text Available Abstract Background Cyclic AMP receptor protein (CRP, also known as catabolite gene activator protein (CAP, is an important transcriptional regulator widely distributed in many bacteria. The biological processes under the regulation of CRP are highly diverse among different groups of bacterial species. Elucidation of CRP regulons in cyanobacteria will further our understanding of the physiology and ecology of this important group of microorganisms. Previously, CRP has been experimentally studied in only two cyanobacterial strains: Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120; therefore, a systematic genome-scale study of the potential CRP target genes and binding sites in cyanobacterial genomes is urgently needed. Results We have predicted and analyzed the CRP binding sites and regulons in 12 sequenced cyanobacterial genomes using a highly effective cis-regulatory binding site scanning algorithm. Our results show that cyanobacterial CRP binding sites are very similar to those in E. coli; however, the regulons are very different from that of E. coli. Furthermore, CRP regulons in different cyanobacterial species/ecotypes are also highly diversified, ranging from photosynthesis, carbon fixation and nitrogen assimilation, to chemotaxis and signal transduction. In addition, our prediction indicates that crp genes in modern cyanobacteria are likely inherited from a common ancestral gene in their last common ancestor, and have adapted various cellular functions in different environments, while some cyanobacteria lost their crp genes as well as CRP binding sites during the course of evolution. Conclusion The CRP regulons in cyanobacteria are highly diversified, probably as a result of divergent evolution to adapt to various ecological niches. Cyanobacterial CRPs may function as lineage-specific regulators participating in various cellular processes, and are important in some lineages. However, they are dispensable in some other lineages. The

The antibiotic resistome of free-living and particle-attached bacteria under a reservoir cyanobacterial bloom.

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Guo, Yunyan; Liu, Min; Liu, Lemian; Liu, Xuan; Chen, Huihuang; Yang, Jun

2018-05-04

In freshwater systems, both antibiotic resistance genes (ARGs) and cyanobacterial blooms attract global public health concern. Cyanobacterial blooms can greatly impact bacterial taxonomic communities, but very little is known about the influence of the blooms on antibiotic resistance functional community. In this study, the ARGs in both free-living (FL) and particle-attached (PA) bacteria under bloom and non-bloom conditions were simultaneously investigated in a subtropical reservoir using high-throughput approaches. In total, 145 ARGs and 9 mobile genetic elements (MGEs) were detected. The most diverse and dominant of which (68.93%) were multidrug resistance genes and efflux pump mechanism. The richness of ARGs in both FL and PA bacteria was significantly lower during the bloom period compared with non-bloom period. The abundance of ARGs in FL bacteria was significantly lower under bloom condition than in the non-bloom period, but the abundance of ARGs in PA bacteria stayed constant. More importantly, the resistant functional community in PA bacteria was more strongly influenced by the cyanobacterial bloom than in the FL bacteria, although >96% ARGs were shared in both FL and PA bacteria or both bloom and non-bloom periods. We also compared the community compositions between taxonomy and function, and found antibiotic resistant communities were highly variable and exhibited lower similarity between bloom and non-bloom periods than seen in the taxonomic composition, with an exception of FL bacteria. Altogether, cyanobacterial blooms appear to have stronger inhibitory effect on ARG abundance in FL bacteria, and stronger influence on antibiotic resistant community composition in PA bacteria. Our results further suggested that both neutral and selective processes interactively affected the ARG composition dynamics of the FL and PA bacteria. However, the antibiotic resistant community of FL bacteria exhibited a higher level of temporal stochasticity following the bloom

Occurrence and elimination of cyanobacterial toxins in drinking water treatment plants

International Nuclear Information System (INIS)

Hoeger, Stefan J.; Hitzfeld, Bettina C.; Dietrich, Daniel R.

2005-01-01

Toxin-producing cyanobacteria (blue-green algae) are abundant in surface waters used as drinking water resources. The toxicity of one group of these toxins, the microcystins, and their presence in surface waters used for drinking water production has prompted the World Health Organization (WHO) to publish a provisional guideline value of 1.0 μg microcystin (MC)-LR/l drinking water. To verify the efficiency of two different water treatment systems with respect to reduction of cyanobacterial toxins, the concentrations of MC in water samples from surface waters and their associated water treatment plants in Switzerland and Germany were investigated. Toxin concentrations in samples from drinking water treatment plants ranged from below 1.0 μg MC-LR equiv./l to more than 8.0 μg/l in raw water and were distinctly below 1.0 μg/l after treatment. In addition, data to the worldwide occurrence of cyanobacteria in raw and final water of water works and the corresponding guidelines for cyanobacterial toxins in drinking water worldwide are summarized

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins.

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Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma; Cillero-Castro, Carmen; Budzyńska, Agnieszka; Goldyn, Ryszard; Kozak, Anna; Rosińska, Joanna; Szeląg-Wasielewska, Elżbieta; Domek, Piotr; Jakubowska-Krepska, Natalia; Kwasizur, Kinga; Messyasz, Beata; Pełechaty, Aleksandra; Pełechaty, Mariusz; Kokocinski, Mikolaj; García-Murcia, Ana; Real, Monserrat; Romans, Elvira; Noguero-Ribes, Jordi; Duque, David Parreño; Fernández-Morán, Elísabeth; Karakaya, Nusret; Häggqvist, Kerstin; Demir, Nilsun; Beklioğlu, Meryem; Filiz, Nur; Levi, Eti E.; Iskin, Uğur; Bezirci, Gizem; Tavşanoğlu, Ülkü Nihan; Özhan, Koray; Gkelis, Spyros; Panou, Manthos; Fakioglu, Özden; Avagianos, Christos; Kaloudis, Triantafyllos; Çelik, Kemal; Yilmaz, Mete; Marcé, Rafael; Catalán, Nuria; Bravo, Andrea G.; Buck, Moritz; Colom-Montero, William; Mustonen, Kristiina; Pierson, Don; Yang, Yang; Raposeiro, Pedro M.; Gonçalves, Vítor; Antoniou, Maria G.; Tsiarta, Nikoletta; McCarthy, Valerie; Perello, Victor C.; Feldmann, Tõnu; Laas, Alo; Panksep, Kristel; Tuvikene, Lea; Gagala, Ilona; Mankiewicz-Boczek, Joana; Yağcı, Meral Apaydın; Çınar, Şakir; Çapkın, Kadir; Yağcı, Abdulkadir; Cesur, Mehmet; Bilgin, Fuat; Bulut, Cafer; Uysal, Rahmi; Obertegger, Ulrike; Boscaini, Adriano; Flaim, Giovanna; Salmaso, Nico; Cerasino, Leonardo; Richardson, Jessica; Visser, Petra M.; Verspagen, Jolanda M. H.; Karan, Tünay; Soylu, Elif Neyran; Maraşlıoğlu, Faruk; Napiórkowska-Krzebietke, Agnieszka; Ochocka, Agnieszka; Pasztaleniec, Agnieszka; Antão-Geraldes, Ana M.; Vasconcelos, Vitor; Morais, João; Vale, Micaela; Köker, Latife; Akçaalan, Reyhan; Albay, Meriç; Špoljarić Maronić, Dubravka; Stević, Filip; Žuna Pfeiffer, Tanja; Fonvielle, Jeremy; Straile, Dietmar; Rothhaupt, Karl-Otto; Hansson, Lars-Anders; Urrutia-Cordero, Pablo; Bláha, Luděk; Geriš, Rodan; Fránková, Markéta; Koçer, Mehmet Ali Turan; Alp, Mehmet Tahir; Remec-Rekar, Spela; Elersek, Tina; Triantis, Theodoros; Zervou, Sevasti-Kiriaki; Hiskia, Anastasia; Haande, Sigrid; Skjelbred, Birger; Madrecka, Beata; Nemova, Hana; Drastichova, Iveta; Chomova, Lucia; Edwards, Christine; Sevindik, Tuğba Ongun; Tunca, Hatice; Önem, Burçin; Aleksovski, Boris; Krstić, Svetislav; Vucelić, Itana Bokan; Nawrocka, Lidia; Salmi, Pauliina; Machado-Vieira, Danielle; de Oliveira, Alinne Gurjão; Delgado-Martín, Jordi; García, David; Cereijo, Jose Luís; Gomà, Joan; Trapote, Mari Carmen; Vegas-Vilarrúbia, Teresa; Obrador, Biel; Grabowska, Magdalena; Karpowicz, Maciej; Chmura, Damian; Úbeda, Bárbara; Gálvez, José Ángel; Özen, Arda; Christoffersen, Kirsten Seestern; Warming, Trine Perlt; Kobos, Justyna; Mazur-Marzec, Hanna; Pérez-Martínez, Carmen; Ramos-Rodríguez, Eloísa; Arvola, Lauri; Alcaraz-Párraga, Pablo; Toporowska, Magdalena; Pawlik-Skowronska, Barbara; Niedźwiecki, Michał; Pęczuła, Wojciech; Leira, Manel; Hernández, Armand; Moreno-Ostos, Enrique; Blanco, José María; Rodríguez, Valeriano; Montes-Pérez, Jorge Juan; Palomino, Roberto L.; Rodríguez-Pérez, Estela; Carballeira, Rafael; Camacho, Antonio; Picazo, Antonio; Rochera, Carlos; Santamans, Anna C.; Ferriol, Carmen; Romo, Susana; Soria, Juan Miguel; Dunalska, Julita; Sieńska, Justyna; Szymański, Daniel; Kruk, Marek; Kostrzewska-Szlakowska, Iwona; Jasser, Iwona; Žutinić, Petar; Gligora Udovič, Marija; Plenković-Moraj, Anđelka; Frąk, Magdalena; Bańkowska-Sobczak, Agnieszka; Wasilewicz, Michał; Özkan, Korhan; Maliaka, Valentini; Kangro, Kersti; Grossart, Hans-Peter; Paerl, Hans W.; Carey, Cayelan C.; Ibelings, Bas W.

2018-04-13

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

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Evanthia Mantzouki

2018-04-01

Full Text Available Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins. Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a and cytotoxins (e.g., cylindrospermopsin due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.

Accumulation of cyanobacterial toxins in freshwater "seafood" and its consequences for public health: A review

NARCIS (Netherlands)

Ibelings, B.W.; Chorus, I.

2007-01-01

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in “seafood” collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and

The Geographic Distribution of Liver Cancer in Canada Does Not Associate with Cyanobacterial Toxin Exposure

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Meaghan A. Labine

2015-11-01

Full Text Available Background: The incidence of liver cancer has been increasing in Canada over the past decade, as has cyanobacterial contamination of Canadian freshwater lakes and drinking water sources. Cyanotoxins released by cyanobacteria have been implicated in the pathogenesis of liver cancer. Objective: To determine whether a geographic association exists between liver cancer and surrogate markers of cyanobacterial contamination of freshwater lakes in Canada. Methods: A negative binomial regression model was employed based on previously identified risk factors for liver cancer. Results: No association existed between the geographic distribution of liver cancer and surrogate markers of cyanobacterial contamination. As predicted, significant associations existed in areas with a high prevalence of hepatitis B virus infection, large immigrant populations and urban residences. Discussion and Conclusions: The results of this study suggest that cyanobacterial contamination of freshwater lakes does not play an important role in the increasing incidence of liver cancer in Canada.

Contrasting the Genetic Patterns of Microbial Communities in Soda Lakes with and without Cyanobacterial Bloom.

Science.gov (United States)

Andreote, Ana P D; Dini-Andreote, Francisco; Rigonato, Janaina; Machineski, Gabriela Silva; Souza, Bruno C E; Barbiero, Laurent; Rezende-Filho, Ary T; Fiore, Marli F

2018-01-01

Soda lakes have high levels of sodium carbonates and are characterized by salinity and elevated pH. These ecosystems are found across Africa, Europe, Asia, Australia, North, Central, and South America. Particularly in Brazil, the Pantanal region has a series of hundreds of shallow soda lakes (ca. 600) potentially colonized by a diverse haloalkaliphilic microbial community. Biological information of these systems is still elusive, in particular data on the description of the main taxa involved in the biogeochemical cycling of life-important elements. Here, we used metagenomic sequencing to contrast the composition and functional patterns of the microbial communities of two distinct soda lakes from the sub-region Nhecolândia, state of Mato Grosso do Sul, Brazil. These two lakes differ by permanent cyanobacterial blooms (Salina Verde, green-water lake) and by no record of cyanobacterial blooms (Salina Preta, black-water lake). The dominant bacterial species in the Salina Verde bloom was Anabaenopsis elenkinii . This cyanobacterium altered local abiotic parameters such as pH, turbidity, and dissolved oxygen and consequently the overall structure of the microbial community. In Salina Preta, the microbial community had a more structured taxonomic profile. Therefore, the distribution of metabolic functions in Salina Preta community encompassed a large number of taxa, whereas, in Salina Verde, the functional potential was restrained across a specific set of taxa. Distinct signatures in the abundance of genes associated with the cycling of carbon, nitrogen, and sulfur were found. Interestingly, genes linked to arsenic resistance metabolism were present at higher abundance in Salina Verde and they were associated with the cyanobacterial bloom. Collectively, this study advances fundamental knowledge on the composition and genetic potential of microbial communities inhabiting tropical soda lakes.

Contrasting the Genetic Patterns of Microbial Communities in Soda Lakes with and without Cyanobacterial Bloom

Science.gov (United States)

Andreote, Ana P. D.; Dini-Andreote, Francisco; Rigonato, Janaina; Machineski, Gabriela Silva; Souza, Bruno C. E.; Barbiero, Laurent; Rezende-Filho, Ary T.; Fiore, Marli F.

2018-01-01

Soda lakes have high levels of sodium carbonates and are characterized by salinity and elevated pH. These ecosystems are found across Africa, Europe, Asia, Australia, North, Central, and South America. Particularly in Brazil, the Pantanal region has a series of hundreds of shallow soda lakes (ca. 600) potentially colonized by a diverse haloalkaliphilic microbial community. Biological information of these systems is still elusive, in particular data on the description of the main taxa involved in the biogeochemical cycling of life-important elements. Here, we used metagenomic sequencing to contrast the composition and functional patterns of the microbial communities of two distinct soda lakes from the sub-region Nhecolândia, state of Mato Grosso do Sul, Brazil. These two lakes differ by permanent cyanobacterial blooms (Salina Verde, green-water lake) and by no record of cyanobacterial blooms (Salina Preta, black-water lake). The dominant bacterial species in the Salina Verde bloom was Anabaenopsis elenkinii. This cyanobacterium altered local abiotic parameters such as pH, turbidity, and dissolved oxygen and consequently the overall structure of the microbial community. In Salina Preta, the microbial community had a more structured taxonomic profile. Therefore, the distribution of metabolic functions in Salina Preta community encompassed a large number of taxa, whereas, in Salina Verde, the functional potential was restrained across a specific set of taxa. Distinct signatures in the abundance of genes associated with the cycling of carbon, nitrogen, and sulfur were found. Interestingly, genes linked to arsenic resistance metabolism were present at higher abundance in Salina Verde and they were associated with the cyanobacterial bloom. Collectively, this study advances fundamental knowledge on the composition and genetic potential of microbial communities inhabiting tropical soda lakes. PMID:29520256

Contrasting the Genetic Patterns of Microbial Communities in Soda Lakes with and without Cyanobacterial Bloom

Directory of Open Access Journals (Sweden)

Ana P. D. Andreote

2018-02-01

Full Text Available Soda lakes have high levels of sodium carbonates and are characterized by salinity and elevated pH. These ecosystems are found across Africa, Europe, Asia, Australia, North, Central, and South America. Particularly in Brazil, the Pantanal region has a series of hundreds of shallow soda lakes (ca. 600 potentially colonized by a diverse haloalkaliphilic microbial community. Biological information of these systems is still elusive, in particular data on the description of the main taxa involved in the biogeochemical cycling of life-important elements. Here, we used metagenomic sequencing to contrast the composition and functional patterns of the microbial communities of two distinct soda lakes from the sub-region Nhecolândia, state of Mato Grosso do Sul, Brazil. These two lakes differ by permanent cyanobacterial blooms (Salina Verde, green-water lake and by no record of cyanobacterial blooms (Salina Preta, black-water lake. The dominant bacterial species in the Salina Verde bloom was Anabaenopsis elenkinii. This cyanobacterium altered local abiotic parameters such as pH, turbidity, and dissolved oxygen and consequently the overall structure of the microbial community. In Salina Preta, the microbial community had a more structured taxonomic profile. Therefore, the distribution of metabolic functions in Salina Preta community encompassed a large number of taxa, whereas, in Salina Verde, the functional potential was restrained across a specific set of taxa. Distinct signatures in the abundance of genes associated with the cycling of carbon, nitrogen, and sulfur were found. Interestingly, genes linked to arsenic resistance metabolism were present at higher abundance in Salina Verde and they were associated with the cyanobacterial bloom. Collectively, this study advances fundamental knowledge on the composition and genetic potential of microbial communities inhabiting tropical soda lakes.

Observations of volatile organic compounds over the North Atlantic Ocean: relationships to dominant cyanobacterial populations.

Science.gov (United States)

Swarthout, R.; Rossell, R.; Sive, B. C.; Zhou, Y.; Reddy, C. M.; Valentine, D. L.; Cox, D.

2017-12-01

Marine cyanobacteria are abundant primary producers that can have a major influence on the oceanic biogeochemical cycles. In particular, the prominent cyanobacterial genera Prochlorococcus, Synechococcus, and Trichodesmium can impact the air-sea flux of volatile organic compounds (VOCs) including reactive compounds, such as isoprene, that control the oxidative capacity of the atmosphere and climate-relevant compounds, such as dimethyl sulfide. These groups of cyanobacteria have been estimated to increase in abundance by up to 29% by the end of the century as a result of rising sea surface temperatures and dissolved carbon dioxide concentrations. Given their current and predicted future abundance, understanding the role of different cyanobacterial populations on VOC emissions from the ocean is critical in understanding the future oxidative capacity of the remote atmosphere and climate feedback cycles. During the May 2017 Phosphorus, Hydrocarbons, and Transcriptomics cruise aboard the R/V Neil Armstrong, 160 whole air canister samples were collected along a transect through the North Atlantic from Woods Hole, MA to Bermuda and back with 24-hour stops at nine stations encompassing different nutrient regimes and cyanobacterial populations. At each station, a diurnal time series of samples was collected and higher frequency sampling was conducted during transits of the north wall. Canister samples were analyzed on a five-detector gas chromatography system for over 80 individual VOCs including biogenics, aromatics, chlorinated and brominated compounds, and sulfur containing compounds. Trends in reactive and climate-relevant VOCs will be discussed as a function of the predominant cyanobacterial populations at each sample location. These data provide increased information on the spatial and diurnal variability of trace gases associated with these globally important photosynthetic cyanobacteria.

An integrated method for removal of harmful cyanobacterial blooms in eutrophic lakes

International Nuclear Information System (INIS)

Wang Zhicong; Li Dunhai; Qin Hongjie; Li Yinxia

2012-01-01

As the eutrophication of lakes becomes an increasingly widespread phenomenon, cyanobacterial blooms are occurring in many countries. Although some research has been reported, there is currently no good method for bloom removal. We propose here a new two-step integrated approach to resolve this problem. The first step is the inactivation of the cyanobacteria via the addition of H 2 O 2 . We found 60 mg/L was the lowest effective dose for a cyanobacterial concentration corresponding to 100 μg/L chlorophyll-a. The second step is the flocculation and sedimentation of the inactivated cyanobacteria. We found the addition of lake sediment clay (2 g/L) plus polymeric ferric sulfate (20 mg/L) effectively deposited them on the lake bottom. Since algaecides and flocculants had been used separately in previous reports, we innovatively combined these two types of reagents to remove blooms from the lake surface and to improve the dissolved oxygen content of lake sediments. - Graphical abstract: The mechanism for the removal of cyanobacterial blooms by using H 2 O 2 , polymeric ferric sulfate (PFS) and lake sediment clay. Display Omitted Highlights: ► We combined algaecide and flocculants together to control cyanobacterial blooms. ► H 2 O 2 was used to irreversibly inactivate the photosynthesis of cyanobacteria. ► Lake sediment clay and polymeric ferric sulfate were used to deposit cyanobacteria. ► Removal rate was very high and re-suspension rate was very low under disturbance. ► The inactivated cyanobacteria could not serve as a seed source for the next bloom. - Inactivation by H 2 O 2 and sedimentation using polymeric ferric sulfate and sediment clay demonstrated high integrated efficiency in removal of cyanobacterial blooms.

Carotenoids assist in cyanobacterial Photosystem II assembly and function

Directory of Open Access Journals (Sweden)

Tomas eZakar

2016-03-01

Full Text Available Carotenoids (carotenes and xanthophylls are ubiquitous constituents of living organisms. They are protective agents against oxidative stresses and serve as modulators of membrane microviscosity. As antioxidants they can protect photosynthetic organisms from free radicals like reactive oxygen species that originate from water splitting, the first step of photosynthesis. We summarize the structural and functional roles of carotenoids in connection with cyanobacterial Photosystem II. Although carotenoids are hydrophobic molecules, their complexes with proteins also allow cytoplasmic localization. In cyanobacterial cells such complexes are called orange carotenoid proteins, and they protect Photosystem II and Photosystem I by preventing their overexcitation through phycobilisomes. Recently it has been observed that carotenoids are not only required for the proper functioning, but also for the structural stability of phycobilisomes.

Feasibility study on production of a matrix reference material for cyanobacterial toxins.

Science.gov (United States)

Hollingdale, Christie; Thomas, Krista; Lewis, Nancy; Békri, Khalida; McCarron, Pearse; Quilliam, Michael A

2015-07-01

The worldwide increase in cyanobacterial contamination of freshwater lakes and rivers is of great concern as many cyanobacteria produce potent hepatotoxins and neurotoxins (cyanotoxins). Such toxins pose a threat to aquatic ecosystems, livestock, and drinking water supplies. In addition, dietary supplements prepared from cyanobacteria can pose a risk to consumers if they contain toxins. Analytical monitoring for toxins in the environment and in consumer products is essential for the protection of public health. Reference materials (RMs) are an essential tool for the development and validation of analytical methods and are necessary for ongoing quality control of monitoring operations. Since the availability of appropriate RMs for cyanotoxins has been very limited, the present study was undertaken to examine the feasibility of producing a cyanobacterial matrix RM containing various cyanotoxins. The first step was large-scale culturing of various cyanobacterial cultures that produce anatoxins, microcystins, and cylindrospermopsins. After harvesting, the biomass was lyophilized, blended, homogenized, milled, and bottled. The moisture content and physical characteristics were assessed in order to evaluate the effectiveness of the production process. Toxin levels were measured by liquid chromatography with tandem mass spectrometry and ultraviolet detection. The reference material was found to be homogeneous for toxin content. Stability studies showed no significant degradation of target toxins over a period of 310 days at temperatures up to +40 °C except for the anatoxin-a, which showed some degradation at +40 °C. These results show that a fit-for-purpose matrix RM for cyanotoxins can be prepared using the processes and techniques applied in this work.

Molecular Diffusion through Cyanobacterial Septal Junctions.

Science.gov (United States)

Nieves-Morión, Mercedes; Mullineaux, Conrad W; Flores, Enrique

2017-01-03

Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N 2 -fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO 2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP) assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the "septal junctions" (formerly known as "microplasmodesmata") linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans. Although bacteria are frequently considered just as unicellular organisms, there are bacteria that behave as true multicellular organisms. The heterocyst-forming cyanobacteria grow as filaments in which cells communicate. Intercellular molecular exchange is thought to be mediated by septal junctions. Here, we show that intercellular transfer of fluorescent markers in the cyanobacterial filament has the physical properties of simple diffusion. Thus, cyanobacterial septal junctions are functionally analogous to metazoan gap junctions

Cyanobacterial composition and spatial distribution based on pyrosequencing data in the Gurbantunggut Desert, Northwestern China.

Science.gov (United States)

Zhang, Bingchang; Li, Renhui; Xiao, Peng; Su, Yangui; Zhang, Yuanming

2016-03-01

Cyanobacteria are the primary colonizers and form a dominant component of soil photosynthetic communities in biological soil crusts. They are crucial in improving soil environments, namely accumulating soil carbon and nitrogen. Many classical studies have examined cyanobacterial diversity in desert crusts, but relatively few comprehensive molecular surveys have been conducted. We used 454 pyrosequencing of 16S rRNA to investigate cyanobacterial composition and distribution on regional scales in the Gurbantunggut Desert. The relationship between cyanobacterial distribution and environmental factors was also explored. A total of 24,973 cyanobacteria partial 16S rRNA gene sequences were obtained, and 507OTUs were selected, as most OTUs had very few reads. Among these, 347 OTU sequences were of cyanobacteria origin, belonging to Oscillatoriales, Nostocales, Chroococcales, and uncultured cyanobacterium clone, respectively. Microcoleus vaginatus, Chroococcidiopsis spp. and M. steenstrupii were the dominant species in most areas of the Gurbantunggut Desert. Compared with other desert, the Gurbantunggut Desert differed in the prominence of Chroococcidiopsis spp. and lack of Pseudanabaenales. Species composition and abundance of cyanobacteria also showed distinct variations. Soil texture, precipitation, and nutrients and salt levels affected cyanobacterial distribution. Increased precipitation was helpful in improving cyanobacterial diversity. A higher content of coarse sand promoted the colonization and growth of Oscillatoriales and some phylotypes of Chroococcales. The fine-textured soil with higher nutrients and salts supported more varied populations of cyanobacteria, namely some heterocystous cyanobacteria. The results suggested that the Gurbantunggut Desert was rich in cyanobacteria and that precipitation was a primary regulating factor for cyanobacterial composition on a regional scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of Chemical and Physico-Chemical Properties of Cyanobacterial Lipids for Biodiesel Production

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Heizir F. De Castro

2013-07-01

Full Text Available Five non-toxin producing cyanobacterial isolates from the genera Synechococcus, Trichormus, Microcystis, Leptolyngbya and Chlorogloea were examined in terms of quantity and quality as lipid feedstock for biofuel production. Under the conditions used in this study, the biomass productivity ranged from 3.7 to 52.7 mg·L−1·day−1 in relation to dry biomass, while the lipid productivity varied between 0.8 and 14.2 mg·L−1·day−1. All cyanobacterial strains evaluated yielded lipids with similar fatty acid composition to those present in the seed oils successfully used for biodiesel synthesis. However, by combining biomass and lipid productivity parameters, the greatest potential was found for Synechococcus sp. PCC7942, M. aeruginosa NPCD-1 and Trichormus sp. CENA77. The chosen lipid samples were further characterized using Fourier Transform Infrared spectroscopy (FTIR, viscosity and thermogravimetry and used as lipid feedstock for biodiesel synthesis by heterogeneous catalysis.

A curated database of cyanobacterial strains relevant for modern taxonomy and phylogenetic studies

OpenAIRE

Ramos, Vitor; Morais, Jo?o; Vasconcelos, Vitor M.

2017-01-01

The dataset herein described lays the groundwork for an online database of relevant cyanobacterial strains, named CyanoType (http://lege.ciimar.up.pt/cyanotype). It is a database that includes categorized cyanobacterial strains useful for taxonomic, phylogenetic or genomic purposes, with associated information obtained by means of a literature-based curation. The dataset lists 371 strains and represents the first version of the database (CyanoType v.1). Information for each strain includes st...

Experimental additions of aluminum sulfate and ammonium nitrate to in situ mesocosms to reduce cyanobacterial biovolume and microcystin concentration

Science.gov (United States)

Harris, Ted D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

2014-01-01

Recent studies suggest that nitrogen additions to increase the total nitrogen:total phosphorus (TN:TP) ratio may reduce cyanobacterial biovolume and microcystin concentration in reservoirs. In systems where TP is >100 μg/L, however, nitrogen additions to increase the TN:TP ratio could cause ammonia, nitrate, or nitrite toxicity to terrestrial and aquatic organisms. Reducing phosphorus via aluminum sulfate (alum) may be needed prior to nitrogen additions aimed at increasing the TN:TP ratio. We experimentally tested this sequential management approach in large in situ mesocosms (70.7 m3) to examine effects on cyanobacteria and microcystin concentration. Because alum removes nutrients and most seston from the water column, alum treatment reduced both TN and TP, leaving post-treatment TN:TP ratios similar to pre-treatment ratios. Cyanobacterial biovolume was reduced after alum addition, but the percent composition (i.e., relative) cyanobacterial abundance remained unchanged. A single ammonium nitrate (nitrogen) addition increased the TN:TP ratio 7-fold. After the TN:TP ratio was >50 (by weight), cyanobacterial biovolume and abundance were reduced, and chrysophyte and cryptophyte biovolume and abundance increased compared to the alum treatment. Microcystin was not detectable until the TN:TP ratio was <50. Although both treatments reduced cyanobacteria, only the nitrogen treatment seemed to stimulate energy flow from primary producers to zooplankton, which suggests that combining alum and nitrogen treatments may be a viable in-lake management strategy to reduce cyanobacteria and possibly microcystin concentrations in high-phosphorus systems. Additional studies are needed to define best management practices before combined alum and nitrogen additions are implemented as a reservoir management strategy.

Dynamics of cyanobacterial bloom formation during short-term hydrodynamic fluctuation in a large shallow, eutrophic, and wind-exposed Lake Taihu, China.

Science.gov (United States)

Wu, Tingfeng; Qin, Boqiang; Zhu, Guangwei; Luo, Liancong; Ding, Yanqing; Bian, Geya

2013-12-01

Short-term hydrodynamic fluctuations caused by extreme weather events are expected to increase worldwide because of global climate change, and such fluctuations can strongly influence cyanobacterial blooms. In this study, the cyanobacterial bloom disappearance and reappearance in Lake Taihu, China, in response to short-term hydrodynamic fluctuations, was investigated by field sampling, long-term ecological records, high-frequency sensors and MODIS satellite images. The horizontal drift caused by the dominant easterly wind during the phytoplankton growth season was mainly responsible for cyanobacterial biomass accumulation in the western and northern regions of the lake and subsequent bloom formation over relatively long time scales. The cyanobacterial bloom changed slowly under calm or gentle wind conditions. In contrast, the short-term bloom events within a day were mainly caused by entrainment and disentrainment of cyanobacterial colonies by wind-induced hydrodynamics. Observation of a westerly event in Lake Taihu revealed that when the 30 min mean wind speed (flow speed) exceeded the threshold value of 6 m/s (5.7 cm/s), cyanobacteria in colonies were entrained by the wind-induced hydrodynamics. Subsequently, the vertical migration of cyanobacterial colonies was controlled by hydrodynamics, resulting in thorough mixing of algal biomass throughout the water depth and the eventual disappearance of surface blooms. Moreover, the intense mixing can also increase the chance for forming larger and more cyanobacterial colonies, namely, aggregation. Subsequently, when the hydrodynamics became weak, the cyanobacterial colonies continuously float upward without effective buoyancy regulation, and cause cyanobacterial bloom explosive expansion after the westerly. Furthermore, the results of this study indicate that the strong wind happening frequently during April and October can be an important cause of the formation and expansion of cyanobacterial blooms in Lake Taihu.

Fatty Acid Composition of Six Freshwater Wild Cyanobacterial Species

Czech Academy of Sciences Publication Activity Database

Řezanka, Tomáš; Dor, I.; Prell, Aleš; Dembitský, V. M.

2003-01-01

Roč. 48, č. 1 (2003), s. 71-75 ISSN 0015-5632 Institutional research plan: CEZ:AV0Z5020903 Keywords : cyanobacterial spcies * freshwater wild Subject RIV: EE - Microbiology, Virology Impact factor: 0.857, year: 2003

Mitigating cyanobacterial blooms: how effective are 'effective microorganisms'?

NARCIS (Netherlands)

Lürling, M.F.L.L.W.; Tolman, Y.; Euwe, M.

2009-01-01

This study examined the effects of 'Effective Microorganisms (EM)' on the growth of cyanobacteria, and their ability to terminate cyanobacterial blooms. The EM was tested in the form of 'mudballs' or 'Bokashi-balls', and as a suspension (EM-A) in laboratory experiments. No growth inhibition was

Cyanobacterial Community Structure In Lithifying Mats of A Yellowstone Hotspring-Implications for Precambrian Stromatolite Biocomplexity

Science.gov (United States)

Lau, Evan; Nash, C. Z.; Vogler, D. R.; Cullings, K.; DeVincenzi, Donald (Technical Monitor)

2002-01-01

Denaturing Gradient Gel Electrophoresis (DGGE) of partial 16S rRNA gene sequences was used to investigate the molecular biodiversity of cyanobacterial communities inhabiting various lithified morpho-structures in two hotsprings of Yellowstone National Park. These morpho-structures - flat-topped columns, columnar cones, and ridged cones - resemble ancient stromatolites, which are possibly biogenic in origin. The top, middle and bottom sections of these lithified morpho-structures, as well as surrounding non-lithified mats were analyzed to determine the vertical and spatial distribution of cyanobacterial communities. Results from DGGE indicate that the cyanobacterial community composition of lithified morpho-structures (flat-topped columns, columnar cones, and ridged cones) were largely similar in vertical distribution as well as among the morpho-structures being studied. Preliminary results indicate that the cyanobacterial communities in these lithified morpho-structures were significantly different from communities in surrounding non-lithified mats. These results provide additional support to the theory that certain Phormidium/Leptolyngbya species are involved in the morphogenesis of lithifying morpho-structures in hotsprings and may have played a role in the formation of ancient stromatolites.

Nutrient control of cyanobacterial blooms in the Baltic Sea

NARCIS (Netherlands)

Stal, L.J.; Staal, M.J.; Villbrandt, M.

1999-01-01

Cyanobacterial blooms in the Baltic Sea were investigated with respect to growth Limitation and nitrogen fixation. The community was composed predominantly of Synechococcus spp., and large, heterocystous, nitrogen-fixing cyanobacteria (Aphanizomenon spp, and Nodularia spp.), that usually formed

Cyanobacterial populations in biological soil crusts of the northwest Negev Desert, Israel - effects of local conditions and disturbance.

Science.gov (United States)

Hagemann, Martin; Henneberg, Manja; Felde, Vincent J M N L; Berkowicz, Simon M; Raanan, Hagai; Pade, Nadin; Felix-Henningsen, Peter; Kaplan, Aaron

2016-11-02

Biological soil crusts (BSCs) fulfill numerous ecological functions in arid and semiarid areas. Cyanobacteria are important BSC organisms, which are responsible for carbon fixation, N 2 -fixation, and binding of soil via extracellular polysaccharides. The cyanobacterial populations were characterized in different sampling plots established in three experimental stations along a rainfall gradient within NW Negev Desert, Israel. Cyanobacterial crust thickness and osmolyte accumulation therein decreased in plots with lower moisture. The cyanobacterial population structure also changed in different plots. We observed an increase of subsection III cyanobacteria such as Microcoleus spp. and Leptolyngbya sp. and a decreasing proportion of strains belonging to subsections I and IV in drier areas on the rainfall gradient. This population shift was also observed in the sampling plots, which were situated at various relief positions within the sand dune experimental sites. We also characterized the cyanobacterial populations within mechanically disturbed plots. After four years, they reached between 80 and 50% of the control populations in the northern-most and southern stations, respectively. Our results suggest that the cyanobacterial population is sensitive not only to macroscale factors but may also be subject to local climate variations and that four years were insufficient for complete recovery of the cyanobacterial population. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Combined exposure of carps (Cyprinus carpio L.) to cyanobacterial biomass and white spot disease.

Science.gov (United States)

Palikova, Miroslava; Navratil, Stanislav; Papezikova, Ivana; Ambroz, Petr; Vesely, Tomas; Pokorova, Dagmar; Mares, Jan; Adamovsky, Ondrej; Navratil, Lukas; Kopp, Radovan

2012-01-01

Under environmental conditions, fish can be exposed to multiple stressors including natural toxins and infectious agents at the same time. This study brings new knowledge on the effects of controlled exposure to multiple stressors in fish. The aim of this study was to test the hypothesis that influence of cyanobacterial biomass and an infection agent represented by the white spot disease can combine to enhance the effects on fish. Common carps were divided into four groups, each with 40 specimens for 20 days: control group, cyanobacterial biomass exposed group, Ichthyophthirius multifiliis-infected fish (Ich) and cyanobacterial biomass-exposed fish + Ichthyophthirius multifiliis-infected fish. During the experiment we evaluated the clinical signs, mortality, selected haematological parameters, immune parameters and toxin accumulation. There was no mortality in control fish and cyanobacterial biomass-exposed fish. One specimen died in Ichthyophthirius multifiliis-infected fish and the combined exposure resulted in the death of 13 specimens. The whole leukocyte counts (WBC) of the control group did not show any significant differences. Cyanobacteria alone caused a significant increase of the WBC on day 13 (p≤0.05) and on day 20 (p≤0.01). Also, I. multifiliis caused a significant elevation of WBC (p≤0.01) on day 20. Co-exposition resulted in WBC increased on day 13 and decrease on day 20, but the changes were not significant. It is evident from the differential leukocyte counts that while the increase of WBC in the group exposed to cyanobacteria was caused by elevation of lymphocytes, the increase in the group infected by I. multifiliis was due to the increase of myeloid cells. It well corresponds with the integral of chemiluminescence in the group infected by I. multifiliis, which is significantly elevated on day 20 in comparison with all other groups. We can confirm additive action of different agents on the immune system of fish. While single agents seemed to

Cyanobacterial composition of microbial mats from an Australian thermal spring: a polyphasic evaluation.

Science.gov (United States)

McGregor, Glenn B; Rasmussen, J Paul

2008-01-01

Cyanobacterial composition of microbial mats from an alkaline thermal spring issuing at 43-71 degrees C from tropical north-eastern Australia are described using a polyphasic approach. Eight genera and 10 species from three cyanobacterial orders were identified based on morphological characters. These represented taxa previously known as thermophilic from other continents. Ultrastructural analysis of the tower mats revealed two filamentous morphotypes contributed the majority of the biomass. Both types had ultrastructural characteristics of the family Pseudanabaenaceae. DNA extracts were made from sections of the tentaculiform towers and the microbial community analysed by 16S cyanobacteria-specific PCR and denaturing-gradient gel electrophoresis. Five significant bands were identified and sequenced. Two bands clustered closely with Oscillatoria amphigranulata isolated from New Zealand hot springs; one unique phylotype had only moderate similarity to a range of Leptolyngbya species; and one phylotype was closely related to a number of Geitlerinema species. Generally the approaches yielded complementary information, however the results suggest that species designation based on morphological and ultrastructural criteria alone often fails to recognize their true phylogenetic position. Conversely some molecular techniques may fail to detect rare taxa suggesting that the widest possible suite of techniques be applied when conducting analyses of cyanobacterial diversity of natural populations. This is the first polyphasic evaluation of thermophilic cyanobacterial communities from the Australian continent.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

NARCIS (Netherlands)

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma; Cillero-Castro, Carmen; Budzyńska, Agnieszka; Goldyn, Ryszard; Kozak, Anna; Rosińska, Joanna; Szeląg-Wasielewska, Elżbieta; Domek, Piotr; Jakubowska-Krepska, Natalia; Kwasizur, Kinga; Messyasz, Beata; Pełechaty, Aleksandra; Pełechaty, Mariusz; Kokocinski, Mikolaj; García-Murcia, Ana; Real, Monserrat; Romans, Elvira; Noguero-Ribes, Jordi; Duque, David Parreño; Fernández-Morán, Elísabeth; Karakaya, Nusret; Häggqvist, Kerstin; Demir, Nilsun; Beklioğlu, Meryem; Filiz, Nur; Levi, Eti E.; Iskin, Uğur; Bezirci, Gizem; Tavşanoğlu, Ülkü Nihan; Özhan, Koray; Gkelis, Spyros; Panou, Manthos; Fakioglu, Özden; Avagianos, Christos; Kaloudis, Triantafyllos; Çelik, Kemal; Yilmaz, Mete; Marcé, Rafael; Catalán, Nuria; Bravo, Andrea G.; Buck, Moritz; Colom-Montero, William; Mustonen, Kristiina; Pierson, Don; Yang, Yang; Raposeiro, Pedro M.; Gonçalves, Vítor; Antoniou, Maria G.; Tsiarta, Nikoletta; McCarthy, Valerie; Perello, Victor C.; Feldmann, Tõnu; Laas, Alo; Panksep, Kristel; Tuvikene, Lea; Gagala, Ilona; Mankiewicz-Boczek, Joana; Yağcı, Meral Apaydın; Çınar, Şakir; Çapkın, Kadir; Yağcı, Abdulkadir; Cesur, Mehmet; Bilgin, Fuat; Bulut, Cafer; Uysal, Rahmi; Obertegger, Ulrike; Boscaini, Adriano; Flaim, Giovanna; Salmaso, Nico; Cerasino, Leonardo; Richardson, Jessica; Visser, Petra M; Verspagen, Jolanda M. H.; Karan, Tünay; Soylu, Elif Neyran; Maraşlıoğlu, Faruk; Napiórkowska-Krzebietke, Agnieszka; Ochocka, Agnieszka; Pasztaleniec, Agnieszka; Antão-Geraldes, Ana M.; Vasconcelos, Vitor; Morais, João; Vale, Micaela; Köker, Latife; Akçaalan, Reyhan; Albay, Meriç; Špoljarić Maronić, Dubravka; Stević, Filip; Žuna Pfeiffer, Tanja; Fonvielle, Jeremy; Straile, Dietmar; Rothhaupt, Karl-Otto; Hansson, Lars-Anders; Urrutia-Cordero, Pablo; Bláha, Luděk; Geriš, Rodan; Fránková, Markéta; Koçer, Mehmet Ali Turan; Alp, Mehmet Tahir; Remec-Rekar, Spela; Elersek, Tina; Triantis, Theodoros; Zervou, Sevasti-Kiriaki; Hiskia, Anastasia; Haande, Sigrid; Skjelbred, Birger; Madrecka, Beata; Nemova, Hana; Drastichova, Iveta; Chomova, Lucia; Edwards, Christine; Sevindik, Tuğba Ongun; Tunca, Hatice; Önem, Burçin; Aleksovski, Boris; Krstić, Svetislav; Vucelić, Itana Bokan; Nawrocka, Lidia; Salmi, Pauliina; Machado-Vieira, Danielle; de Oliveira, Alinne Gurjão; Delgado-Martín, Jordi; García-García, David; Cereijo, Jose Luís; Gomà, Joan; Trapote, Mari Carmen; Vegas-Vilarrúbia, Teresa; Obrador, Biel; Grabowska, Magdalena; Karpowicz, Maciej; Chmura, Damian; Úbeda, Bárbara; Gálvez, José Ángel; Özen, Arda; Christoffersen, Kirsten Seestern; Warming, Trine Perlt; Kobos, Justyna; Mazur-Marzec, Hanna; Pérez-Martínez, Carmen; Ramos-Rodríguez, Eloísa; Arvola, Lauri; Alcaraz-Párraga, Pablo; Toporowska, Magdalena; Pawlik-Skowronska, Barbara; Niedźwiecki, Michał; Pęczuła, Wojciech; Leira, Manel; Hernández, Armand; Moreno-Ostos, Enrique; Blanco, José María; Rodríguez, Valeriano; Montes-Pérez, Jorge Juan; Palomino, Roberto L.; Rodríguez-Pérez, Estela; Carballeira, Rafael; Camacho, Antonio; Picazo, Antonio; Rochera, Carlos; Santamans, Anna C.; Ferriol, Carmen; Romo, Susana; Soria, Juan Miguel; Dunalska, Julita; Sieńska, Justyna; Szymański, Daniel; Kruk, Marek; Kostrzewska-Szlakowska, Iwona; Jasser, Iwona; Žutinić, Petar; Gligora Udovič, Marija; Plenković-Moraj, Anđelka; Frąk, Magdalena; Bańkowska-Sobczak, Agnieszka; Wasilewicz, Michał; Özkan, Korhan; Maliaka, Valentini; Kangro, Kersti; Grossart, Hans-Peter; Paerl, Hans W.; Carey, Cayelan C.; Ibelings, Bas W.

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and

Effect of Environmental Factors on Cyanobacterial Abundance and Cyanotoxins Production in Natural and Drinking Water, Bangladesh.

Science.gov (United States)

Affan, Abu; Khomavis, Hisham S; Al-Harbi, Salim Marzoog; Haque, Mahfuzul; Khan, Saleha

2015-02-01

Cyanobacterial blooms commonly appear during the summer months in ponds, lakes and reservoirs in Bangladesh. In these areas, fish mortality, odorous water and fish and human skin irritation and eye inflammation have been reported. The influence of physicochemical factors on the occurrence of cyanobacteria and its toxin levels were evaluated in natural and drinking water in Bangladesh. A highly sensitive immunosorbent assay was used to detect microcystins (MCs). Cyanobacteria were found in 22 of 23 samples and the dominant species were Microcystis aeruginosa, followed by Microcystisflosaquae, Anabeana crassa and Aphanizomenon flosaquae. Cyanobacterial abundance varied from 39 to 1315 x 10(3) cells mL(-1) in natural water and 31 to 49 x 10(3) cells mL(-1) in tap water. MC concentrations were 25-82300 pg mL(-1) with the highest value measured in the fish research pond, followed by Ishakha Lake. In tap water, MC concentrations ranged from 30-32 pg mL(-1). The correlation between nitrate-nitrogen (NO3-N) concentration and cyanobacterial cell abundance was R2 = 0.62 while that between cyanobacterial abundance and MC concentration was R2 = 0.98. The increased NO3-N from fish feed, organic manure, poultry and dairy farm waste and fertilizer from agricultural land eutrophicated the water bodies and triggered cyanobacterial bloom formation. The increased amount of cyanobacteria produced MCs, subsequently reducing the water quality.

The presence of the cyanobacterial toxin microcystin in black band disease of corals.

Science.gov (United States)

Richardson, Laurie L; Sekar, Raju; Myers, Jamie L; Gantar, Miroslav; Voss, Joshua D; Kaczmarsky, Longin; Remily, Elizabeth R; Boyer, Gregory L; Zimba, Paul V

2007-07-01

Black band disease (BBD) is a migrating, cyanobacterial dominated, sulfide-rich microbial mat that moves across coral colonies lysing coral tissue. While it is known that BBD sulfate-reducing bacteria contribute to BBD pathogenicity by production of sulfide, additional mechanisms of toxicity may be involved. Using HPLC/MS, the cyanotoxin microcystin was detected in 22 field samples of BBD collected from five coral species on nine reefs of the wider Caribbean (Florida Keys and Bahamas). Two cyanobacterial cultures isolated from BBD, Geitlerinema and Leptolyngbya sp. contained microcystin based on HPLC/MS, with toxic activity confirmed using the protein phosphatase inhibition assay. The gene mcyA from the microcystin synthesis complex was detected in two field samples and from both BBD cyanobacterial cultures. Microcystin was not detected in six BBD samples from a different area of the Caribbean (St Croix, USVI) and the Philippines, suggesting regional specificity for BBD microcystin. This is the first report of the presence of microcystin in a coral disease.

Late Archean mineralised cyanobacterial mats and their modern analogs

Science.gov (United States)

Kazmierczak, J.; Altermann, W.; Kremer, B.; Kempe, S.; Eriksson, P. G.

2008-09-01

,c) reminiscent of common sheaths (glycocalix), typical for coccoidal colonial (pseudoparenchymatous) entophysalidacean or pleurocapsalean cyanobacteria (Fig. 2d-f). The remains of the coccoid sheaths and capsules are visible as a system of rimmed subglobular or irregularly polygonal pits separated from adjacent pits by 2-3 μm thick walls. Microprobe analyses show that the interiors of the pits are composed of almost pure calcium carbonate whereas the rims and walls of calcium carbonate with high admixture of silicates (mostly Al-Fe clay-like silicates) and dolomite. High magnification images of rims and walls confirm the microprobe data indicating authigenic character of the minerals forming both the carbonate infilling the pits interiors (CaCO3) and their rims and walls (CaCO3 + Al-Fe silicates + dolomite). EPSC Abstracts, Vol. 3, EPSC2008-A-00493, 2008 European Planetary Science Congress, Author(s) 2008 It seems that carbonates were the first mineral phase filling the spaces remained after the plasmolysis of the cyanobacterial cell contents, whereas the formation of silicates within the exopolysaccharides forming the bulk of the sheaths and capsules was a later diagenetic process. Microprobe analyses of mineralised modern coccoid cyanobacterial mats forming tower-like structures in the highly alkaline Lake Van, Turkey [3,4] display a set of elements indicative for the presence of authigenic carbonate and silicate minerals which are almost identical with that occurring in the studied Neoarchean samples. Also the optical and SEM images of polished and etched platelets of permineralised Lake Van microbialites are strikingly similar (Fig. 2d-f). Similarly as in modern cyanobacterial and other microbial mats, the process of early post mortem mineralisation, in the case of the Nauga Formation, was most probably associated with the action of heterotrophic bacteria upon the dead cyanobacterial biomass. Heterotrophic bacteria occupying EPS layers of living and dead cyanobacterial

The genome and structural proteome of an ocean siphovirus: a new window into the cyanobacterial 'mobilome'.

Science.gov (United States)

Sullivan, Matthew B; Krastins, Bryan; Hughes, Jennifer L; Kelly, Libusha; Chase, Michael; Sarracino, David; Chisholm, Sallie W

2009-11-01

Prochlorococcus, an abundant phototroph in the oceans, are infected by members of three families of viruses: myo-, podo- and siphoviruses. Genomes of myo- and podoviruses isolated on Prochlorococcus contain DNA replication machinery and virion structural genes homologous to those from coliphages T4 and T7 respectively. They also contain a suite of genes of cyanobacterial origin, most notably photosynthesis genes, which are expressed during infection and appear integral to the evolutionary trajectory of both host and phage. Here we present the first genome of a cyanobacterial siphovirus, P-SS2, which was isolated from Atlantic slope waters using a Prochlorococcus host (MIT9313). The P-SS2 genome is larger than, and considerably divergent from, previously sequenced siphoviruses. It appears most closely related to lambdoid siphoviruses, with which it shares 13 functional homologues. The approximately 108 kb P-SS2 genome encodes 131 predicted proteins and notably lacks photosynthesis genes which have consistently been found in other marine cyanophage, but does contain 14 other cyanobacterial homologues. While only six structural proteins were identified from the genome sequence, 35 proteins were detected experimentally; these mapped onto capsid and tail structural modules in the genome. P-SS2 is potentially capable of integration into its host as inferred from bioinformatically identified genetic machinery int, bet, exo and a 53 bp attachment site. The host attachment site appears to be a genomic island that is tied to insertion sequence (IS) activity that could facilitate mobility of a gene involved in the nitrogen-stress response. The homologous region and a secondary IS-element hot-spot in Synechococcus RS9917 are further evidence of IS-mediated genome evolution coincident with a probable relic prophage integration event. This siphovirus genome provides a glimpse into the biology of a deep-photic zone phage as well as the ocean cyanobacterial prophage and IS element

Chlorophyll f distribution and dynamics in cyanobacterial beachrock biofilms.

Science.gov (United States)

Trampe, Erik; Kühl, Michael

2016-12-01

Chlorophyll (Chl) f, the most far-red (720-740 nm) absorbing Chl species, was discovered in cyanobacterial isolates from stromatolites and subsequently in other habitats as well. However, the spatial distribution and temporal dynamics of Chl f in a natural habitat have so far not been documented. Here, we report the presence of Chl f in cyanobacterial beachrock biofilms. Hyperspectral imaging on cross-sections of beachrock from Heron Island (Great Barrier Reef, Australia), showed a strong and widely distributed signature of Chl f absorption in an endolithic layer below the dense cyanobacterial surface biofilm that could be localized to aggregates of Chroococcidiopsis-like unicellular cyanobacteria packed within a thick common sheath. High-pressure liquid chromatography-based pigment analyses showed in situ ratios of Chl f to Chl a of 5% in brown-pigmented zones of the beachrock, with lower ratios of ~0.5% in the black- and pink-pigmented biofilm zones. Enrichment experiments with black beachrock biofilm showed stimulated synthesis of Chl f and Chl d when grown under near-infrared radiation (NIR; 740 nm), with a Chl f to Chl a ratio increasing 4-fold to 2%, whereas the Chl d to Chl a ratio went from 0% to 0.8%. Enrichments grown under white light (400-700 nm) produced no detectable amounts of either Chl d or Chl f. Beachrock cyanobacteria thus exhibited characteristics of far-red light photoacclimation, enabling Chl f -containing cyanobacteria to thrive in optical niches deprived of visible light when sufficient NIR is prevalent. © 2016 Phycological Society of America.

A single phosphorus treatment doubles growth of cyanobacterial lichen transplants.

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McCune, Bruce; Caldwell, Bruce A

2009-02-01

Lichens are reputedly slow growing and become unhealthy or die in response to supplements of the usual limiting resources, such as water and nitrogen. We found, however, that the tripartite cyanobacterial lichen Lobaria pulmonaria doubled in annual biomass growth after a single 20-minute immersion in a phosphorus solution (K2HPO4), as compared to controls receiving no supplemental phosphorus. This stimulation of cyanolichens by phosphorus has direct relevance to community and population ecology of lichens, including improving models of lichen performance in relation to air quality, improving forest management practices affecting old-growth associated cyanolichens, and understanding the distribution and abundance of cyanolichens on the landscape. Phosphorus may be as important a stimulant to cyanobacterial-rich lichen communities as it is to cyanobacteria in aquatic ecosystems.

Inhibition of gap-junctional intercellular communication and activation of mitogen-activated protein kinases by cyanobacterial extracts--indications of novel tumor-promoting cyanotoxins?

Science.gov (United States)

Bláha, Ludĕk; Babica, Pavel; Hilscherová, Klára; Upham, Brad L

2010-01-01

Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.

Temporal variation in community composition, pigmentation, and Fv/Fm of desert cyanobacterial soil crusts

Science.gov (United States)

Bowker, M.A.; Reed, S.C.; Belnap, J.; Phillips, S.L.

2002-01-01

Summers on the Colorado Plateau (USA) are typified by harsh conditions such as high temperatures, brief soil hydration periods, and high UV and visible radiation. We investigated whether community composition, physiological status, and pigmentation might vary in biological soil crusts as a result of such conditions. Representative surface cores were sampled at the ENE, WSW, and top microaspects of 20 individual soil crust pedicels at a single site in Canyonlands National Park, Utah, in spring and fall of 1999. Frequency of cyanobacterial taxa, pigment concentrations, and dark adapted quantum yield (Fv/Fm) were measured for each core. The frequency of major cyanobacterial taxa was lower in the fall compared to spring. The less-pigmented cyanobacterium Microcoleus vaginatus showed significant mortality when not in the presence of Nostoc spp. and Scytonema myochrous (Dillw.) Agardh. (both synthesizers of UV radiation-linked pigments) but had little or no mortality when these species were abundant. We hypothesize that the sunscreen pigments produced by Nostoc and Scytonema in the surface of crusts protect other, less-pigmented taxa. When fall and spring samples were compared, overall cyanobacterial frequency was lower in fall, while sunscreen pigment concentrations, chlorophyll a concentration, and Fv/Fm were higher in fall. The ratio of cyanobacterial frequency/chlorophyll a concentrations was 2-3 times lower in fall than spring. Because chlorophyll a is commonly used as a surrogate measure of soil cyanobacterial biomass, these results indicate that seasonality needs to be taken into consideration. In the fall sample, most pigments associated with UV radiation protection or repair were at their highest concentrations on pedicel tops and WSW microaspects, and at their lowest concentrations on ENE microaspects. We suggest that differential pigment concentrations between microaspects are induced by varying UV radiation dosage at the soil surface on these different

Contributions of meteorology to the phenology of cyanobacterial blooms: implications for future climate change.

Science.gov (United States)

Zhang, Min; Duan, Hongtao; Shi, Xiaoli; Yu, Yang; Kong, Fanxiang

2012-02-01

Cyanobacterial blooms are often a result of eutrophication. Recently, however, their expansion has also been found to be associated with changes in climate. To elucidate the effects of climatic variables on the expansion of cyanobacterial blooms in Taihu, China, we analyzed the relationships between climatic variables and bloom events which were retrieved by satellite images. We then assessed the contribution of each climate variable to the phenology of blooms using multiple regression models. Our study demonstrates that retrieving ecological information from satellite images is meritorious for large-scale and long-term ecological research in freshwater ecosystems. Our results show that the phenological changes of blooms at an inter-annual scale are strongly linked to climate in Taihu during the past 23 yr. Cyanobacterial blooms occur earlier and last longer with the increase of temperature, sunshine hours, and global radiation and the decrease of wind speed. Furthermore, the duration increases when the daily averages of maximum, mean, and minimum temperature each exceed 20.3 °C, 16.7 °C, and 13.7 °C, respectively. Among these factors, sunshine hours and wind speed are the primary contributors to the onset of the blooms, explaining 84.6% of their variability over the past 23 yr. These factors are also good predictors of the variability in the duration of annual blooms and determined 58.9% of the variability in this parameter. Our results indicate that when nutrients are in sufficiently high quantities to sustain the formation of cyanobacterial blooms, climatic variables become crucial in predicting cyanobacterial bloom events. Climate changes should be considered when we evaluate how much the amount of nutrients should be reduced in Taihu for lake management. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phosphonate degradation by Spirulina strains: cyanobacterial biofilters for the removal of anticorrosive polyphosphonates from wastewater.

Science.gov (United States)

Forlani, Giuseppe; Prearo, Valentina; Wieczorek, Dorota; Kafarski, Paweł; Lipok, Jacek

2011-03-07

The ability of Spirulina spp. to metabolize the recalcitrant xenobiotic Dequest 2054(®) [hexamethylenediamine-N,N,N',N'-tetrakis(methylphosphonic acid)], a CaSO(4) inhibitor used for boiler treatment and reverse osmosis desalination, was investigated. The compound served as sole source of phosphorus, but not of nitrogen, for cyanobacterial growth. In vivo utilization was followed by (31)P NMR analysis. The disappearance of the polyphosphonate proceeded only with actively dividing cells, and no release of inorganic phosphate was evident. However, no difference was found between P-starved and P-fed cultures. Maximal utilization reached 1.0 ± 0.2 mmoll(-1), corresponding to 0.56 ± 0.11 mmol g(-1) dry biomass, thus residual amounts were still present in the exhausted medium when the compound was supplied at higher initial concentrations. At low substrate levels metabolism rates were lower, suggesting that a concentration-driven uptake may represent a limiting step during the biodegradation process. The compound was not retained by biocolumns made with immobilized cyanobacterial cells, either alive or dead. A lab-scale pilot plant, consisting of a series of sequentially connected vessels containing an actively proliferating algal culture, was built and tested for wastewater treatment. Results showed 50% removal of the polyphosphonate added to an initial concentration of 2.5mM. Although further optimization will be required, data strengthen the possibility of using cyanobacterial strains for bioremediation purposes. Copyright © 2010 Elsevier Inc. All rights reserved.

Chasing after Non-cyanobacterial Nitrogen Fixation in Marine Pelagic Environments

Directory of Open Access Journals (Sweden)

Pia H. Moisander

2017-09-01

Full Text Available Traditionally, cyanobacterial activity in oceanic photic layers was considered responsible for the marine pelagic dinitrogen (N2 fixation. Other potentially N2-fixing bacteria and archaea have also been detected in the pelagic water column, however, the activity and importance of these non-cyanobacterial diazotrophs (NCDs remain poorly constrained. In this perspective we summarize the N2 fixation rates from recently published studies on photic and aphotic layers that have been attributed to NCD activity via parallel molecular measurements, and discuss the status, challenges, and data gaps in estimating non-cyanobacterial N2 fixation NCNF in the ocean. Rates attributed to NCNF have generally been near the detection limit thus far (<1 nmol N L−1 d−1. Yet, if considering the large volume of the dark ocean, even low rates of NCNF could make a significant contribution to the new nitrogen input to the ocean. The synthesis here shows that nifH transcription data for NCDs have been reported in only a few studies where N2 fixation rates were detected in the absence of diazotrophic cyanobacteria. In addition, high apparent diversity and regional variability in the NCDs complicate investigations of these communities. Future studies should focus on further investigating impacts of environmental drivers including oxygen, dissolved organic matter, and dissolved inorganic nitrogen on NCNF. Describing the ecology of NCDs and accurately measuring NCNF rates, are critical for a future evaluation of the contribution of NCNF to the marine nitrogen budget.

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming

2014-04-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge\\'s mild intercellular environment. 2014 Gao et al.

Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

KAUST Repository

Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Bajic, Vladimir B.; Qian, Pei-Yuan

2014-01-01

"Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. 2014 Gao et al.

Rapid reactivation of cyanobacterial photosynthesis and migration upon rehydration of desiccated marine microbial mats

Directory of Open Access Journals (Sweden)

Arjun eChennu

2015-12-01

Full Text Available Desiccated cyanobacterial mats are the dominant biological feature in the Earth's arid zones. While the response of desiccated cyanobacteria to rehydration is well documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 minutes after rehydration chlorophyll a concentrations increased 2-5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min – 48 h involved migration of the reactivated cyanobacteria towards the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and aquatic origin. However the response of upward migration and its triggering factor appears to be mat-specific and likely linked to other factors.

Rapid Reactivation of Cyanobacterial Photosynthesis and Migration upon Rehydration of Desiccated Marine Microbial Mats

KAUST Repository

Chennu, Arjun

2015-12-24

Desiccated cyanobacterial mats are the dominant biological feature in the Earth’s arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors, and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 min after rehydration chlorophyll a concentrations increased 2–5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min–48 h) involved migration of the reactivated cyanobacteria toward the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and marine origin. However, the response of upward migration and its triggering factor appear to be mat-specific and likely linked to other factors.

Rapid Reactivation of Cyanobacterial Photosynthesis and Migration upon Rehydration of Desiccated Marine Microbial Mats

KAUST Repository

Chennu, Arjun; Grinham, Alistair; Polerecky, Lubos; de Beer, Dirk; Alnajjar, Mohammad Ahmad

2015-01-01

Desiccated cyanobacterial mats are the dominant biological feature in the Earth’s arid zones. While the response of desiccated cyanobacteria to rehydration is well-documented for terrestrial systems, information about the response in marine systems is lacking. We used high temporal resolution hyperspectral imaging, liquid chromatography, pulse-amplitude fluorometry, oxygen microsensors, and confocal laser microscopy to study this response in a desiccated microbial mat from Exmouth Gulf, Australia. During the initial 15 min after rehydration chlorophyll a concentrations increased 2–5 fold and cyanobacterial photosynthesis was re-established. Although the mechanism behind this rapid increase of chlorophyll a remains unknown, we hypothesize that it involves resynthesis from a precursor stored in desiccated cyanobacteria. The subsequent phase (15 min–48 h) involved migration of the reactivated cyanobacteria toward the mat surface, which led, together with a gradual increase in chlorophyll a, to a further increase in photosynthesis. We conclude that the response involving an increase in chlorophyll a and recovery of photosynthetic activity within minutes after rehydration is common for cyanobacteria from desiccated mats of both terrestrial and marine origin. However, the response of upward migration and its triggering factor appear to be mat-specific and likely linked to other factors.

An algorithm for detecting trophic status (chlorophyll-a), cyanobacterial-dominance, surface scums and floating vegetation in inland and coastal waters

CSIR Research Space (South Africa)

Matthews, MW

2012-09-01

Full Text Available A novel algorithm is presented for detecting trophic status (chlorophyll-a), cyanobacterial blooms (cyano-blooms), surface scum and floating vegetation in coastal and inland waters using top-ofatmosphere data from the Medium Resolution Imaging...

Limnology and cyanobacterial diversity of high altitude lakes of ...

Indian Academy of Sciences (India)

Limnological data of four high altitude lakes from the cold desert region of Himachal Pradesh, India, has been correlated with cyanobacterial diversity. Physico-chemical characteristics and nutrient contents of the studied lakes revealed that Sissu Lake is mesotrophic while Chandra Tal, Suraj Tal and Deepak Tal are ...

Hydrogen from Water in a Novel Recombinant Cyanobacterial System

Energy Technology Data Exchange (ETDEWEB)

Weyman, Philip D [J. Craig Venter Institute; Smith, Hamillton O.

2014-12-03

Photobiological processes are attractive routes to renewable H2 production. With the input of solar energy, photosynthetic microbes such as cyanobacteria and green algae carry out oxygenic photosynthesis, using sunlight energy to extract protons and high energy electrons from water. These protons and high energy electrons can be fed to a hydrogenase system yielding H2. However, most hydrogen-evolving hydrogenases are inhibited by O2, which is an inherent byproduct of oxygenic photosynthesis. The rate of H2 production is thus limited. Certain photosynthetic bacteria are reported to have an O2-tolerant evolving hydrogenase, yet these microbes do not split water, and require other more expensive feedstocks. To overcome these difficulties, the goal of this work has been to construct novel microbial hybrids by genetically transferring O2-tolerant hydrogenases from other bacteria into a class of photosynthetic bacteria called cyanobacteria. These hybrid organisms will use the photosynthetic machinery of the cyanobacterial hosts to perform the water-oxidation reaction with the input of solar energy, and couple the resulting protons and high energy electrons to the O2-tolerant bacterial hydrogenase, all within the same microbe (Fig. 1). The ultimate goal of this work has been to overcome the sensitivity of the hydrogenase enzyme to O2 and address one of the key technological hurdles to cost-effective photobiological H2 production which currently limits the production of hydrogen in algal systems. In pursuit of this goal, work on this project has successfully completed many subtasks leading to a greatly increased understanding of the complicated [NiFe]-hydrogenase enzymes. At the beginning of this project, [NiFe] hydrogenases had never been successfully moved across wide species barriers and had never been heterologously expressed in cyanobacteria. Furthermore, the idea that whole, functional genes could be extracted from complicated, mixed-sequence meta-genomes was not

The genome and structural proteome of an ocean siphovirus: a new window into the cyanobacterial ‘mobilome’

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Sullivan, Matthew B; Krastins, Bryan; Hughes, Jennifer L; Kelly, Libusha; Chase, Michael; Sarracino, David; Chisholm, Sallie W

2009-01-01

Prochlorococcus, an abundant phototroph in the oceans, are infected by members of three families of viruses: myo-, podo- and siphoviruses. Genomes of myo- and podoviruses isolated on Prochlorococcus contain DNA replication machinery and virion structural genes homologous to those from coliphages T4 and T7 respectively. They also contain a suite of genes of cyanobacterial origin, most notably photosynthesis genes, which are expressed during infection and appear integral to the evolutionary trajectory of both host and phage. Here we present the first genome of a cyanobacterial siphovirus, P-SS2, which was isolated from Atlantic slope waters using a Prochlorococcus host (MIT9313). The P-SS2 genome is larger than, and considerably divergent from, previously sequenced siphoviruses. It appears most closely related to lambdoid siphoviruses, with which it shares 13 functional homologues. The ∼108 kb P-SS2 genome encodes 131 predicted proteins and notably lacks photosynthesis genes which have consistently been found in other marine cyanophage, but does contain 14 other cyanobacterial homologues. While only six structural proteins were identified from the genome sequence, 35 proteins were detected experimentally; these mapped onto capsid and tail structural modules in the genome. P-SS2 is potentially capable of integration into its host as inferred from bioinformatically identified genetic machinery int, bet, exo and a 53 bp attachment site. The host attachment site appears to be a genomic island that is tied to insertion sequence (IS) activity that could facilitate mobility of a gene involved in the nitrogen-stress response. The homologous region and a secondary IS-element hot-spot in Synechococcus RS9917 are further evidence of IS-mediated genome evolution coincident with a probable relic prophage integration event. This siphovirus genome provides a glimpse into the biology of a deep-photic zone phage as well as the ocean cyanobacterial prophage and IS element �

Cyanotoxin mixtures and taste-and-odor compounds in cyanobacterial blooms from the midwestern united states

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Graham, J.L.; Loftin, K.A.; Meyer, M.T.; Ziegler, A.C.

2010-01-01

The mixtures of toxins and taste-and-odor compounds present during cyanobacterial blooms are not well characterized and of particular concern when evaluating potential human health risks. Cyanobacterial blooms were sampled in twenty-three Midwestern United States lakes and analyzed for community composition, thirteen cyanotoxins by liquid chromatography/mass spectrometry and immunoassay, and two taste-and-odor compounds by gas chromatography/mass spectrometry. Aphanizomenon, Cylindrospermopsis and/or Microcystis were dominant in most (96%) blooms, but community composition was not strongly correlated with toxin and taste-and-odor occurrence. Microcystins occurred in all blooms. Total microcystin concentrations measured by liquid chromatography/mass spectrometry and immunoassay were linearly related (rs = 0.76, p cyanotoxins occurred in 48% of blooms and 95% had multiple microcystin variants. Toxins and taste-and-odor compounds frequently co-occurred (91% of blooms), indicating odor may serve as a warning that cyanotoxins likely are present. However, toxins occurred more frequently than taste-and-odor compounds, so odor alone does not provide sufficient warning to ensure human-health protection. ?? This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society.

On the use of high-throughput sequencing for the study of cyanobacterial diversity in Antarctic aquatic mats.

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Pessi, Igor Stelmach; Maalouf, Pedro De Carvalho; Laughinghouse, Haywood Dail; Baurain, Denis; Wilmotte, Annick

2016-06-01

The study of Antarctic cyanobacterial diversity has been mostly limited to morphological identification and traditional molecular techniques. High-throughput sequencing (HTS) allows a much better understanding of microbial distribution in the environment, but its application is hampered by several methodological and analytical challenges. In this work, we explored the use of HTS as a tool for the study of cyanobacterial diversity in Antarctic aquatic mats. Our results highlight the importance of using artificial communities to validate the parameters of the bioinformatics procedure used to analyze natural communities, since pipeline-dependent biases had a strong effect on the observed community structures. Analysis of microbial mats from five Antarctic lakes and an aquatic biofilm from the Sub-Antarctic showed that HTS is a valuable tool for the assessment of cyanobacterial diversity. The majority of the operational taxonomic units retrieved were related to filamentous taxa such as Leptolyngbya and Phormidium, which are common genera in Antarctic lacustrine microbial mats. However, other phylotypes related to different taxa such as Geitlerinema, Pseudanabaena, Synechococcus, Chamaesiphon, Calothrix, and Coleodesmium were also found. Results revealed a much higher diversity than what had been reported using traditional methods and also highlighted remarkable differences between the cyanobacterial communities of the studied lakes. The aquatic biofilm from the Sub-Antarctic had a distinct cyanobacterial community from the Antarctic lakes, which in turn displayed a salinity-dependent community structure at the phylotype level. © 2016 Phycological Society of America.

A census of nuclear cyanobacterial recruits in the plant kingdom.

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Szabolcs Makai

Full Text Available The plastids and mitochondria of the eukaryotic cell are of endosymbiotic origin. These events occurred ~2 billion years ago and produced significant changes in the genomes of the host and the endosymbiont. Previous studies demonstrated that the invasion of land affected plastids and mitochondria differently and that the paths of mitochondrial integration differed between animals and plants. Other studies examined the reasons why a set of proteins remained encoded in the organelles and were not transferred to the nuclear genome. However, our understanding of the functional relations of the transferred genes is insufficient. In this paper, we report a high-throughput phylogenetic analysis to identify genes of cyanobacterial origin for plants of different levels of complexity: Arabidopsis thaliana, Chlamydomonas reinhardtii, Physcomitrella patens, Populus trichocarpa, Selaginella moellendorffii, Sorghum bicolor, Oryza sativa, and Ostreococcus tauri. Thus, a census of cyanobacterial gene recruits and a study of their function are presented to better understand the functional aspects of plastid symbiogenesis. From algae to angiosperms, the GO terms demonstrated a gradual expansion over functionally related genes in the nuclear genome, beginning with genes related to thylakoids and photosynthesis, followed by genes involved in metabolism, and finally with regulation-related genes, primarily in angiosperms. The results demonstrate that DNA is supplied to the nuclear genome on a permanent basis with no regard to function, and only what is needed is kept, which thereby expands on the GO space along the related genes.

Book review: Handbook of cyanobacterial monitoring and cyanotoxin analysis

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Graham, Jennifer L.; Loftin, Keith A.

2018-01-01

Review of Meriluoto, Jussi, Lisa Spoof, and GeoffreyA. Codd [eds.]. 2017. Handbook of Cyanobacterial Monitoring and Cyanotoxin Analysis. John Wiley & Sons, Ltd.: Chichester, West Sussex, UK, ISBN 978‐1‐119‐06868‐6 (978‐1‐119‐06876‐1 eBook), DOI 10.1002/9781119068761.

Insights from Cyanobacterial Genomes for the Development of Extraterrestrial Photoautotrophic Biotechnologies

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Brown, I. I.; Bryant, D. A.; Tringe, S. G.; Malley, K.; Sosa, O.; Sarkisova, S. A.; Garrison, D. H.; McKay, D. S.

2010-04-01

Using genomic and metagenomic analysis, Fe-tolerant cyanobacterial species with a large and diverse set of stress-tolerant genes, were identified as prime candidates for in situ resource utilization in a biogeoreactor at extraterrestrial outposts.

Proteomic approaches in research of cyanobacterial photosynthesis.

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Battchikova, Natalia; Angeleri, Martina; Aro, Eva-Mari

2015-10-01

Oxygenic photosynthesis in cyanobacteria, algae, and plants is carried out by a fabulous pigment-protein machinery that is amazingly complicated in structure and function. Many different approaches have been undertaken to characterize the most important aspects of photosynthesis, and proteomics has become the essential component in this research. Here we describe various methods which have been used in proteomic research of cyanobacteria, and demonstrate how proteomics is implemented into on-going studies of photosynthesis in cyanobacterial cells.

Multilocus and SSU rRNA gene phylogenetic analyses of available cyanobacterial genomes, and their relation to the current taxonomic system

Czech Academy of Sciences Publication Activity Database

Mareš, Jan

2018-01-01

Roč. 811, č. 1 (2018), s. 19-34 ISSN 0018-8158 R&D Projects: GA ČR(CZ) GA15-11912S Institutional support: RVO:67985939 Keywords : 16S rRNA * Cyanobacterial orders * Multilocus phylogeny Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 2.056, year: 2016

Modification of cyanobacterial bloom-derived biomass using potassium permanganate enhanced the removal of microcystins and adsorption capacity toward cadmium (II)

International Nuclear Information System (INIS)

Shao, Jihai; Gu, Ji-Dong; Peng, Liang; Luo, Si; Luo, Huili; Yan, Zhiyong; Wu, Genyi

2014-01-01

Highlights: • Potassium permanganate removed microcystins in the cyanobacterial bloom-derived biomass (CBDB). • Potassium permanganate oxidation caused the transformation of hydroxyl to carboxyl on the CBDB. • Manganese dioxide was formed on the surface of CBDB. • Potassium permanganate oxidation process increased the adsorption capacity of CBDB toward Cd(II). - Abstract: Cyanobacterial biomass shows high adsorption capacity toward heavy metal ions. However, the cyanotoxins in the cyanobacterial biomass inhibit its application in heavy metals removal. In order to safely and effectively remove Cd(II) from water using cyanobacterial bloom-derived biomass (CBDB), KMnO 4 was used to modify CBDB. The results indicated that the microcystins in the CBDB were successfully removed by KMnO 4 . Potassium permanganate oxidation caused the transformation of hydroxyl to carboxyl on the CBDB, and formed manganese dioxide on the surface of CBDB. The oxidized CBDB showed higher adsorption capacity toward Cd(II) than that of unoxidized treatment. The optimal KMnO 4 concentration for increasing the adsorption capacity of CBDB toward Cd(II) was 0.2 g/L. The adsorption isotherm of Cd(II) by oxidized- or unoxidized-CBDB was well fitted by Langmuir model, indicating that the adsorption of Cd(II) by CBDB was monolayer adsorption. The desorption ratio of Cd(II) from oxidized CBDB was higher than that from unoxidized CBDB in the desorption process using NH 4 NO 3 and EDTA as desorbent. The results presented in this study suggest that KMnO 4 modified CBDB may be used as a safe and high efficient adsorbent in Cd(II) removal from water

Response of cyanobacterial mats to nutrient and salinity changes

Czech Academy of Sciences Publication Activity Database

Rejmánková, E.; Komárková, Jaroslava

2005-01-01

Roč. 83, č. 2 (2005), s. 87-107 ISSN 0304-3770. [INTECOL International Wetlands Conference /7./. Utrecht, 25.07.2004-30.7.2004] Grant - others:NSF(US) 0089211 Institutional research plan: CEZ:AV0Z60170517 Keywords : cyanobacterial mats * Belize * P-N impact Subject RIV: EH - Ecology, Behaviour Impact factor: 1.344, year: 2005

Linking cascading effects of fish predation and zooplankton grazing to reduced cyanobacterial biomass and toxin levels following biomanipulation.

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Mattias K Ekvall

Full Text Available Eutrophication has been one of the largest environmental problems in aquatic ecosystems during the past decades, leading to dense, and often toxic, cyanobacterial blooms. In a way to counteract these problems many lakes have been subject to restoration through biomanipulation. Here we combine 13 years of monitoring data with experimental assessment of grazing efficiency of a naturally occurring zooplankton community and a, from a human perspective, desired community of large Daphnia to assess the effects of an altered trophic cascade associated with biomanipulation. Lake monitoring data show that the relative proportion of Daphnia spp. grazers in June has increased following years of biomanipulation and that this increase coincides with a drop in cyanobacterial biomass and lowered microcystin concentrations compared to before the biomanipulation. In June, the proportion of Daphnia spp. (on a biomass basis went from around 3% in 2005 (the first year of biomanipulation up to around 58% in 2012. During months when the proportion of Daphnia spp. remained unchanged (July and August no effect on lower trophic levels was observed. Our field grazing experiment revealed that Daphnia were more efficient in controlling the standing biomass of cyanobacteria, as grazing by the natural zooplankton community never even compensated for the algal growth during the experiment and sometimes even promoted cyanobacterial growth. Furthermore, although the total cyanobacterial toxin levels remained unaffected by both grazer communities in the experimental study, the Daphnia dominated community promoted the transfer of toxins to the extracellular, dissolved phase, likely through feeding on cyanobacteria. Our results show that biomanipulation by fish removal is a useful tool for lake management, leading to a top-down mediated trophic cascade, through alterations in the grazer community, to reduced cyanobacterial biomass and lowered cyanobacterial toxin levels. This

Practices that Prevent the Formation of Cyanobacterial Blooms in Water Resources and remove Cyanotoxins during Physical Treatment of Drinking Water

Science.gov (United States)

This book chapter presents findings of different studies on the prevention and elimination of cyanobacterial blooms in raw water resources as well as the removal of cyanotoxins during water treatment with physical processes. Initially,treatments that can be applied at the source ...

Accumulation of cyanobacterial toxins in freshwater 'seafood' and its consequences for public health: A review

International Nuclear Information System (INIS)

Ibelings, Bas W.; Chorus, Ingrid

2007-01-01

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in 'seafood' collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and the likelihood of bioaccumulation discussed; (b) we derive cyanotoxin doses likely to occur through seafood consumption and propose guideline values for seafood and compare these to guidelines for drinking water; and (c) we discuss means to assess, control or mitigate the risks of exposure to cyanotoxins through seafood consumption. This is discussed in the context of two specific procedures, the food specific HACCP-approach and the water-specific Water Safety Plan approach by the WHO. Risks of exposure to cyanotoxins in food are sometimes underestimated. Risk assessments should acknowledge this and investigate the partitioning of exposure between drinking-water and food, which may vary depending on local circumstances. - Accumulation of cyanobacterial toxins in freshwater 'seafood'

Impacts of microcystin, a cyanobacterial toxin, on laboratory rodents in vivo

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Andrea Ziková

2008-01-01

Full Text Available Cyanobacterial water blooms became a global problem/issue because beside a dramatic deterioration of water quality parameters they also produce cyanobacterial toxins being harmful for animals and humans. Cyanotoxins especially the most prominent one, microcystin-LR (MC-LR, are of major concern and they have been reported to cause even death of mammals following ingestion or ingurgitation due to hepatotoxic modes of action. The aim of the recent study is to summarize briefly the impacts of microcystin on laboratory rodents, mice and rats, being used as models for other mammals including human beings. Most experimental approaches used intraperitoneal rather than oral and intratracheal application of microcystins, especially MC-LR, being the most efficient way to induce adverse impacts on different target organs. However, no matter how the exposure of rodents was performed, microcystins induced severe harmful impacts on the different target organs, preferentially the liver, for instances hemorrhages and apoptosis in liver, liver tumours, adverse effects on gut, kidney, testis and epididymis including spermatogenesis, on lung, on serum parameters and on progeny. In addition to these histological findings, microcystin was found to affect specifically biochemical parameters of target organs such as enzymes e.g. GST, CAT, GR, GPX, SOD, AST, ALT, γ-GT, protein phosphatases, SDH, SoDH and LDH or stress proteins such as HSP-70 and further parameters such as hepatic sulfhydryl content, GSH depletion, total bilirubin, urea nitrogen, and creatinine. Gene array analyses revealed that microcystin affects genes related to actin organization, cell cycle, apoptosis, cellular redox potential, cell signalling, albumin metabolism, glucose homeostasis pathway and organic anion transport polypeptide system. In combination with a further proteomics approach the proteomic analyses indicate that liver apoptosis induced by microcystin can be induced by two pathways: the

Carotenoids are essential for the assembly of cyanobacterial photosynthetic complexes

Czech Academy of Sciences Publication Activity Database

Tóth, T. N.; Chukhutsina, V.; Knoppová, Jana; Komenda, Josef; Kis, M.; Lenart, Z.; Garab, G.; Kovács, L.; Gombos, Z.; van Amerongen, H.

2015-01-01

Roč. 1847, č. 10 (2015), s. 1153-1165 ISSN 0005-2728 R&D Projects: GA ČR GBP501/12/G055; GA MŠk LO1416 Institutional support: RVO:61388971 Keywords : Carotenoid deficiency * Cyanobacterial photosynthesis * Phycobilisome Subject RIV: CE - Biochemistry Impact factor: 4.864, year: 2015

Conformational heterogeneity of the Pfr chromophore in plant and cyanobacterial phytochromes

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Francisco eVelazquez Escobar

2015-07-01

Full Text Available Phytochromes are biological photoreceptors that can be reversibly photoconverted between a dark and photoactivated state. The underlying reaction sequences are initiated by the photoisomerisation of the tetrapyrrole cofactor, which in plant and cyanobacterial phytochromes are a phytochromobilin (PB and a phycocyanobilin (PCB, respectively. The transition between the two states represents an on/off-switch of the output module activating or deactivating downstream physiological processes. In addition, the photoactivated state, i.e. Pfr in canonical phytochromes, can be thermally reverted to the dark state (Pr. The present study aimed to improve our understanding of the specific reactivity of various PB- and PCB-binding phytochromes in the Pfr state by analyzing the cofactor structure by vibrational spectroscopic techniques. Resonance Raman (RR spectroscopy revealed two Pfr conformers (Pfr-I and Pfr-II forming a temperature-dependent conformational equilibrium. The two sub-states - found in all phytochromes studied, albeit with different relative contributions - differ in structural details of the C-D and A-B methine bridges. In the Pfr-I sub-state the torsion between the rings C and D is larger by ca. 10o compared to Pfr-II. This structural difference is presumably related to different hydrogen bonding interactions of ring D as revealed by time-resolved IR spectroscopic studies of the cyanobacterial phytochrome Cph1. The transitions between the two sub-states are evidently too fast (i.e., nanosecond time scale to be resolved by NMR spectroscopy which could not detect a structural heterogeneity of the chromophore in Pfr. The implications of the present findings for the dark reversion of the Pfr state are discussed.

Three-dimensional structure and cyanobacterial activity within a desert biological soil crust.

Science.gov (United States)

Raanan, Hagai; Felde, Vincent J M N L; Peth, Stephan; Drahorad, Sylvie; Ionescu, Danny; Eshkol, Gil; Treves, Haim; Felix-Henningsen, Peter; Berkowicz, Simon M; Keren, Nir; Horn, Rainer; Hagemann, Martin; Kaplan, Aaron

2016-02-01

Desert biological soil crusts (BSCs) are formed by adhesion of soil particles to polysaccharides excreted by filamentous cyanobacteria, the pioneers and main producers in this habitat. Biological soil crust destruction is a central factor leading to land degradation and desertification. We study the effect of BSC structure on cyanobacterial activity. Micro-scale structural analysis using X-ray microtomography revealed a vesiculated layer 1.5-2.5 mm beneath the surface in close proximity to the cyanobacterial location. Light profiles showed attenuation with depth of 1%-5% of surface light within 1 mm but also revealed the presence of 'light pockets', coinciding with the vesiculated layer, where the irradiance was 10-fold higher than adjacent crust parts at the same depth. Maximal photosynthetic activity, examined by O2 concentration profiles, was observed 1 mm beneath the surface and another peak in association with the 'light pockets'. Thus, photosynthetic activity may not be visible to currently used remote sensing techniques, suggesting that BSCs' contribution to terrestrial productivity is underestimated. Exposure to irradiance higher than 10% full sunlight diminished chlorophyll fluorescence, whereas O2 evolution and CO2 uptake rose, indicating that fluorescence did not reflect cyanobacterial photosynthetic activity. Our data also indicate that although resistant to high illumination, the BSC-inhabiting cyanobacteria function as 'low-light adapted' organisms. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Modification of cyanobacterial bloom-derived biomass using potassium permanganate enhanced the removal of microcystins and adsorption capacity toward cadmium (II)

Energy Technology Data Exchange (ETDEWEB)

Shao, Jihai [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Gu, Ji-Dong [Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use, Hunan Agricultural University, Changsha 410128 (China); Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region (Hong Kong); Peng, Liang; Luo, Si; Luo, Huili [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Yan, Zhiyong, E-mail: zhyyan111@163.com [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Wu, Genyi, E-mail: wugenyi99@163.com [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China)

2014-05-01

Highlights: • Potassium permanganate removed microcystins in the cyanobacterial bloom-derived biomass (CBDB). • Potassium permanganate oxidation caused the transformation of hydroxyl to carboxyl on the CBDB. • Manganese dioxide was formed on the surface of CBDB. • Potassium permanganate oxidation process increased the adsorption capacity of CBDB toward Cd(II). - Abstract: Cyanobacterial biomass shows high adsorption capacity toward heavy metal ions. However, the cyanotoxins in the cyanobacterial biomass inhibit its application in heavy metals removal. In order to safely and effectively remove Cd(II) from water using cyanobacterial bloom-derived biomass (CBDB), KMnO{sub 4} was used to modify CBDB. The results indicated that the microcystins in the CBDB were successfully removed by KMnO{sub 4}. Potassium permanganate oxidation caused the transformation of hydroxyl to carboxyl on the CBDB, and formed manganese dioxide on the surface of CBDB. The oxidized CBDB showed higher adsorption capacity toward Cd(II) than that of unoxidized treatment. The optimal KMnO{sub 4} concentration for increasing the adsorption capacity of CBDB toward Cd(II) was 0.2 g/L. The adsorption isotherm of Cd(II) by oxidized- or unoxidized-CBDB was well fitted by Langmuir model, indicating that the adsorption of Cd(II) by CBDB was monolayer adsorption. The desorption ratio of Cd(II) from oxidized CBDB was higher than that from unoxidized CBDB in the desorption process using NH{sub 4}NO{sub 3} and EDTA as desorbent. The results presented in this study suggest that KMnO{sub 4} modified CBDB may be used as a safe and high efficient adsorbent in Cd(II) removal from water.

Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

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Williams, Wendy; Büdel, Burkhard; Williams, Stephen

2018-04-01

The Boodjamulla National Park research station is situated in the north-western Queensland dry savannah, where the climate is dominated by summer monsoons and virtually dry winters. Under shrub canopies and in between the tussock grasses cyanobacterial crusts almost entirely cover the flood plain soil surfaces. Seasonality drives N fixation, and in the savannah this has a large impact on both plant and soil function. Many cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. We examined cyanobacterial species richness and bioavailable N spanning 7 months of a typical wet season. Over the wet season cyanobacterial richness ranged from 6 to 19 species. N-fixing Scytonema accounted for seasonal averages between 51 and 93 % of the biocrust. Cyanobacterial richness was highly correlated with N fixation and bioavailable N in 0-1 cm. Key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N soil enrichment via cyanobacteria would be ˜ 5.2 kg ha-1 annually which is comparable to global averages. This is a substantial contribution to the nutrient-deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N fixation, bioavailable N and C fixation (Büdel et al., 2018) provide important contributions to multifunctional microprocesses and soil fertility.

An overview of cyanobacterial bloom occurrences and research in Africa over the last decade.

Science.gov (United States)

Ndlela, L L; Oberholster, P J; Van Wyk, J H; Cheng, P H

2016-12-01

Cyanobacterial blooms are a current cause for concern globally, with vital water sources experiencing frequent and increasingly toxic blooms in the past decade. These increases are resultant of both anthropogenic and natural factors, with climate change being the central concern. Of the more affected parts of the world, Africa has been considered particularly vulnerable due to its historical predisposition and lag in social economic development. This review collectively assesses the available information on cyanobacterial blooms in Africa as well as any visible trends associated with reported occurrences over the last decade. Of the 54 countries in Africa, only 21 have notable research information in the area of cyanobacterial blooms within the last decade, although there is substantial reason to attribute these blooms as some of the major water quality threats in Africa collectively. The collected information suggests that civil wars, disease outbreaks and inadequate infrastructure are at the core of Africa's delayed advancement. This is even more so in the area of cyanobacteria related research, with 11 out of 21 countries having recorded toxicity and physicochemical parameters related to cyanobacterial blooms. Compared to the rest of the continent, peripheral countries are at the forefront of research related to cyanobacteria, with countries such as Angola having sufficient rainfall, but poor water quality with limited information on bloom occurrences. An assessment of the reported blooms found nitrogen concentrations to be higher in the water column of more toxic blooms, validating recent global studies and indicating that phosphorous is not the only factor to be monitored in bloom mitigation. Blooms occurred at low TN: TP ratios and at temperatures above 12°C. Nitrogen was linked to toxicity and temperature also had a positive effect on bloom occurrence and toxicity. Microcystis was the most ubiquitous of the cyanobacterial strains reported in Africa and the

The history of cyanobacterial blooms in the Baltic Sea.

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Finni, T; Kononen, K; Olsonen, R; Wallström, K

2001-08-01

Long-term information on possible changes in cyanobacterial blooms in the Baltic Sea, formed mainly by Nodularia spumigena and Aphanizomenon sp., was sought in published records in historical (years 1887-1938) and modern (years 1974-1998) phytoplankton data sets. Old and new sampling methods and fixatives were tested to improve the comparison of data that had been collected and analyzed in different ways. A hundred years ago, plankton was mainly of interest as a source of fish food; eutrophication problems were only locally reported from the coast, mainly in southern haffs and the receiving waters of larger cities. There were few recordings of open-sea blooms before World War II. Abundances of Nodularia spumigena and Aphanizomenon sp. were low in the old material, and 137 summer samples from 1887-1938 showed no peak abundance. High abundances are common in the new material, and the range of the numbers of both taxa has increased markedly relative to the old material. Since the 1960s, cyanobacterial blooms have been common in the open sea in both the Baltic proper and the Gulf of Finland, indicating high availability of nutrients.

Cyanobacterial bloom in the world largest freshwater lake Baikal

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Namsaraev, Zorigto; Melnikova, Anna; Ivanov, Vasiliy; Komova, Anastasia; Teslyuk, Anton

2018-02-01

Lake Baikal is a UNESCO World Heritage Site and holds 20% of the world’s freshwater reserves. On July 26, 2016, a cyanobacterial bloom of a green colour a few kilometers in size with a bad odor was discovered by local people in the Barguzinsky Bay on the eastern shore of Lake Baikal. Our study showed very high concentration of chlorophyll a (41.7 g/m3) in the sample of bloom. We found that the bloom was dominated by a nitrogen-fixing heterocystous cyanobacteria of the genus Dolichospermum. The mass accumulation of cyanobacteria in the lake water with an extremely high chlorophyll a concentration can be explained by a combination of several factors: the discharge of biologicaly-available nutrients, including phosphorus, into the water of Lake Baikal; low wind speed and weak water mixing; buoyant cyanobacterial cells on the lake surface, which drifted towards the eastern coast, where the maximum concentration of chlorophyll a was recorded. In the center of the Barguzinsky Bay and in the open part of Lake Baikal, according to satellite data, the chlorophyll a concentration is several orders of magnitude lower than at the shoreline.

Bioreactor Study Employing Bacteria with Enhanced Activity toward Cyanobacterial Toxins Microcystins

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Dariusz Dziga

2014-08-01

Full Text Available An important aim of white (grey biotechnology is bioremediation, where microbes are employed to remove unwanted chemicals. Microcystins (MCs and other cyanobacterial toxins are not industrial or agricultural pollutants; however, their occurrence as a consequence of human activity and water reservoir eutrophication is regarded as anthropogenic. Microbial degradation of microcystins is suggested as an alternative to chemical and physical methods of their elimination. This paper describes a possible technique of the practical application of the biodegradation process. The idea relies on the utilization of bacteria with a significantly enhanced MC-degradation ability (in comparison with wild strains. The cells of an Escherichia coli laboratory strain expressing microcystinase (MlrA responsible for the detoxification of MCs were immobilized in alginate beads. The degradation potency of the tested bioreactors was monitored by HPLC detection of linear microcystin LR (MC-LR as the MlrA degradation product. An open system based on a column filled with alginate-entrapped cells was shown to operate more efficiently than a closed system (alginate beads shaken in a glass container. The maximal degradation rate calculated per one liter of carrier was 219.9 µg h−1 of degraded MC-LR. A comparison of the efficiency of the described system with other biological and chemo-physical proposals suggests that this new idea presents several advantages and is worth investigating in future studies.

State of knowledge and concerns on cyanobacterial blooms and cyanotoxins.

Science.gov (United States)

Merel, Sylvain; Walker, David; Chicana, Ruth; Snyder, Shane; Baurès, Estelle; Thomas, Olivier

2013-09-01

Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

OpenAIRE

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and li...

Temperature effects explain continental scale distribution of cyanobacterial toxins

OpenAIRE

Mantzouki, Evanthia; Lürling, Miquel; Fastner, Jutta; de Senerpont Domis, Lisette; Wilk-Woźniak, Elżbieta; Koreivienė, Judita; Seelen, Laura; Teurlincx, Sven; Verstijnen, Yvon; Krztoń, Wojciech; Walusiak, Edward; Karosienė, Jūratė; Kasperovičienė, Jūratė; Savadova, Ksenija; Vitonytė, Irma

2018-01-01

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and li...

Cyanobacterial biomass as carbohydrate and nutrient feedstock for bioethanol production by yeast fermentation

DEFF Research Database (Denmark)

Möllers, K Benedikt; Canella, D.; Jørgensen, Henning

2014-01-01

cyanobacterium Synechococcus sp. PCC 7002 was fermented using yeast into bioethanol. Results: The cyanobacterium accumulated a total carbohydrate content of about 60% of cell dry weight when cultivated under nitrate limitation. The cyanobacterial cells were harvested by centrifugation and subjected to enzymatic...... cyanobacteria or microalgae. Importantly, as well as fermentable carbohydrates, the cyanobacterial hydrolysate contained additional nutrients that promoted fermentation. This hydrolysate is therefore a promising substitute for the relatively expensive nutrient additives (such as yeast extract) commonly used...... hydrolysis using lysozyme and two alpha-glucanases. This enzymatic hydrolysate was fermented into ethanol by Saccharomyces cerevisiae without further treatment. All enzyme treatments and fermentations were carried out in the residual growth medium of the cyanobacteria with the only modification being that p...

Effects of two different high-fidelity DNA polymerases on genetic analysis of the cyanobacterial community structure in a subtropical deep freshwater reservoir

DEFF Research Database (Denmark)

Zhen, Zhuo; Liu, Jingwen; Rensing, Christopher Günther T

2017-01-01

and diversity analysis. In this study, two clone libraries were constructed with two different DNA polymerases, Q5 high-fidelity DNA polymerase and exTaq polymerase, to compare the differences in their capability to accurately reflect the cyanobacterial community structure and diversity in a subtropical deep......-fidelity DNA polymerase. It is noteworthy that so far Q5 high-fidelity DNA polymerase was the first time to be employed in the genetic analysis of cyanobacterial community. And it is for the first time that the cyanobacterial community structure in Dongzhen reservoir was analyzed using molecular methods...

Wet season cyanobacterial N enrichment highly correlated with species richness and Nostoc in the northern Australian savannah

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W. Williams

2018-04-01

Full Text Available The Boodjamulla National Park research station is situated in the north-western Queensland dry savannah, where the climate is dominated by summer monsoons and virtually dry winters. Under shrub canopies and in between the tussock grasses cyanobacterial crusts almost entirely cover the flood plain soil surfaces. Seasonality drives N fixation, and in the savannah this has a large impact on both plant and soil function. Many cyanobacteria fix dinitrogen that is liberated into the soil in both inorganic and organic N forms. We examined cyanobacterial species richness and bioavailable N spanning 7 months of a typical wet season. Over the wet season cyanobacterial richness ranged from 6 to 19 species. N-fixing Scytonema accounted for seasonal averages between 51 and 93 % of the biocrust. Cyanobacterial richness was highly correlated with N fixation and bioavailable N in 0–1 cm. Key N-fixing species such as Nostoc, Symploca and Gloeocapsa significantly enriched soil N although Nostoc was the most influential. Total seasonal N fixation by cyanobacteria demonstrated the variability in productivity according to the number of wet days as well as the follow-on days where the soil retained adequate moisture. Based on total active days per month we estimated that N soil enrichment via cyanobacteria would be  ∼  5.2 kg ha−1 annually which is comparable to global averages. This is a substantial contribution to the nutrient-deficient savannah soils that are almost entirely reliant on the wet season for microbial turnover of organic matter. Such well-defined seasonal trends and synchronisation in cyanobacterial species richness, N fixation, bioavailable N and C fixation (Büdel et al., 2018 provide important contributions to multifunctional microprocesses and soil fertility.

Development of immobilized cyanobacterial amendments for reclamation of microbiotic soil crusts

Czech Academy of Sciences Publication Activity Database

Kubečková, Klára; Johansen, J. R.; Warren, S. D.; Sparks, R.

2003-01-01

Roč. 148, č. 109 (2003), s. 341-362 ISSN 0342-1120. [Symposium of the International Association for Cyanophyte Research/15./. Barcelona, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR KSK6005114 Keywords : cyanobacteria * cyanobacterial amendments * desert soil Subject RIV: EF - Botanics

Characterization of the cyanobacterial biocenosis of a freshwater reservoir in Italy

Czech Academy of Sciences Publication Activity Database

Mugnai, M. A.; Turicchia, S.; Margheri, M. C.; Sili, C.; Gugger, M.; Tedioli, G.; Komárek, Jiří; Ventura, S.

2003-01-01

Roč. 148, č. 109 (2003), s. 403-419 ISSN 0342-1120. [Symposium of the International Association for Cyanophyte Research /15./. Barcelona, 03.09.2001-07.09.2001] R&D Projects: GA AV ČR KSK6005114 Keywords : freshwater reservoir * cyanobacterial diversity * morphology Subject RIV: EF - Botanics

Estimates of global cyanobacterial biomass and its distribution

Science.gov (United States)

Garcia-Pichel, Ferran; Belnap, Jayne; Neuer, Susanne; Schanz, Ferdinand

2003-01-01

We estimated global cyanobacterial biomass in the main reservoirs of cyanobacteria on Earth: marine and freshwater plankton, arid land soil crusts, and endoliths. Estimates were based on typical population density values as measured during our research, or as obtained from literature surveys, which were then coupled with data on global geographical area coverage. Among the marine plankton, the global biomass of Prochlorococcus reaches 120 × 1012 grams of carbon (g C), and that of Synechoccus some 43 × 1012 g C. This makes Prochlorococcus and Synechococcus, in that order, the most abundant cyanobacteria on Earth. Tropical marine blooms of Trichodesmium account for an additional 10 × 1012 g C worldwide. In terrestrial environments, the mass of cyanobacteria in arid land soil crusts is estimated to reach 54 × 1012 g C and that of arid land endolithic communities an additional 14 × 1012 g C. The global biomass of planktic cyanobacteria in lakes is estimated to be around 3 × 1012 g C. Our conservative estimates, which did not include some potentially significant biomass reservoirs such as polar and subarctic areas, topsoils in subhumid climates, and shallow marine and freshwater benthos, indicate that the total global cyanobacterial biomass is in the order of 3 × 1014 g C, surpassing a thousand million metric tons (1015 g) of wet biomass.

In situ determination of the effects of lead and copper on cyanobacterial populations in microcosms.

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Mireia Burnat

Full Text Available BACKGROUND: Biomass has been studied as biomarker to evaluate the effect of heavy metals on microbial communities. Nevertheless, the most important methodological problem when working with natural and artificial microbial mats is the difficulty to evaluate changes produced on microorganism populations that are found in thicknesses of just a few mm depth. METHODOLOGY/PRINCIPAL FINDINGS: Here, we applied for first time a recently published new method based on confocal laser scanning microscopy and image-program analysis to determine in situ the effect of Pb and Cu stress in cyanobacterial populations. CONCLUSIONS/SIGNIFICANCE: The results showed that both in the microcosm polluted by Cu and by Pb, a drastic reduction in total biomass for cyanobacterial and Microcoleus sp. (the dominant filamentous cyanobacterium in microbial mats was detected within a week. According to the data presented in this report, this biomass inspection has a main advantage: besides total biomass, diversity, individual biomass of each population and their position can be analysed at microscale level. CLSM-IA could be a good method for analyzing changes in microbial biomass as a response to the addition of heavy metals and also to other kind of pollutants.

In situ determination of the effects of lead and copper on cyanobacterial populations in microcosms.

Science.gov (United States)

Burnat, Mireia; Diestra, Elia; Esteve, Isabel; Solé, Antonio

2009-07-10

Biomass has been studied as biomarker to evaluate the effect of heavy metals on microbial communities. Nevertheless, the most important methodological problem when working with natural and artificial microbial mats is the difficulty to evaluate changes produced on microorganism populations that are found in thicknesses of just a few mm depth. Here, we applied for first time a recently published new method based on confocal laser scanning microscopy and image-program analysis to determine in situ the effect of Pb and Cu stress in cyanobacterial populations. The results showed that both in the microcosm polluted by Cu and by Pb, a drastic reduction in total biomass for cyanobacterial and Microcoleus sp. (the dominant filamentous cyanobacterium in microbial mats) was detected within a week. According to the data presented in this report, this biomass inspection has a main advantage: besides total biomass, diversity, individual biomass of each population and their position can be analysed at microscale level. CLSM-IA could be a good method for analyzing changes in microbial biomass as a response to the addition of heavy metals and also to other kind of pollutants.

RNA-seq based identification and mutant validation of gene targets related to ethanol resistance in cyanobacterial Synechocystis sp. PCC 6803

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Wang Jiangxin

2012-12-01

Full Text Available Abstract Background Fermentation production of biofuel ethanol consumes agricultural crops, which will compete directly with the food supply. As an alternative, photosynthetic cyanobacteria have been proposed as microbial factories to produce ethanol directly from solar energy and CO2. However, the ethanol productivity from photoautotrophic cyanobacteria is still very low, mostly due to the low tolerance of cyanobacterial systems to ethanol stress. Results To build a foundation necessary to engineer robust ethanol-producing cyanobacterial hosts, in this study we applied a quantitative transcriptomics approach with a next-generation sequencing technology, combined with quantitative reverse-transcript PCR (RT-PCR analysis, to reveal the global metabolic responses to ethanol in model cyanobacterial Synechocystis sp. PCC 6803. The results showed that ethanol exposure induced genes involved in common stress responses, transporting and cell envelope modification. In addition, the cells can also utilize enhanced polyhydroxyalkanoates (PHA accumulation and glyoxalase detoxication pathway as means against ethanol stress. The up-regulation of photosynthesis by ethanol was also further confirmed at transcriptional level. Finally, we used gene knockout strains to validate the potential target genes related to ethanol tolerance. Conclusion RNA-Seq based global transcriptomic analysis provided a comprehensive view of cellular response to ethanol exposure. The analysis provided a list of gene targets for engineering ethanol tolerance in cyanobacterium Synechocystis.

Cyanobacterial pigments as natural anti-hyperglycemic agents: An in vitro study

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Tonmoy Ghosh

2016-08-01

Full Text Available Traditional medicines for controlling postprandial hyperglycemia includes herbs and plant extracts as well as synthetic drugs like acarbose. Synthetic drug molecules frequently have side effects such as flatulence and diarrhea. Cyanobacterial pigments have excellent anti-oxidant and free radical scavenging properties. Thus, α-amylase and α-glucosidase inhibiting activities of purified pigments and crude extracts from three cyanobacterial species, Lyngbya, Microcoleus and Synechocystis sp., were investigated. Lyngbya extract had the highest total anti-oxidant activity (TAC before digestion (48.26 ± 0.04 µg AAE ml-1 while purified lycopene had the highest TAC after digestion (154.16 ± 0.96 µg AAE ml-1. The Microcoleus extract had the highest ABTS scavenging activity before digestion (98.23 ± 0.25 % while purified C-phycocyanin (C-PC had the highest ABTS scavenging after digestion (99.69 ±0.04 %. None of the digested or undigested extracts performed better than acarbose in inhibiting α-amylase but the digested Microcoleus extract was able to inhibit its activity by ~35 %. The purified pigments gave inhibitory activities ranging from ~ 8 – 16 %. The Lyngbya extract had the highest inhibitory activity against α-glucosidase both before and after digestion (62.22 ± 0.02 and 97.82 ± 0.03 % respectively. Purified C-phycoerythrin (C-PE, C-PC, lycopene and myxoxanthophyll could inhibit α-glucosidase in a range of ~83 – 96 %. Considering the potent inhibitory activities of purified pigments against both α-amylase and α-glucosidase, cyanobacterial pigments could be used as food additives for their dual advantage of anti-oxidant and anti-hyperglycemic activities.

Community phylogenetic analysis of moderately thermophilic cyanobacterial mats from China, the Philippines and Thailand.

Science.gov (United States)

Hongmei, Jing; Aitchison, Jonathan C; Lacap, Donnabella C; Peerapornpisal, Yuwadee; Sompong, Udomluk; Pointing, Stephen B

2005-08-01

Most community molecular studies of thermophilic cyanobacterial mats to date have focused on Synechococcus occurring at temperatures of approximately 50-65 degrees C. These reveal that molecular diversity exceeds that indicated by morphology, and that phylogeographic lineages exist. The moderately thermophilic and generally filamentous cyanobacterial mat communities occurring at lower temperatures have not previously been investigated at the community molecular level. Here we report community diversity in mats of 42-53 degrees C recovered from previously unstudied geothermal locations. Separation of 16S rRNA gene-defined genotypes from community DNA was achieved by DGGE. Genotypic diversity was greater than morphotype diversity in all mats sampled, although genotypes generally corresponded to observed morphotypes. Thirty-six sequences were recovered from DGGE bands. Phylogenetic analyses revealed these to form novel thermophilic lineages distinct from their mesophilic counterparts, within Calothrix, Cyanothece, Fischerella, Phormidium, Pleurocapsa, Oscillatoria and Synechococcus. Where filamentous cyanobacterial sequences belonging to the same genus were recovered from the same site, these were generally closely affiliated. Location-specific sequences were observed for some genotypes recovered from geochemically similar yet spatially separated sites, thus providing evidence for phylogeographic lineages that evolve in isolation. Other genotypes were more closely affiliated to geographically remote counterparts from similar habitats suggesting that adaptation to certain niches is also important.

Accumulation of cyanobacterial toxins in freshwater 'seafood' and its consequences for public health: A review

Energy Technology Data Exchange (ETDEWEB)

Ibelings, Bas W. [Eawag, Swiss Federal Institute of Aquatic Sciences and Technology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum (Switzerland); Netherlands Institute of Ecology, Centre for Limnology, Rijksstraatweg 6, 3631 AC, Nieuwersluis (Netherlands)], E-mail: bas.ibelings@eawag.ch; Chorus, Ingrid [German Federal Environment Agency, Corrensplatz 1, 14195 Berlin (Germany)], E-mail: ingrid.chorus@uba.de

2007-11-15

This review summarizes and discusses the current understanding of human exposure to cyanobacterial toxins in 'seafood' collected from freshwater and coastal areas. The review consists of three parts: (a) the existing literature on concentrations of cyanobacterial toxins in seafood is reviewed, and the likelihood of bioaccumulation discussed; (b) we derive cyanotoxin doses likely to occur through seafood consumption and propose guideline values for seafood and compare these to guidelines for drinking water; and (c) we discuss means to assess, control or mitigate the risks of exposure to cyanotoxins through seafood consumption. This is discussed in the context of two specific procedures, the food specific HACCP-approach and the water-specific Water Safety Plan approach by the WHO. Risks of exposure to cyanotoxins in food are sometimes underestimated. Risk assessments should acknowledge this and investigate the partitioning of exposure between drinking-water and food, which may vary depending on local circumstances. - Accumulation of cyanobacterial toxins in freshwater 'seafood'.

Controlling harmful cyanobacterial blooms in a world experiencing anthropogenic and climatic-induced change

International Nuclear Information System (INIS)

Paerl, Hans W.; Hall, Nathan S.; Calandrino, Elizabeth S.

2011-01-01

Harmful (toxic, food web altering, hypoxia generating) cyanobacterial algal blooms (CyanoHABs) are proliferating world-wide due to anthropogenic nutrient enrichment, and they represent a serious threat to the use and sustainability of our freshwater resources. Traditionally, phosphorus (P) input reductions have been prescribed to control CyanoHABs, because P limitation is widespread and some CyanoHABs can fix atmospheric nitrogen (N 2 ) to satisfy their nitrogen (N) requirements. However, eutrophying systems are increasingly plagued with non N 2 fixing CyanoHABs that are N and P co-limited or even N limited. In many of these systems N loads are increasing faster than P loads. Therefore N and P input constraints are likely needed for long-term CyanoHAB control in such systems. Climatic changes, specifically warming, increased vertical stratification, salinization, and intensification of storms and droughts play additional, interactive roles in modulating CyanoHAB frequency, intensity, geographic distribution and duration. In addition to having to consider reductions in N and P inputs, water quality managers are in dire need of effective tools to break the synergy between nutrient loading and hydrologic regimes made more favorable for CyanoHABs by climate change. The more promising of these tools make affected waters less hospitable for CyanoHABs by 1) altering the hydrology to enhance vertical mixing and/or flushing and 2) decreasing nutrient fluxes from organic rich sediments by physically removing the sediments or capping sediments with clay. Effective future CyanoHAB management approaches must incorporate both N and P loading dynamics within the context of altered thermal and hydrologic regimes associated with climate change. - Research Highlights: → Toxic cyanobacterial blooms (CyanoHABs) increasingly threaten global water supplies. → Human (nutrient) and climate (hydrology, temperature) changes synergistically promote CyanoHABs. → CyanoHAB control

Predicting cyanobacterial abundance, microcystin, and geosmin in a eutrophic drinking-water reservoir using a 14-year dataset

Science.gov (United States)

Harris, Ted D.; Graham, Jennifer L.

2017-01-01

Cyanobacterial blooms degrade water quality in drinking water supply reservoirs by producing toxic and taste-and-odor causing secondary metabolites, which ultimately cause public health concerns and lead to increased treatment costs for water utilities. There have been numerous attempts to create models that predict cyanobacteria and their secondary metabolites, most using linear models; however, linear models are limited by assumptions about the data and have had limited success as predictive tools. Thus, lake and reservoir managers need improved modeling techniques that can accurately predict large bloom events that have the highest impact on recreational activities and drinking-water treatment processes. In this study, we compared 12 unique linear and nonlinear regression modeling techniques to predict cyanobacterial abundance and the cyanobacterial secondary metabolites microcystin and geosmin using 14 years of physiochemical water quality data collected from Cheney Reservoir, Kansas. Support vector machine (SVM), random forest (RF), boosted tree (BT), and Cubist modeling techniques were the most predictive of the compared modeling approaches. SVM, RF, and BT modeling techniques were able to successfully predict cyanobacterial abundance, microcystin, and geosmin concentrations <60,000 cells/mL, 2.5 µg/L, and 20 ng/L, respectively. Only Cubist modeling predicted maxima concentrations of cyanobacteria and geosmin; no modeling technique was able to predict maxima microcystin concentrations. Because maxima concentrations are a primary concern for lake and reservoir managers, Cubist modeling may help predict the largest and most noxious concentrations of cyanobacteria and their secondary metabolites.

Organic matter degradation drives benthic cyanobacterial mat abundance on caribbean coral reefs

NARCIS (Netherlands)

Brocke, Hannah J.; Polerecky, Lubos; De Beer, Dirk; Weber, Miriam; Claudet, Joachim; Nugues, Maggy M.

2015-01-01

Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised

Toxic Cyanobacterial Bloom Triggers in Missisquoi Bay, Lake Champlain, as Determined by Next-Generation Sequencing and Quantitative PCR

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Nathalie Fortin

2015-05-01

Full Text Available Missisquoi Bay (MB is a temperate eutrophic freshwater lake that frequently experiences toxic Microcystis-dominated cyanobacterial blooms. Non-point sources are responsible for the high concentrations of phosphorus and nitrogen in the bay. This study combined data from environmental parameters, E. coli counts, high-throughput sequencing of 16S rRNA gene amplicons, quantitative PCR (16S rRNA and mcyD genes and toxin analyses to identify the main bloom-promoting factors. In 2009, nutrient concentrations correlated with E. coli counts, abundance of total cyanobacterial cells, Microcystis 16S rRNA and mcyD genes and intracellular microcystin. Total and dissolved phosphorus also correlated significantly with rainfall. The major cyanobacterial taxa were members of the orders Chroococcales and Nostocales. The genus Microcystis was the main mcyD-carrier and main microcystin producer. Our results suggested that increasing nutrient concentrations and total nitrogen:total phosphorus (TN:TP ratios approaching 11:1, coupled with an increase in temperature, promoted Microcystis-dominated toxic blooms. Although the importance of nutrient ratios and absolute concentrations on cyanobacterial and Microcystis dynamics have been documented in other laboratories, an optimum TN:TP ratio for Microcystis dominance has not been previously observed in situ. This observation provides further support that nutrient ratios are an important determinant of species composition in natural phytoplankton assemblages.

Time-dependent alterations in growth, photosynthetic pigments and enzymatic defense systems of submerged Ceratophyllum demersum during exposure to the cyanobacterial neurotoxin anatoxin-a

Energy Technology Data Exchange (ETDEWEB)

Ha, Mi-Hee; Pflugmacher, Stephan, E-mail: stephan.pflugmacher@tu-berlin.de

2013-08-15

Highlights: •We examined time-dependent metabolic changes in C. demersum exposed to anatoxin-a. •Biotransformation and antioxidative defense mechanisms responded positively to anatoxin-a. •Decline in chlorophylls contents was detected in company with irreversible plant growth inhibition during exposure to anatoxin-a. •Anatoxin-a exhibits phytotoxic allelopathy by provoking oxidative stress. •Macrophytes may have interactions with anatoxin-a in aquatic environments. -- Abstract: Recently, aquatic macrophytes have been considered as promising tools for eco-friendly water management with a low running cost. However, only little information is available thus far regarding the metabolic capacity of macrophytes for coping with cyanobacterial toxins (cyanotoxins) in the aquatic environment. Cyanotoxins have become emerging contaminants of great concern due to the high proliferation of cyanobacteria (cyanobacterial bloom) accelerated by eutrophication and climate change. Anatoxin-a, one of the common and major cyanotoxins, is suggested as a high priority water pollutant for regulatory consideration owing to its notoriously rapid mode of action as a neurotoxin. In this study, the time-course metabolic regulation of the submerged macrophyte Ceratophyllum demersum (C. demersum) was investigated during exposure to anatoxin-a at an environmentally relevant concentration (15 μg/L). Biotransformation and antioxidative systems in C. demersum responded positively to anatoxin-a through the promoted synthesis of most of the involved enzymes within 8 h. Maximum enzyme activities were exhibited after 24 or 48 h of exposure to anatoxin-a. However, an apparent decline in enzyme activities was also observed at longer exposure duration (168 and 336 h) in company with high steady-state levels of cell internal H{sub 2}O{sub 2}, which showed its highest level after 48 h. Meanwhile, irreversible inhibitory influence on chlorophyll content (vitality) was noticed, whereas the ratio of

Time-dependent alterations in growth, photosynthetic pigments and enzymatic defense systems of submerged Ceratophyllum demersum during exposure to the cyanobacterial neurotoxin anatoxin-a

International Nuclear Information System (INIS)

Ha, Mi-Hee; Pflugmacher, Stephan

2013-01-01

Highlights: •We examined time-dependent metabolic changes in C. demersum exposed to anatoxin-a. •Biotransformation and antioxidative defense mechanisms responded positively to anatoxin-a. •Decline in chlorophylls contents was detected in company with irreversible plant growth inhibition during exposure to anatoxin-a. •Anatoxin-a exhibits phytotoxic allelopathy by provoking oxidative stress. •Macrophytes may have interactions with anatoxin-a in aquatic environments. -- Abstract: Recently, aquatic macrophytes have been considered as promising tools for eco-friendly water management with a low running cost. However, only little information is available thus far regarding the metabolic capacity of macrophytes for coping with cyanobacterial toxins (cyanotoxins) in the aquatic environment. Cyanotoxins have become emerging contaminants of great concern due to the high proliferation of cyanobacteria (cyanobacterial bloom) accelerated by eutrophication and climate change. Anatoxin-a, one of the common and major cyanotoxins, is suggested as a high priority water pollutant for regulatory consideration owing to its notoriously rapid mode of action as a neurotoxin. In this study, the time-course metabolic regulation of the submerged macrophyte Ceratophyllum demersum (C. demersum) was investigated during exposure to anatoxin-a at an environmentally relevant concentration (15 μg/L). Biotransformation and antioxidative systems in C. demersum responded positively to anatoxin-a through the promoted synthesis of most of the involved enzymes within 8 h. Maximum enzyme activities were exhibited after 24 or 48 h of exposure to anatoxin-a. However, an apparent decline in enzyme activities was also observed at longer exposure duration (168 and 336 h) in company with high steady-state levels of cell internal H 2 O 2 , which showed its highest level after 48 h. Meanwhile, irreversible inhibitory influence on chlorophyll content (vitality) was noticed, whereas the ratio of

Correlations between cyanobacterial density and bacterial transformation to the viable but nonculturable (VBNC) state in four freshwater water bodies.

Science.gov (United States)

Chen, Huirong; Shen, Ju; Pan, Gaoshan; Liu, Jing; Li, Jiancheng; Hu, Zhangli

2015-10-01

Nutrient concentrations, phytoplankton density and community composition, and the viable but nonculturable (VBNC) state of heterotrophic bacteria were investigated in three connected reservoirs and a small isolated lake in South China to study the relationship between biotic and abiotic factors and the VBNC state in bacteria. Nutrient concentrations in the reservoirs increased in the direction of water flow, whereas Wenshan Lake was more eutrophic. Cyanobacterial blooms occurred in all four water bodies, with differing seasonal trends and dominant species. In Xili and Tiegang Reservoirs, the VBNC ratio (percent of VBNC state bacteria over total viable bacteria) was high for most of the year and negatively correlated with cyanobacterial density. Laboratory co-culture experiments were performed with four heterotrophic bacterial species isolated from Wenshan Lake (Escherichia coli, Klebsiella peneumoniae, Bacillus megaterium and Bacillus cereus) and the dominant cyanobacterial species (Microcystis aeruginosa). For the first three bacterial species, the presence of M. aeruginosa induced the VBNC state and the VBNC ratio was positively correlated with M. aeruginosa density. However, B. cereus inhibited M. aeruginosa growth. These results demonstrate that cyanobacteria could potentially regulate the transformation to the VBNC state of waterborne bacteria, and suggest a role for bacteria in cyanobacterial bloom initiation and termination.

Electrochemical Detection of Circadian Redox Rhythm in Cyanobacterial Cells via Extracellular Electron Transfer.

Science.gov (United States)

Nishio, Koichi; Pornpitra, Tunanunkul; Izawa, Seiichiro; Nishiwaki-Ohkawa, Taeko; Kato, Souichiro; Hashimoto, Kazuhito; Nakanishi, Shuji

2015-06-01

Recent research on cellular circadian rhythms suggests that the coupling of transcription-translation feedback loops and intracellular redox oscillations is essential for robust circadian timekeeping. For clarification of the molecular mechanism underlying the circadian rhythm, methods that allow for the dynamic and simultaneous detection of transcription/translation and redox oscillations in living cells are needed. Herein, we report that the cyanobacterial circadian redox rhythm can be electrochemically detected based on extracellular electron transfer (EET), a process in which intracellular electrons are exchanged with an extracellular electrode. As the EET-based method is non-destructive, concurrent detection with transcription/translation rhythm using bioluminescent reporter strains becomes possible. An EET pathway that electrochemically connected the intracellular region of cyanobacterial cells with an extracellular electrode was constructed via a newly synthesized electron mediator with cell membrane permeability. In the presence of the mediator, the open circuit potential of the culture medium exhibited temperature-compensated rhythm with approximately 24 h periodicity. Importantly, such circadian rhythm of the open circuit potential was not observed in the absence of the electron mediator, indicating that the EET process conveys the dynamic information regarding the intracellular redox state to the extracellular electrode. These findings represent the first direct demonstration of the intracellular circadian redox rhythm of cyanobacterial cells. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cyanobacterial Neurotoxin β-N-Methylamino-L-alanine (BMAA in Shark Fins

Directory of Open Access Journals (Sweden)

John Pablo

2012-02-01

Full Text Available Sharks are among the most threatened groups of marine species. Populations are declining globally to support the growing demand for shark fin soup. Sharks are known to bioaccumulate toxins that may pose health risks to consumers of shark products. The feeding habits of sharks are varied, including fish, mammals, crustaceans and plankton. The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA has been detected in species of free-living marine cyanobacteria and may bioaccumulate in the marine food web. In this study, we sampled fin clips from seven different species of sharks in South Florida to survey the occurrence of BMAA using HPLC-FD and Triple Quadrupole LC/MS/MS methods. BMAA was detected in the fins of all species examined with concentrations ranging from 144 to 1836 ng/mg wet weight. Since BMAA has been linked to neurodegenerative diseases, these results may have important relevance to human health. We suggest that consumption of shark fins may increase the risk for human exposure to the cyanobacterial neurotoxin BMAA.

THE TRPV1 RECEPTOR: THE INTERAGENCY, INTERNATION SYMPOSIUM ON CYANOBACTERIAL HARMFUL ALGAL BLOOMS.

Science.gov (United States)

Background and Significance Evidence indicates that the frequency of occurrence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial and temporal extent in the US and worldwide. Cyanotoxins are among the most potent toxins known, causing death through ...

The cyanobacterial bicarbonate transporter BicA: its physiological role and the implications of structural similarities with human SLC26 transporters.

Science.gov (United States)

Price, G Dean; Howitt, Susan M

2011-04-01

The cyanobacterial Na+-dependent HCO3- transporter BicA is a member of the ubiquitous and important SulP/SLC26 family of anion transporters found in eukaryotes and prokaryotes. BicA is an important component of the cyanobacterial CO2 concentrating mechanism, an adaptation that contributes to cyanobacteria being able to achieve an estimated 25% of global primary productivity, largely in the oceans. The human SLC26 members are involved in a range of key cellular functions involving a diverse range of anion transport activities including Cl-/HCO3-, I-/HCO3-, and SO42-/HCO3- exchange; mutations in SLC26 members are known to be associated with debilitating diseases such as Pendred syndrome, chondrodysplasias, and congenital chloride diarrhoea. We have recently experimentally determined the membrane topology of BicA using the phoA-lacZ reporter system and here consider some of the extrapolated implications for topology of the human SLC26 family and the Sultr plant sulphate transporters.

Emerging health issues of cyanobacterial blooms

Directory of Open Access Journals (Sweden)

Maura Manganelli

2012-12-01

Full Text Available This paper describes emerging issue related to cyanobacterial dynamics and toxicity and human health risks. Data show an increasing cyanobacteria expansion and dominance in many environments. However there are still few information on the toxic species fitness, or on the effects of specific drivers on toxin production. Open research fields are related to new exposure scenario (cyanotoxins in water used for haemodialysis and in food supplements; to new patterns of co-exposure between cyanotoxins and algal toxins and/or anthropogenic chemicals; to dynamics affecting toxicity and production of different cyanotoxin variants under environmental stress; to the accumulation of cyanotoxins in the food web. In addition, many data gaps exist in the characterization of the toxicological profiles, especially about long term effects.

Frequency of inhibitors of daphnid trypsin in the widely distributed cyanobacterial genus Planktothrix

DEFF Research Database (Denmark)

Rohrlack, T.; Christoffersen, K.; Friberg-Jensen, U.

2005-01-01

on the frequency of such compounds in the widely distributed cyanobacterial genus Planktothrix. Of the 89 Planktothrix strains analysed, about 70% produced inhibitors of daphnid trypsin. The strains tested positive represented three common Planktothrix species and were isolated from diverse localities...

Risk to human health associated with the environmental occurrence of cyanobacterial neurotoxic alkaloids anatoxins and saxitoxins.

Science.gov (United States)

Testai, Emanuela; Scardala, Simona; Vichi, Susanna; Buratti, Franca M; Funari, Enzo

2016-01-01

Cyanobacteria are ubiquitous photosynthetic micro-organisms forming blooms and scums in surface water; among them some species can produce cyanotoxins giving rise to some concern for human health and animal life. To date, more than 65 cyanobacterial neurotoxins have been described, of which the most studied are the groups of anatoxins and saxitoxins (STXs), comprising many different variants. In freshwaters, the hepatotoxic microcystins represent the most frequently detected cyanotoxin: on this basis, it could appear that neurotoxins are less relevant, but the low frequency of detection may partially reflect an a priori choice of target analytes, the low method sensitivity and the lack of certified standards. Cyanobacterial neurotoxins target cholinergic synapses or voltage-gated ion channels, blocking skeletal and respiratory muscles, thus leading to death by respiratory failure. This review reports and analyzes the available literature data on environmental occurrence of cyanobacterial neurotoxic alkaloids, namely anatoxins and STXs, their biosynthesis, toxicology and epidemiology, derivation of guidance values and action limits. These data are used as the basis to assess the risk posed to human health, identify critical exposure scenarios and highlight the major data gaps and research needs.

Quantitative iTRAQ LC-MS/MS proteomics reveals metabolic responses to biofuel ethanol in cyanobacterial Synechocystis sp. PCC 6803.

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Qiao, Jianjun; Wang, Jiangxin; Chen, Lei; Tian, Xiaoxu; Huang, Siqiang; Ren, Xiaoyue; Zhang, Weiwen

2012-11-02

Recent progress in metabolic engineering has led to autotrophic production of ethanol in various cyanobacterial hosts. However, cyanobacteria are known to be sensitive to ethanol, which restricts further efforts to increase ethanol production levels in these renewable host systems. To understand the mechanisms of ethanol tolerance so that engineering more robust cyanobacterial hosts can be possible, in this study, the responses of model cyanobacterial Synechocystis sp. PCC 6803 to ethanol were determined using a quantitative proteomics approach with iTRAQ LC-MS/MS technologies. The resulting high-quality proteomic data set consisted of 24,887 unique peptides corresponding to 1509 identified proteins, a coverage of approximately 42% of the predicted proteins in the Synechocystis genome. Using a cutoff of 1.5-fold change and a p-value less than 0.05, 135 and 293 unique proteins with differential abundance levels were identified between control and ethanol-treated samples at 24 and 48 h, respectively. Functional analysis showed that the Synechocystis cells employed a combination of induced common stress response, modifications of cell membrane and envelope, and induction of multiple transporters and cell mobility-related proteins as protection mechanisms against ethanol toxicity. Interestingly, our proteomic analysis revealed that proteins related to multiple aspects of photosynthesis were up-regulated in the ethanol-treated Synechocystis cells, consistent with increased chlorophyll a concentration in the cells upon ethanol exposure. The study provided the first comprehensive view of the complicated molecular mechanisms against ethanol stress and also provided a list of potential gene targets for further engineering ethanol tolerance in Synechocystis PCC 6803.

Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

Energy Technology Data Exchange (ETDEWEB)

Stuart, Rhona K.; Mayali, Xavier; Boaro, Amy A.; Zemla, Adam; Everroad, R. Craig; Nilson, Daniel; Weber, Peter K.; Lipton, Mary; Bebout, Brad M.; Pett-Ridge, Jennifer; Thelen, Michael P.

2016-06-28

Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption. Cyanobacteria in phototrophic biofilms can reuse extracellular organic carbon, but the metabolic drivers of extracellular processes are surprisingly complex. We investigated the metabolic foundations of organic matter reuse by comparing exoproteome composition and incorporation of¹³C-labeled and¹⁵N-labeled cyanobacterial extracellular organic matter (EOM) in a unicyanobacterial biofilm incubated using different light regimes. In the light and the dark, cyanobacterial direct organic C assimilation accounted for 32% and 43%, respectively, of all organic C assimilation in the community. Under photosynthesis conditions, we measured increased excretion of extracellular polymeric substances (EPS) and proteins involved in micronutrient transport, suggesting that requirements for micronutrients may drive EOM assimilation during daylight hours. This interpretation was supported by photosynthesis inhibition experiments, in which cyanobacteria incorporated N-rich EOM-derived material. In contrast, under dark, C-starved conditions, cyanobacteria incorporated C-rich EOM-derived organic matter, decreased excretion of EPS, and showed an increased abundance of degradative exoproteins, demonstrating the use of the extracellular domain for C storage. Sequence-structure modeling of one of these exoproteins predicted a specific hydrolytic activity that was subsequently detected, confirming increased EOM degradation in the dark. Associated heterotrophic bacteria increased in abundance and upregulated transport proteins under dark relative to light conditions. Taken together, our results indicate that biofilm cyanobacteria are successful competitors for organic C and N and that cyanobacterial nutrient and energy requirements control the use of EOM.

Final Technical Report - Use of Systems Biology Approaches to Develop Advanced Biofuel-Synthesizing Cyanobacterial Strains

Energy Technology Data Exchange (ETDEWEB)

Pakrasi, Himadri [Washington Univ., St. Louis, MO (United States)

2016-09-01

The overall objective of this project was to use a systems biology approach to evaluate the potentials of a number of cyanobacterial strains for photobiological production of advanced biofuels and/or their chemical precursors. Cyanobacteria are oxygen evolving photosynthetic prokaryotes. Among them, certain unicellular species such as Cyanothece can also fix N₂, a process that is exquisitely sensitive to oxygen. To accommodate such incompatible processes in a single cell, Cyanothece produces oxygen during the day, and creates an O₂-limited intracellular environment during the night to perform O₂-sensitive processes such as N₂-fixation. Thus, Cyanothece cells are natural bioreactors for the storage of captured solar energy with subsequent utilization at a different time during a diurnal cycle. Our studies include the identification of a novel, fast-growing, mixotrophic, transformable cyanobacterium. This strain has been sequenced and will be made available to the community. In addition, we have developed genome-scale models for a family of cyanobacteria to assess their metabolic repertoire. Furthermore, we developed a method for rapid construction of metabolic models using multiple annotation sources and a metabolic model of a related organism. This method will allow rapid annotation and screening of potential phenotypes based on the newly available genome sequences of many organisms.

State of knowledge and concerns on cyanobacterial blooms and cyanotoxins.

OpenAIRE

Merel , Sylvain; Walker , David; Chicana , Ruth; Snyder , Shane; Baurès , Estelle; Thomas , Olivier

2013-01-01

International audience; Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surf...

The effect of environmental parameters and cyanobacterial blooms on phytoplankton dynamics of a Portuguese temperate lake

DEFF Research Database (Denmark)

De Figueiredo, Daniela R.; P. S. Reboleira, Ana Sofia; Antunes, Sara C.

2006-01-01

The increasing occurrence of cyanobacterial blooms in freshwaters is of great concern due to the ability of many cyanobacteria to produce cyanotoxins. In the present work, the eutrophied Vela Lake (Central Portugal), used for recreational purposes and as a water source for agriculture, was monito...... for the phytoplanktonic assemblage during the study period was increased in about 7% achieving a total of 61.0%, indicating a correlation that may be due to the known competitive advantage and/or allelopathy of the bloom-forming cyanobacteria towards microalgae....

Two Marine Cyanobacterial Aplysiatoxin Polyketides, Neo-debromoaplysiatoxin A and B, with K+ Channel Inhibition Activity.

Science.gov (United States)

Han, Bing-Nan; Liang, Ting-Ting; Keen, Lawrence Jordan; Fan, Ting-Ting; Zhang, Xiao-Dan; Xu, Lin; Zhao, Qi; Wang, Shu-Ping; Lin, Hou-Wen

2018-02-02

The isolation and structure elucidation of two cyanobacterial debromoaplysiatoxin (DAT) analogues, neo-debromoaplysiatoxin A (1) and neo-debromoaplysiatoxin B (2), were reported and found to possess 6/10/6 and 6/6/6 fused-ring systems, respectively, which are rarely seen among aplysiatoxins. Both compounds exhibited potent blocking activity against Kv1.5 with IC 50 values of 6.94 ± 0.26 and 0.30 ± 0.05 μM, respectively. These findings suggest the potential of aplysiatoxin analogues in modulating ionic channels and also provide links between the DAT target, protein kinase C, and cell regulation.

Importance of climate change-physical forcing on the increase of cyanobacterial blooms in a small, stratified lake

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Dolores Planas

2016-03-01

Full Text Available The community structure of planktonic cyanobacteria was studied in a dimictic lake in which recurrent summer surface algal blooms have frequently occurred since the beginning of this millennium. In eutrophic-hypereutrophic lakes, epilimnetic cyanobacterial blooms are promoted by increased ambient temperatures and water column thermal stability, which favour the vertical migration of buoyancy-regulating cyanobacteria. Here we propose that intensified external energy (wind that alters thermocline stability could explain the occurence of heavy blooms in the surface of lakes with low external nutrient loading. Specifically, we hypothesized that: i in small stratified lakes with low external nutrient sources, cyanobacterial growth primarily occurs near the lake bottom, where phosphorus is more abundant and light is available; ii we additionally hypothesized that turbulence induced by strong winds increases the amplitude and energy of metalimnetic internal waves and entrains meta- and hypolimnetic water,  rich in nutrients and cyanobacteria, into the epilimnion. The study was done in a small lake (45 Ha, maximum and mean depth 7.2 m and 4.3 m, respectively with mean epilimnetic dissolved phosphorus concentrations ≈ 4 μg L-1 and chlorophyll α ≈ 8 μg L-1.  Vertical temperature profiles during the open season were continuously registered using thermistors.  Weekly vertical profiles of light transmission, phytoplankton distribution and water chemistry were also taken. On one occasion, these variables were measured throughout a continuous 24 h cycle. Results demonstrated that summer cyanobacterial blooms were dominated by Plankthotrix spp., which began their cycle in late spring at the bottom of the lake, and grew to form dense metalimnetic biomass peaks. Time series analysis of isotherms and the Lake number indicated that internal metalimnetic waves (seiches were present through the summer. During the diel sampling cycle, we found that medium to

Epilithic Cyanobacterial Communities of a Marine Tropical Beach Rock (Heron Island, Great Barrier Reef): Diversity and Diazotrophy▿

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Díez, Beatriz; Bauer, Karolina; Bergman, Birgitta

2007-01-01

The diversity and nitrogenase activity of epilithic marine microbes in a Holocene beach rock (Heron Island, Great Barrier Reef, Australia) with a proposed biological calcification “microbialite” origin were examined. Partial 16S rRNA gene sequences from the dominant mat (a coherent and layered pink-pigmented community spread over the beach rock) and biofilms (nonstratified, differently pigmented microbial communities of small shallow depressions) were retrieved using denaturing gradient gel electrophoresis (DGGE), and a clone library was retrieved from the dominant mat. The 16S rRNA gene sequences and morphological analyses revealed heterogeneity in the cyanobacterial distribution patterns. The nonheterocystous filamentous genus Blennothrix sp., phylogenetically related to Lyngbya, dominated the mat together with unidentified nonheterocystous filaments of members of the Pseudanabaenaceae and the unicellular genus Chroococcidiopsis. The dominance and three-dimensional intertwined distribution of these organisms were confirmed by nonintrusive scanning microscopy. In contrast, the less pronounced biofilms were dominated by the heterocystous cyanobacterial genus Calothrix, two unicellular Entophysalis morphotypes, Lyngbya spp., and members of the Pseudanabaenaceae family. Cytophaga-Flavobacterium-Bacteroides and Alphaproteobacteria phylotypes were also retrieved from the beach rock. The microbial diversity of the dominant mat was accompanied by high nocturnal nitrogenase activities (as determined by in situ acetylene reduction assays). A new DGGE nifH gene optimization approach for cyanobacterial nitrogen fixers showed that the sequences retrieved from the dominant mat were related to nonheterocystous uncultured cyanobacterial phylotypes, only distantly related to sequences of nitrogen-fixing cultured cyanobacteria. These data stress the occurrence and importance of nonheterocystous epilithic cyanobacteria, and it is hypothesized that such epilithic cyanobacteria

Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells.

Science.gov (United States)

Miranda, Ana F; Taha, Mohamed; Wrede, Digby; Morrison, Paul; Ball, Andrew S; Stevenson, Trevor; Mouradov, Aidyn

2015-01-01

Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive. This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its genetically modified derivatives that have been altered to enable secretion of free fatty acids into growth media. Secreted free fatty acids are potentially used by fungal cells as a carbon source for growth and ex-novo production of lipids. For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures. The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus. Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

Controlling harmful cyanobacterial blooms in a world experiencing anthropogenic and climatic-induced change

Energy Technology Data Exchange (ETDEWEB)

Paerl, Hans W., E-mail: hpaerl@email.unc.edu; Hall, Nathan S.; Calandrino, Elizabeth S.

2011-04-15

Harmful (toxic, food web altering, hypoxia generating) cyanobacterial algal blooms (CyanoHABs) are proliferating world-wide due to anthropogenic nutrient enrichment, and they represent a serious threat to the use and sustainability of our freshwater resources. Traditionally, phosphorus (P) input reductions have been prescribed to control CyanoHABs, because P limitation is widespread and some CyanoHABs can fix atmospheric nitrogen (N{sub 2}) to satisfy their nitrogen (N) requirements. However, eutrophying systems are increasingly plagued with non N{sub 2} fixing CyanoHABs that are N and P co-limited or even N limited. In many of these systems N loads are increasing faster than P loads. Therefore N and P input constraints are likely needed for long-term CyanoHAB control in such systems. Climatic changes, specifically warming, increased vertical stratification, salinization, and intensification of storms and droughts play additional, interactive roles in modulating CyanoHAB frequency, intensity, geographic distribution and duration. In addition to having to consider reductions in N and P inputs, water quality managers are in dire need of effective tools to break the synergy between nutrient loading and hydrologic regimes made more favorable for CyanoHABs by climate change. The more promising of these tools make affected waters less hospitable for CyanoHABs by 1) altering the hydrology to enhance vertical mixing and/or flushing and 2) decreasing nutrient fluxes from organic rich sediments by physically removing the sediments or capping sediments with clay. Effective future CyanoHAB management approaches must incorporate both N and P loading dynamics within the context of altered thermal and hydrologic regimes associated with climate change. - Research Highlights: {yields} Toxic cyanobacterial blooms (CyanoHABs) increasingly threaten global water supplies. {yields} Human (nutrient) and climate (hydrology, temperature) changes synergistically promote CyanoHABs. {yields

The production of cyanobacterial carbon under nitrogen-limited cultivation and its potential for nitrate removal.

Science.gov (United States)

Huang, Yingying; Li, Panpan; Chen, Guiqin; Peng, Lin; Chen, Xuechu

2018-01-01

Harmful cyanobacterial blooms (CyanoHABs) represent a serious threat to aquatic ecosystems. A beneficial use for these harmful microorganisms would be a promising resolution of this urgent issue. This study applied a simple method, nitrogen limitation, to cultivate cyanobacteria aimed at producing cyanobacterial carbon for denitrification. Under nitrogen-limited conditions, the common cyanobacterium, Microcystis, efficiently used nitrate, and had a higher intracellular C/N ratio. More importantly, organic carbons easily leached from its dry powder; these leachates were biodegradable and contained a larger amount of dissolved organic carbon (DOC) and carbohydrates, but a smaller amount of dissolved total nitrogen (DTN) and proteins. When applied to an anoxic system with a sediment-water interface, a significant increase of the specific NO X - -N removal rate was observed that was 14.2 times greater than that of the control. This study first suggests that nitrogen-limited cultivation is an efficient way to induce organic and carbohydrate accumulation in cyanobacteria, as well as a high C/N ratio, and that these cyanobacteria can act as a promising carbon source for denitrification. The results indicate that application as a carbon source is not only a new way to utilize cyanobacteria, but it also contributes to nitrogen removal in aquatic ecosystems, further limiting the proliferation of CyanoHABs. Copyright © 2017. Published by Elsevier Ltd.

A curated database of cyanobacterial strains relevant for modern taxonomy and phylogenetic studies.

Science.gov (United States)

Ramos, Vitor; Morais, João; Vasconcelos, Vitor M

2017-04-25

The dataset herein described lays the groundwork for an online database of relevant cyanobacterial strains, named CyanoType (http://lege.ciimar.up.pt/cyanotype). It is a database that includes categorized cyanobacterial strains useful for taxonomic, phylogenetic or genomic purposes, with associated information obtained by means of a literature-based curation. The dataset lists 371 strains and represents the first version of the database (CyanoType v.1). Information for each strain includes strain synonymy and/or co-identity, strain categorization, habitat, accession numbers for molecular data, taxonomy and nomenclature notes according to three different classification schemes, hierarchical automatic classification, phylogenetic placement according to a selection of relevant studies (including this), and important bibliographic references. The database will be updated periodically, namely by adding new strains meeting the criteria for inclusion and by revising and adding up-to-date metadata for strains already listed. A global 16S rDNA-based phylogeny is provided in order to assist users when choosing the appropriate strains for their studies.

Metagenomic Study of Iron Homeostasis in Iron Depositing Hot Spring Cyanobacterial Community

Science.gov (United States)

Brown, I.; Franklin H.; Tringe, S. G.; Klatt, C. G.; Bryant, D. A.; Sarkisova, S. A.; Guevara, M.

2010-01-01

Introduction: It is not clear how an iron-rich thermal hydrosphere could be hospitable to cyanobacteria, since reduced iron appears to stimulate oxidative stress in all domains of life and particularly in oxygenic phototrophs. Therefore, metagenomic study of cyanobacterial community in iron-depositing hot springs may help elucidate how oxygenic prokaryotes can withstand the extremely high concentrations of reactive oxygen species (ROS) produced by interaction between environmental Fe2+ and O2. Method: Anchor proteins from various species of cyanobacteria and some anoxygenic phototrophs were selected on the basis of their hypothetical role in Fe homeostasis and the suppression of oxidative stress and were BLASTed against the metagenomes of iron-depositing Chocolate Pots and freshwater Mushroom hot springs. Results: BLASTing proteins hypothesized to be involved in Fe homeostasis against the microbiomes from the two springs revealed that iron-depositing hot spring has a greater abundance of defensive proteins such as bacterioferritin comigratory protein (Bcp) and DNA-binding Ferritin like protein (Dps) than a fresh-water hot spring. One may speculate that the abundance of Bcp and Dps in an iron-depositing hot spring is connected to the need to suppress oxidative stress in bacteria inhabiting environments with high Fe2+ concnetration. In both springs, Bcp and Dps are concentrated within the cyanobacterial fractions of the microbial community (regardless of abundance). Fe3+ siderophore transport (from the transport system permease protein query) may be less essential to the microbial community of CP because of the high [Fe]. Conclusion: Further research is needed to confirm that these proteins are unique to photoautotrophs such as those living in iron-depositing hot spring.

Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial) Endosymbiont

Science.gov (United States)

Zheng, Weiwen; Rasmussen, Ulla; Zheng, Siping; Bao, Xiaodong; Chen, Bin; Gao, Yuan; Guan, Xiong; Larsson, John; Bergman, Birgitta

2013-01-01

Programmed cell death (PCD) is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20%) of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays), together with visualization of cytoskeleton alterations (FITC-phalloidin staining), showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20) further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom. PMID:23822984

Multiple Modes of Cell Death Discovered in a Prokaryotic (Cyanobacterial Endosymbiont.

Directory of Open Access Journals (Sweden)

Weiwen Zheng

Full Text Available Programmed cell death (PCD is a genetically-based cell death mechanism with vital roles in eukaryotes. Although there is limited consensus on similar death mode programs in prokaryotes, emerging evidence suggest that PCD events are operative. Here we present cell death events in a cyanobacterium living endophytically in the fern Azolla microphylla, suggestive of PCD. This symbiosis is characterized by some unique traits such as a synchronized development, a vertical transfer of the cyanobacterium between plant generations, and a highly eroding cyanobacterial genome. A combination of methods was used to identify cell death modes in the cyanobacterium. Light- and electron microscopy analyses showed that the proportion of cells undergoing cell death peaked at 53.6% (average 20% of the total cell population, depending on the cell type and host developmental stage. Biochemical markers used for early and late programmed cell death events related to apoptosis (Annexin V-EGFP and TUNEL staining assays, together with visualization of cytoskeleton alterations (FITC-phalloidin staining, showed that all cyanobacterial cell categories were affected by cell death. Transmission electron microscopy revealed four modes of cell death: apoptotic-like, autophagic-like, necrotic-like and autolytic-like. Abiotic stresses further enhanced cell death in a dose and time dependent manner. The data also suggest that dynamic changes in the peptidoglycan cell wall layer and in the cytoskeleton distribution patterns may act as markers for the various cell death modes. The presence of a metacaspase homolog (domain p20 further suggests that the death modes are genetically programmed. It is therefore concluded that multiple, likely genetically programmed, cell death modes exist in cyanobacteria, a finding that may be connected with the evolution of cell death in the plant kingdom.

An application of cellular organic matter to coagulation of cyanobacterial cells (Merismopedia tenuissima)

Czech Academy of Sciences Publication Activity Database

Barešová, Magdalena; Pivokonský, Martin; Novotná, Kateřina; Načeradská, Jana; Brányik, T.

2017-01-01

Roč. 122, October (2017), s. 70-77 ISSN 0043-1354 Institutional support: RVO:67985874 Keywords : algal cellular organic matter * coagulation * cyanobacterial cells * Merismopedia tenuissima * water treatment Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 6.942, year: 2016

Hydrogen production by the engineered cyanobacterial strain Nostoc PCC 7120 ΔhupW examined in a flat panel photobioreactor system.

Science.gov (United States)

Nyberg, Marcus; Heidorn, Thorsten; Lindblad, Peter

2015-12-10

Nitrogenase based hydrogen production was examined in a ΔhupW strain of the filamentous heterocystous cyanobacterium Nostoc PCC 7120, i.e., cells lacking the last step in the maturation system of the large subunit of the uptake hydrogenase and as a consequence with a non-functional uptake hydrogenase. The cells were grown in a developed flat panel photobioreactor system with 3.0L culture volume either aerobically (air) or anaerobically (Ar or 80% N2/20% Ar) and illuminated with a mixture of red and white LED. Aerobic growth of the ΔhupW strain of Nostoc PCC 7120 at 44μmolar photons m(-2)s(-1) PAR gave the highest hydrogen production of 0.7mL H2 L(-1)h(-1), 0.53mmol H2 mg chlorophyll a(-1)h(-1), and a light energy conversion efficiency of 1.2%. Anaerobic growth using 100% argon showed a maximal hydrogen production of 1.7mLL(-1)h(-1), 0.85mmol per mg chlorophyll a(-1) h(-1), and a light energy conversion efficiency of 2.7%. Altering between argon/N2 (20/80) and 100% argon phases resulted in a maximal hydrogen production at hour 128 (100% argon phase) with 6.2mL H2L(-1)h(-1), 0.71mL H2 mg chlorophyll a(-1)h(-1), and a light energy efficiency conversion of 4.0%. The highest buildup of hydrogen gas observed was 6.89% H2 (100% argon phase) of the total photobioreactor system with a maximal production of 4.85mL H2 L(-1)h(-1). The present study clearly demonstrates the potential to use purpose design cyanobacteria in developed flat panel photobioreactor systems for the direct production of the solar fuel hydrogen. Further improvements in the strain used, environmental conditions employed, and growth, production and collection systems used, are needed before a sustainable and economical cyanobacterial based hydrogen production can be realized. Copyright © 2015 Elsevier B.V. All rights reserved.

Some Like it High! Phylogenetic Diversity of High-Elevation Cyanobacterial Community from Biological Soil Crusts of Western Himalaya.

Science.gov (United States)

Čapková, Kateřina; Hauer, Tomáš; Řeháková, Klára; Doležal, Jiří

2016-01-01

The environment of high-altitudinal cold deserts of Western Himalaya is characterized by extensive development of biological soil crusts, with cyanobacteria as dominant component. The knowledge of their taxonomic composition and dependency on soil chemistry and elevation is still fragmentary. We studied the abundance and the phylogenetic diversity of the culturable cyanobacteria and eukaryotic microalgae in soil crusts along altitudinal gradients (4600-5900 m) at two sites in the dry mountains of Ladakh (SW Tibetan Plateau and Eastern Karakoram), using both microscopic and molecular approaches. The effects of environmental factors (altitude, mountain range, and soil physico-chemical parameters) on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Both phylogenetic diversity and composition of morphotypes were similar between Karakorum and Tibetan Plateau. Phylogenetic analysis of 16S rRNA gene revealed strains belonging to at least five genera. Besides clusters of common soil genera, e.g., Microcoleus, Nodosilinea, or Nostoc, two distinct clades of simple trichal taxa were newly discovered. The most abundant cyanobacterial orders were Oscillatoriales and Nostacales, whose biovolume increased with increasing elevation, while that of Chroococales decreased. Cyanobacterial species richness was low in that only 15 morphotypes were detected. The environmental factors accounted for 52 % of the total variability in microbial data, 38.7 % of which was explained solely by soil chemical properties, 14.5 % by altitude, and 8.4 % by mountain range. The elevation, soil phosphate, and magnesium were the most important predictors of soil phototrophic communities in both mountain ranges despite their different bedrocks and origin. The present investigation represents a first record on phylogenetic diversity of the cyanobacterial community of biological soil crusts from Western Himalayas and first record

Efficient assimilation of cyanobacterial nitrogen by water hyacinth.

Science.gov (United States)

Qin, Hongjie; Zhang, Zhiyong; Liu, Minhui; Wang, Yan; Wen, Xuezheng; Yan, Shaohua; Zhang, Yingying; Liu, Haiqin

2017-10-01

A 15 N labeling technique was used to study nitrogen transfer from cyanobacterium Microcystis aeruginosa to water hyacinth. 15 N atom abundance in M. aeruginosa peaked (15.52%) after cultivation in 15 N-labeled medium for 3weeks. Over 87% of algal nitrogen was transferred into water hyacinth after the 4-week co-cultivation period. The nitrogen quickly super-accumulated in the water hyacinth roots, and the labeled nitrogen was re-distributed to different organs (i.e., roots, stalks, and leaves). This study provides a new strategy for further research on cyanobacterial bloom control, nitrogen migration, and nitrogen cycle in eutrophic waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Critical review of actually available chemical compounds for prevention and management of cyanobacterial blooms

Czech Academy of Sciences Publication Activity Database

Jančula, Daniel; Maršálek, Blahoslav

2011-01-01

Roč. 85, č. 9 (2011), s. 1415-1422 ISSN 0045-6535 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : algicide * bloom management * cyanobacterial blooms Subject RIV: EF - Botanics Impact factor: 3.206, year: 2011

Transgenic tobacco plants with improved cyanobacterial Rubisco expression but no extra assembly factors grow at near wild-type rates if provided with elevated CO2.

Science.gov (United States)

Occhialini, Alessandro; Lin, Myat T; Andralojc, P John; Hanson, Maureen R; Parry, Martin A J

2016-01-01

Introducing a carbon-concentrating mechanism and a faster Rubisco enzyme from cyanobacteria into higher plant chloroplasts may improve photosynthetic performance by increasing the rate of CO2 fixation while decreasing losses caused by photorespiration. We previously demonstrated that tobacco plants grow photoautotrophically using Rubisco from Synechococcus elongatus, although the plants exhibited considerably slower growth than wild-type and required supplementary CO2 . Because of concerns that vascular plant assembly factors may not be adequate for assembly of a cyanobacterial Rubisco, prior transgenic plants included the cyanobacterial chaperone RbcX or the carboxysomal protein CcmM35. Here we show that neither RbcX nor CcmM35 is needed for assembly of active cyanobacterial Rubisco. Furthermore, by altering the gene regulatory sequences on the Rubisco transgenes, cyanobacterial Rubisco expression was enhanced and the transgenic plants grew at near wild-type growth rates, although still requiring elevated CO2 . We performed detailed kinetic characterization of the enzymes produced with and without the RbcX and CcmM35 cyanobacterial proteins. These transgenic plants exhibit photosynthetic characteristics that confirm the predicted benefits of introduction of non-native forms of Rubisco with higher carboxylation rate constants in vascular plants and the potential nitrogen-use efficiency that may be achieved provided that adequate CO2 is available near the enzyme. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Growth kinetic and fuel quality parameters as selective criterion for screening biodiesel producing cyanobacterial strains.

Science.gov (United States)

Gayathri, Manickam; Shunmugam, Sumathy; Mugasundari, Arumugam Vanmathi; Rahman, Pattanathu K S M; Muralitharan, Gangatharan

2018-01-01

The efficiency of cyanobacterial strains as biodiesel feedstock varies with the dwelling habitat. Fourteen indigenous heterocystous cyanobacterial strains from rice field ecosystem were screened based on growth kinetic and fuel parameters. The highest biomass productivity was obtained in Nostoc punctiforme MBDU 621 (19.22mg/L/day) followed by Calothrix sp. MBDU 701 (13.43mg/L/day). While lipid productivity and lipid content was highest in Nostoc spongiaeforme MBDU 704 (4.45mg/L/day and 22.5%dwt) followed by Calothrix sp. MBDU 701 (1.54mg/L/day and 10.75%dwt). Among the tested strains, Nostoc spongiaeforme MBDU 704 and Nostoc punctiforme MBDU 621 were selected as promising strains for good quality biodiesel production by Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

A coagulation-powdered activated carbon-ultrafiltration - Multiple barrier approach for removing toxins from two Australian cyanobacterial blooms

International Nuclear Information System (INIS)

Dixon, Mike B.; Richard, Yann; Ho, Lionel; Chow, Christopher W.K.; O'Neill, Brian K.; Newcombe, Gayle

2011-01-01

Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition.

The cyanobacterial metabolite nocuolin a is a natural oxadiazine that triggers apoptosis in human cancer cells.

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Kateřina Voráčová

Full Text Available Oxadiazines are heterocyclic compounds containing N-N-O or N-N-C-O system within a six membered ring. These structures have been up to now exclusively prepared via organic synthesis. Here, we report the discovery of a natural oxadiazine nocuolin A (NoA that has a unique structure based on 1,2,3-oxadiazine. We have identified this compound in three independent cyanobacterial strains of genera Nostoc, Nodularia, and Anabaena and recognized the putative gene clusters for NoA biosynthesis in their genomes. Its structure was characterized using a combination of NMR, HRMS and FTIR methods. The compound was first isolated as a positive hit during screening for apoptotic inducers in crude cyanobacterial extracts. We demonstrated that NoA-induced cell death has attributes of caspase-dependent apoptosis. Moreover, NoA exhibits a potent anti-proliferative activity (0.7-4.5 μM against several human cancer lines, with p53-mutated cell lines being even more sensitive. Since cancers bearing p53 mutations are resistant to several conventional anti-cancer drugs, NoA may offer a new scaffold for the development of drugs that have the potential to target tumor cells independent of their p53 status. As no analogous type of compound was previously described in the nature, NoA establishes a novel class of bioactive secondary metabolites.

Diversification of DnaA dependency for DNA replication in cyanobacterial evolution.

Science.gov (United States)

Ohbayashi, Ryudo; Watanabe, Satoru; Ehira, Shigeki; Kanesaki, Yu; Chibazakura, Taku; Yoshikawa, Hirofumi

2016-05-01

Regulating DNA replication is essential for all living cells. The DNA replication initiation factor DnaA is highly conserved in prokaryotes and is required for accurate initiation of chromosomal replication at oriC. DnaA-independent free-living bacteria have not been identified. The dnaA gene is absent in plastids and some symbiotic bacteria, although it is not known when or how DnaA-independent mechanisms were acquired. Here, we show that the degree of dependency of DNA replication on DnaA varies among cyanobacterial species. Deletion of the dnaA gene in Synechococcus elongatus PCC 7942 shifted DNA replication from oriC to a different site as a result of the integration of an episomal plasmid. Moreover, viability during the stationary phase was higher in dnaA disruptants than in wild-type cells. Deletion of dnaA did not affect DNA replication or cell growth in Synechocystis sp. PCC 6803 or Anabaena sp. PCC 7120, indicating that functional dependency on DnaA was already lost in some nonsymbiotic cyanobacterial lineages during diversification. Therefore, we proposed that cyanobacteria acquired DnaA-independent replication mechanisms before symbiosis and such an ancestral cyanobacterium was the sole primary endosymbiont to form a plastid precursor.

Dominance of cyanobacterial and cryptophytic assemblage correlated to CDOM at heavy metal contamination sites of Gujarat, India.

Science.gov (United States)

Patidar, Shailesh Kumar; Chokshi, Kaumeel; George, Basil; Bhattacharya, Sourish; Mishra, Sandhya

2015-01-01

Industrial clusters of Gujarat, India, generate high quantity of effluents which are received by aquatic bodies such as estuary and coastal water. In the present study, microalgal assemblage, heavy metals, and physico-chemical variables were studied from different habitats. Principal component analysis revealed that biovolume of cyanobacterial and cryptophytic community positively correlated with the heavy metal concentration (Hg, As, Zn, Fe, Mo, Ni, and Co) and chromophoric dissolved organic matter (CDOM) under hypoxic environment. Green algae and diatoms dominated at comparatively lower nitrate concentration which was positively associated with Pb and Mn.

Association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of Microcoleus chthonoplastes in hypersaline cyanobacterial mats

Science.gov (United States)

D'Amelio, E. D.; Cohen, Y.; Des Marais, D. J.

1987-01-01

An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8-0.9 micrometer wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300-1200 micrometers, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur

Chloroplast two-component systems: evolution of the link between photosynthesis and gene expression.

Science.gov (United States)

Puthiyaveetil, Sujith; Allen, John F

2009-06-22

Two-component signal transduction, consisting of sensor kinases and response regulators, is the predominant signalling mechanism in bacteria. This signalling system originated in prokaryotes and has spread throughout the eukaryotic domain of life through endosymbiotic, lateral gene transfer from the bacterial ancestors and early evolutionary precursors of eukaryotic, cytoplasmic, bioenergetic organelles-chloroplasts and mitochondria. Until recently, it was thought that two-component systems inherited from an ancestral cyanobacterial symbiont are no longer present in chloroplasts. Recent research now shows that two-component systems have survived in chloroplasts as products of both chloroplast and nuclear genes. Comparative genomic analysis of photosynthetic eukaryotes shows a lineage-specific distribution of chloroplast two-component systems. The components and the systems they comprise have homologues in extant cyanobacterial lineages, indicating their ancient cyanobacterial origin. Sequence and functional characteristics of chloroplast two-component systems point to their fundamental role in linking photosynthesis with gene expression. We propose that two-component systems provide a coupling between photosynthesis and gene expression that serves to retain genes in chloroplasts, thus providing the basis of cytoplasmic, non-Mendelian inheritance of plastid-associated characters. We discuss the role of this coupling in the chronobiology of cells and in the dialogue between nuclear and cytoplasmic genetic systems.

Nodularin, a cyanobacterial toxin, is synthesized in planta by symbiotic Nostoc sp.

Science.gov (United States)

Gehringer, Michelle M; Adler, Lewis; Roberts, Alexandra A; Moffitt, Michelle C; Mihali, Troco K; Mills, Toby J T; Fieker, Claus; Neilan, Brett A

2012-10-01

The nitrogen-fixing bacterium, Nostoc, is a commonly occurring cyanobacterium often found in symbiotic associations. We investigated the potential of cycad cyanobacterial endosymbionts to synthesize microcystin/nodularin. Endosymbiont DNA was screened for the aminotransferase domain of the toxin biosynthesis gene clusters. Five endosymbionts carrying the gene were screened for bioactivity. Extracts of two isolates inhibited protein phosphatase 2A and were further analyzed using electrospray ionization mass spectrometry (ESI-MS)/MS. Nostoc sp. 'Macrozamia riedlei 65.1' and Nostoc sp. 'Macrozamia serpentina 73.1' both contained nodularin. High performance liquid chromatography (HPLC) HESI-MS/MS analysis confirmed the presence of nodularin at 9.55±2.4 ng μg-1 chlorophyll a in Nostoc sp. 'Macrozamia riedlei 65.1' and 12.5±8.4 ng μg-1 Chl a in Nostoc sp. 'Macrozamia serpentina 73.1' extracts. Further scans indicated the presence of the rare isoform [L-Har(2)] nodularin, which contains L-homoarginine instead of L-arginine. Nodularin was also present at 1.34±0.74 ng ml(-1) (approximately 3 pmol per g plant ww) in the methanol root extracts of M. riedlei MZ65, while the presence of [L-Har(2)] nodularin in the roots of M. serpentina MZ73 was suggested by HPLC HESI-MS/MS analysis. The ndaA-B and ndaF genomic regions were sequenced to confirm the presence of the hybrid polyketide/non-ribosomal gene cluster. A seven amino-acid insertion into the NdaA-C1 domain of N. spumigena NSOR10 protein was observed in all endosymbiont-derived sequences, suggesting the transfer of the nda cluster from N. spumigena to terrestrial Nostoc species. This study demonstrates the synthesis of nodularin and [L-Har(2)] nodularin in a non-Nodularia species and the production of cyanobacterial hepatotoxin by a symbiont in planta.

Controlling internal phosphorus loading in lakes by physical methods to reduce cyanobacterial blooms: a review

Czech Academy of Sciences Publication Activity Database

Bormans, M.; Maršálek, Blahoslav; Jančula, Daniel

2016-01-01

Roč. 50, č. 3 (2016), s. 407-422 ISSN 1386-2588 Institutional support: RVO:67985939 Keywords : internal P loading * cyanobacterial control * physical in-lake restoration methods * adverse impacts on biota Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.500, year: 2016

Satellite monitoring of cyanobacterial harmful algal bloom frequency in recreational waters and drinking water sources

Science.gov (United States)

Cyanobacterial harmful algal blooms (cyanoHABs) cause extensive problems in lakes worldwide, including human and ecological health risks, anoxia and fish kills, and taste and odor problems. CyanoHABs are a particular concern because of their dense biomass and the risk of expos...

The Holocene sedimentary record of cyanobacterial glycolipids in the Baltic Sea: an evaluation of their application as tracers of past nitrogen fixation

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M. Sollai

2017-12-01

Full Text Available Heterocyst glycolipids (HGs are lipids exclusively produced by heterocystous dinitrogen-fixing cyanobacteria. The Baltic Sea is an ideal environment to study the distribution of HGs and test their potential as biomarkers because of its recurring summer phytoplankton blooms, dominated by a few heterocystous cyanobacterial species of the genera Nodularia and Aphanizomenon. A multi-core and a gravity core from the Gotland Basin were analyzed to determine the abundance and distribution of a suite of selected HGs at a high resolution to investigate the changes in past cyanobacterial communities during the Holocene. The HG distribution of the sediments deposited during the Modern Warm Period (MoWP was compared with those of cultivated heterocystous cyanobacteria, including those isolated from Baltic Sea waters, revealing high similarity. However, the abundance of HGs dropped substantially with depth, and this may be caused by either a decrease in the occurrence of the cyanobacterial blooms or diagenesis, resulting in partial destruction of the HGs. The record also shows that the HG distribution has remained stable since the Baltic turned into a brackish semi-enclosed basin ∼ 7200 cal. yr BP. This suggests that the heterocystous cyanobacterial species composition remained relatively stable as well. During the earlier freshwater phase of the Baltic (i.e., the Ancylus Lake and Yoldia Sea phases, the distribution of the HGs varied much more than in the subsequent brackish phase, and the absolute abundance of HGs was much lower than during the brackish phase. This suggests that the cyanobacterial community adjusted to the different environmental conditions in the basin. Our results confirm the potential of HGs as a specific biomarker of heterocystous cyanobacteria in paleo-environmental studies.

Spatial patterns and links between microbial community composition and function in cyanobacterial mats

KAUST Repository

Alnajjar, Mohammad Ahmad; Ramette, Alban; Kü hl, Michael; Hamza, Waleed; Klatt, Judith M.; Polerecky, Lubos

2014-01-01

We imaged reflectance and variable fluorescence in 25 cyanobacterial mats from four distant sites around the globe to assess, at different scales of resolution, spatial variabilities in the physiological parameters characterizing their photosynthetic capacity, including the absorptivity by chlorophyll a (Achl), maximum quantum yield of photosynthesis (Ymax), and light acclimation irradiance (Ik). Generally, these parameters significantly varied within individual mats on a sub-millimeter scale, with about 2-fold higher variability in the vertical than in the horizontal direction. The average vertical profiles of Ymax and Ik decreased with depth in the mat, while Achl exhibited a sub-surface maximum. The within-mat variability was comparable to, but often larger than, the between-sites variability, whereas the within-site variabilities (i.e., between samples from the same site) were generally lowest. When compared based on averaged values of their photosynthetic parameters, mats clustered according to their site of origin. Similar clustering was found when the community composition of the mats' cyanobacterial layers were compared by automated ribosomal intergenic spacer analysis (ARISA), indicating a significant link between the microbial community composition and function. Although this link is likely the result of community adaptation to the prevailing site-specific environmental conditions, our present data is insufficient to identify the main factors determining these patterns. Nevertheless, this study demonstrates that the spatial variability in the photosynthetic capacity and light acclimation of benthic phototrophic microbial communities is at least as large on a sub-millimeter scale as it is on a global scale, and suggests that this pattern of variability scaling is similar for the microbial community composition. © 2014 Al-Najjar, Ramette, Kühl, Hamza, Klatt and Polerecky.

Spatial patterns and links between microbial community composition and function in cyanobacterial mats

KAUST Repository

Alnajjar, Mohammad Ahmad

2014-08-06

We imaged reflectance and variable fluorescence in 25 cyanobacterial mats from four distant sites around the globe to assess, at different scales of resolution, spatial variabilities in the physiological parameters characterizing their photosynthetic capacity, including the absorptivity by chlorophyll a (Achl), maximum quantum yield of photosynthesis (Ymax), and light acclimation irradiance (Ik). Generally, these parameters significantly varied within individual mats on a sub-millimeter scale, with about 2-fold higher variability in the vertical than in the horizontal direction. The average vertical profiles of Ymax and Ik decreased with depth in the mat, while Achl exhibited a sub-surface maximum. The within-mat variability was comparable to, but often larger than, the between-sites variability, whereas the within-site variabilities (i.e., between samples from the same site) were generally lowest. When compared based on averaged values of their photosynthetic parameters, mats clustered according to their site of origin. Similar clustering was found when the community composition of the mats\\' cyanobacterial layers were compared by automated ribosomal intergenic spacer analysis (ARISA), indicating a significant link between the microbial community composition and function. Although this link is likely the result of community adaptation to the prevailing site-specific environmental conditions, our present data is insufficient to identify the main factors determining these patterns. Nevertheless, this study demonstrates that the spatial variability in the photosynthetic capacity and light acclimation of benthic phototrophic microbial communities is at least as large on a sub-millimeter scale as it is on a global scale, and suggests that this pattern of variability scaling is similar for the microbial community composition. © 2014 Al-Najjar, Ramette, Kühl, Hamza, Klatt and Polerecky.

Dissection of Microbial Community Functions during a Cyanobacterial Bloom in the Baltic Sea via Metatranscriptomics

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Carlo Berg

2018-02-01

Full Text Available Marine and brackish surface waters are highly dynamic habitats that undergo repeated seasonal variations in microbial community composition and function throughout time. While succession of the various microbial groups has been well investigated, little is known about the underlying gene-expression of the microbial community. We investigated microbial interactions via metatranscriptomics over a spring to fall seasonal cycle in the brackish Baltic Sea surface waters, a temperate brackish water ecosystem periodically promoting massive cyanobacterial blooms, which have implications for primary production, nutrient cycling, and expansion of hypoxic zones. Network analysis of the gene expression of all microbes from 0.22 to 200 μm in size and of the major taxonomic groups dissected the seasonal cycle into four components that comprised genes peaking during different periods of the bloom. Photoautotrophic nitrogen-fixing Cyanobacteria displayed the highest connectivity among the microbes, in contrast to chemoautotrophic ammonia-oxidizing Thaumarchaeota, while heterotrophs dominated connectivity among pre- and post-bloom peaking genes. The network was also composed of distinct functional connectivities, with an early season balance between carbon metabolism and ATP synthesis shifting to a dominance of ATP synthesis during the bloom, while carbon degradation, specifically through the glyoxylate shunt, characterized the post-bloom period, driven by Alphaproteobacteria as well as by Gammaproteobacteria of the SAR86 and SAR92 clusters. Our study stresses the exceptionally strong biotic driving force executed by cyanobacterial blooms on associated microbial communities in the Baltic Sea and highlights the impact cyanobacterial blooms have on functional microbial community composition.

A toxic cyanobacterial bloom in an urban coastal lake, Rio Grande do Sul state, Southern Brazil

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Luciana Retz de Carvalho

2008-12-01

Full Text Available Reports of cyanobacterial blooms developing worldwide have considerably increased, and, in most cases, the predominant toxins are microcystins. The present study reports a cyanobacterial bloom in Lake Violão, Torres, Rio Grande do Sul State, in January 2005. Samples collected on January 13, 2005, were submitted to taxonomical, toxicological, and chemical studies. The taxonomical analysis showed many different species of cyanobacteria, and that Microcystis protocystis and Sphaerocavum cf. brasiliense were dominant. Besides these, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii, and Anabaenopsis elenkinii f. circularis were also present. The toxicity of the bloom was confirmed through intraperitoneal tests in mice, and chemical analyses of bloom extracts showed that the major substance was anabaenopeptin F, followed by anabaenopeptin B, microcystin-LR, and microcystin-RR.O número de relatos de ocorrências de florações de cianobactérias em todo o mundo vem aumentando consideravelmente e na maioria desses episódios, as toxinas dominantes são as microcistinas. O presente estudo relata a ocorrência de floração na Lagoa do Violão, município de Torres, RS, em janeiro de 2005. As amostras coletadas em 13/01/2005 foram submetidas a estudos taxonômicos, toxicológicos e químicos. O exame microscópico do fitoplancton mostrou a dominância das espécies Microcystis protocystis e Sphaerocavum cf. brasiliense; foram observadas, também, Microcystis panniformis, Anabaena oumiana,Cylindrospermopsis raciborskii e Anabaenopsis elenkinii f. circularis. A toxicidade da floração foi confirmada através de ensaio intraperitonial em camundongos e a análise química de extratos obtidos da biomassa liofilizada mostrou que a substância majoritária era a anabaenopeptina F, seguida por anabaenopeptina B, microcistina-LR e microcistina-RR.

High dietary quality of non-toxic cyanobacteria for a benthic grazer and its implications for the control of cyanobacterial biofilms.

Science.gov (United States)

Groendahl, Sophie; Fink, Patrick

2017-05-18

Mass occurrences of cyanobacteria frequently cause detrimental effects to the functioning of aquatic ecosystems. Consequently, attempts haven been made to control cyanobacterial blooms through naturally co-occurring herbivores. Control of cyanobacteria through herbivores often appears to be constrained by their low dietary quality, rather than by the possession of toxins, as also non-toxic cyanobacteria are hardly consumed by many herbivores. It was thus hypothesized that the consumption of non-toxic cyanobacteria may be improved when complemented with other high quality prey. We conducted a laboratory experiment in which we fed the herbivorous freshwater gastropod Lymnaea stagnalis single non-toxic cyanobacterial and unialgal diets or a mixed diet to test if diet-mixing may enable these herbivores to control non-toxic cyanobacterial mass abundances. The treatments where L. stagnalis were fed non-toxic cyanobacteria and a mixed diet provided a significantly higher shell and soft-body growth rate than the average of all single algal, but not the non-toxic cyanobacterial diets. However, the increase in growth provided by the non-toxic cyanobacteria diets could not be related to typical determinants of dietary quality such as toxicity, nutrient stoichiometry or essential fatty acid content. These results strongly contradict previous research which describes non-toxic cyanobacteria as a low quality food resource for freshwater herbivores in general. Our findings thus have strong implications to gastropod-cyanobacteria relationships and suggest that freshwater gastropods may be able to control mass occurrences of benthic non-toxic cyanobacteria, frequently observed in eutrophied water bodies worldwide.

Use of Ion-Channel Modulating Agents to Study Cyanobacterial Na+ - K+ Fluxes

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Pomati Francesco

2004-01-01

Full Text Available Here we describe an experimental design aimed to investigate changes in total cellular levels of Na+ and K+ ions in cultures of freshwater filamentous cyanobacteria. Ion concentrations were measured in whole cells by flame photometry. Cellular Na+ levels increased exponentially with rising alkalinity, with K+ levels being maximal for optimal growth pH (~8. At standardized pH conditions, the increase in cellular Na+, as induced by NaCl at 10 mM, was coupled by the two sodium channel-modulating agents lidocaine hydrochloride at 1 &mgr;M and veratridine at 100 &mgr;M. Both the channel-blockers amiloride (1 mM and saxitoxin (1 &mgr;M, decreased cell-bound Na+ and K+ levels. Results presented demonstrate the robustness of well-defined channel blockers and channel-activators in the study of cyanobacterial Na+- K+ fluxes.

Assessment of the mutagenic potential of cyanobacterial extracts and pure cyanotoxins.

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Sieroslawska, Anna

2013-11-01

The aim of the study was to assess the mutagenic potential of extracts obtained from the cyanobacterial bloom-forming cells harvested from the water body located in Lubelszczyzna region of southeastern Poland. Three cyanotoxins, microcystin-LR, cylindrospermopsin and anatoxin-a were detected in some of the studied samples in different concentrations. All extracts were assessed for their potential mutagenic effects with the use of a short-term bacterial assay, the Ames test. Mutagenic activity was observed in four of all ten studied extracts, mainly toward the Salmonella typhimurium TA100 strain. On the contrary, the cyanotoxins in purified forms occurred not to be mutagenic or cytotoxic towards S. typhimurium TA98, TA100, TA1535, TA1537 and Escherichia coli WP2 uvrA and WP2 [pKM101] up to a concentration of 10 μg/ml. Similarly, there were no effects after bacteria exposure to the mixture of purified toxins. It has been also detected that after fractionation, genotoxic impact of previously mutagenic extracts was weaker and the highest potency in revertant induction possessed fractions containing very hydrophilic compounds. The results indicate, that while tested cyanotoxins were not directly responsible for the observed mutagenicity of the extracts analysed, some synergistic interactions with other unidentified cyanobacterial-derived factors involved in the process are possible. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of orthologous cyanobacterial aldehyde deformylating oxygenases in the production of volatile C3-C7 alkanes in engineered E. coli

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Pekka Patrikainen

2017-12-01

Full Text Available Aldehyde deformylating oxygenase (ADO is a unique enzyme found exclusively in photosynthetic cyanobacteria, which natively converts acyl aldehyde precursors into hydrocarbon products embedded in cellular lipid bilayers. This capacity has opened doors for potential biotechnological applications aiming at biological production of diesel-range alkanes and alkenes, which are compatible with the nonrenewable petroleum-derived end-products in current use. The development of production platforms, however, has been limited by the relative inefficiency of ADO enzyme, promoting research towards finding new strategies and information to be used for rational design of enhanced pathways for hydrocarbon over-expression. In this work we present an optimized approach to study different ADO orthologs derived from different cyanobacterial species in an in vivo set-up in Escherichia coli. The system enabled comparison of alternative ADOs for the production efficiency of short-chain volatile C3-C7 alkanes, propane, pentane and heptane, and provided insight on the differences in substrate preference, catalytic efficiency and limitations associated with the enzymes. The work concentrated on five ADO orthologs which represent the most extensively studied cyanobacterial species in the field, and revealed distinct differences between the enzymes. In most cases the ADO from Nostoc punctiforme PCC 73102 performed the best in respect to yields and initial rates for the production of the volatile hydrocarbons. At the other extreme, the system harboring the ADO form Synechococcus sp. RS9917 produced very low amounts of the short-chain alkanes, primarily due to poor accumulation of the enzyme in E. coli. The ADOs from Synechocystis sp. PCC 6803 and Prochlorococcus marinus MIT9313, and the corresponding variant A134F displayed less divergence, although variation between chain-length preferences could be observed. The results confirmed the general trend of ADOs having

Cyanobacterial diversity and a new acaryochloris-like symbiont from Bahamian sea-squirts.

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Susanna López-Legentil

Full Text Available Symbiotic interactions between ascidians (sea-squirts and microbes are poorly understood. Here we characterized the cyanobacteria in the tissues of 8 distinct didemnid taxa from shallow-water marine habitats in the Bahamas Islands by sequencing a fragment of the cyanobacterial 16S rRNA gene and the entire 16S-23S rRNA internal transcribed spacer region (ITS and by examining symbiont morphology with transmission electron (TEM and confocal microscopy (CM. As described previously for other species, Trididemnum spp. mostly contained symbionts associated with the Prochloron-Synechocystis group. However, sequence analysis of the symbionts in Lissoclinum revealed two unique clades. The first contained a novel cyanobacterial clade, while the second clade was closely associated with Acaryochloris marina. CM revealed the presence of chlorophyll d (chl d and phycobiliproteins (PBPs within these symbiont cells, as is characteristic of Acaryochloris species. The presence of symbionts was also observed by TEM inside the tunic of both the adult and larvae of L. fragile, indicating vertical transmission to progeny. Based on molecular phylogenetic and microscopic analyses, Candidatus Acaryochloris bahamiensis nov. sp. is proposed for this symbiotic cyanobacterium. Our results support the hypothesis that photosymbiont communities in ascidians are structured by host phylogeny, but in some cases, also by sampling location.

Specific and efficient targeting of cyanobacterial bicarbonate transporters to the inner envelope membrane of chloroplasts in Arabidopsis

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Susumu eUehara

2016-02-01

Full Text Available Installation of cyanobacterial bicarbonate transporters to the inner envelope membrane (IEM of chloroplasts in C3 plants has been thought to improve photosynthetic performance. However, the method to deliver cyanobacterial bicarbonate transporters to the chloroplast IEM remains to be established. In this study, we provide evidence that the cyanobacterial bicarbonate transporters, BicA and SbtA, can be specifically installed into the chloroplast IEM using the chloroplast IEM targeting signal in conjunction with the transit peptide. We fused the transit peptide and the mature portion of Cor413im1, whose targeting mechanism to the IEM has been characterized in detail, to either BicA or SbtA isolated from Synechocystis sp. PCC6803. Among the seven chimeric constructs tested, we confirmed that four chimeric bicarbonate transporters, designated as BicAI, BicAII, SbtAII, and SbtAIII, were expressed in Arabidopsis. Furthermore, these chimeric transporters were specifically targeted to the chloroplast IEM. They were also resistant to alkaline extraction but can be solubilized by Triton X-100, indicating that they are integral membrane proteins in the chloroplast IEM. One of the transporters, BicA, could reside in the chloroplast IEM even after removal of the IEM targeting signal. Taken together, our results indicate that the addition of IEM targeting signal, as well as the transit peptide, to bicarbonate transporters allows us to efficiently target nuclear-encoded chimeric bicarbonate transporters to the chloroplast IEM.

Photoautotrophic Polyhydroxybutyrate Granule Formation Is Regulated by Cyanobacterial Phasin PhaP in Synechocystis sp. Strain PCC 6803

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Hauf, Waldemar; Watzer, Björn; Roos, Nora; Klotz, Alexander

2015-01-01

Cyanobacteria are photoautotrophic microorganisms which fix atmospheric carbon dioxide via the Calvin-Benson cycle to produce carbon backbones for primary metabolism. Fixed carbon can also be stored as intracellular glycogen, and in some cyanobacterial species like Synechocystis sp. strain PCC 6803, polyhydroxybutyrate (PHB) accumulates when major nutrients like phosphorus or nitrogen are absent. So far only three enzymes which participate in PHB metabolism have been identified in this organism, namely, PhaA, PhaB, and the heterodimeric PHB synthase PhaEC. In this work, we describe the cyanobacterial PHA surface-coating protein (phasin), which we term PhaP, encoded by ssl2501. Translational fusion of Ssl2501 with enhanced green fluorescent protein (eGFP) showed a clear colocalization to PHB granules. A deletion of ssl2501 reduced the number of PHB granules per cell, whereas the mean PHB granule size increased as expected for a typical phasin. Although deletion of ssl2501 had almost no effect on the amount of PHB, the biosynthetic activity of PHB synthase was negatively affected. Secondary-structure prediction and circular dichroism (CD) spectroscopy of PhaP revealed that the protein consists of two α-helices, both of them associating with PHB granules. Purified PhaP forms oligomeric structures in solution, and both α-helices of PhaP contribute to oligomerization. Together, these results support the idea that Ssl2501 encodes a cyanobacterial phasin, PhaP, which regulates the surface-to-volume ratio of PHB granules. PMID:25911471

A method for examining temporal changes in cyanobacterial harmful algal bloom spatial extent using satellite remote sensing..

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Cyanobacterial harmful algal blooms (CyanoHAB) are thought to be increasing globally over the past few decades, but relatively little quantitative information is available about the spatial extent of blooms. Satellite remote sensing provides a potential technology for identifying...

Comparison of the Light-Harvesting Networks of Plant and Cyanobacterial Photosystem I

Science.gov (United States)

Şener, Melih K.; Jolley, Craig; Ben-Shem, Adam; Fromme, Petra; Nelson, Nathan; Croce, Roberta; Schulten, Klaus

2005-01-01

With the availability of structural models for photosystem I (PSI) in cyanobacteria and plants it is possible to compare the excitation transfer networks in this ubiquitous photosystem from two domains of life separated by over one billion years of divergent evolution, thus providing an insight into the physical constraints that shape the networks' evolution. Structure-based modeling methods are used to examine the excitation transfer kinetics of the plant PSI-LHCI supercomplex. For this purpose an effective Hamiltonian is constructed that combines an existing cyanobacterial model for structurally conserved chlorophylls with spectral information for chlorophylls in the Lhca subunits. The plant PSI excitation migration network thus characterized is compared to its cyanobacterial counterpart investigated earlier. In agreement with observations, an average excitation transfer lifetime of ∼49 ps is computed for the plant PSI-LHCI supercomplex with a corresponding quantum yield of 95%. The sensitivity of the results to chlorophyll site energy assignments is discussed. Lhca subunits are efficiently coupled to the PSI core via gap chlorophylls. In contrast to the chlorophylls in the vicinity of the reaction center, previously shown to optimize the quantum yield of the excitation transfer process, the orientational ordering of peripheral chlorophylls does not show such optimality. The finding suggests that after close packing of chlorophylls was achieved, constraints other than efficiency of the overall excitation transfer process precluded further evolution of pigment ordering. PMID:15994896

Temperature and cyanobacterial bloom biomass influence phosphorous cycling in eutrophic lake sediments.

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Mo Chen

Full Text Available Cyanobacterial blooms frequently occur in freshwater lakes, subsequently, substantial amounts of decaying cyanobacterial bloom biomass (CBB settles onto the lake sediments where anaerobic mineralization reactions prevail. Coupled Fe/S cycling processes can influence the mobilization of phosphorus (P in sediments, with high releases often resulting in eutrophication. To better understand eutrophication in Lake Taihu (PRC, we investigated the effects of CBB and temperature on phosphorus cycling in lake sediments. Results indicated that added CBB not only enhanced sedimentary iron reduction, but also resulted in a change from net sulfur oxidation to sulfate reduction, which jointly resulted in a spike of soluble Fe(II and the formation of FeS/FeS2. Phosphate release was also enhanced with CBB amendment along with increases in reduced sulfur. Further release of phosphate was associated with increases in incubation temperature. In addition, CBB amendment resulted in a shift in P from the Fe-adsorbed P and the relatively unreactive Residual-P pools to the more reactive Al-adsorbed P, Ca-bound P and organic-P pools. Phosphorus cycling rates increased on addition of CBB and were higher at elevated temperatures, resulting in increased phosphorus release from sediments. These findings suggest that settling of CBB into sediments will likely increase the extent of eutrophication in aquatic environments and these processes will be magnified at higher temperatures.

Large red cyanobacterial mats (Spirulina subsalsa Oersted ex Gomont in the shallow sublittoral of the southern Baltic

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Piotr Balazy

2014-06-01

Full Text Available We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other cyanobacteria, diatoms and nematode species were also present. After a few days in the laboratory, the red trichomes of S. subsalsa started to turn blue-green in colour, suggesting the strong chromatic acclimation abilities of this species.

Nodularin, a cyanobacterial toxin, is synthesized in planta by symbiotic Nostoc sp.

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Gehringer, Michelle M; Adler, Lewis; Roberts, Alexandra A; Moffitt, Michelle C; Mihali, Troco K; Mills, Toby J T; Fieker, Claus; Neilan, Brett A

2012-01-01

The nitrogen-fixing bacterium, Nostoc, is a commonly occurring cyanobacterium often found in symbiotic associations. We investigated the potential of cycad cyanobacterial endosymbionts to synthesize microcystin/nodularin. Endosymbiont DNA was screened for the aminotransferase domain of the toxin biosynthesis gene clusters. Five endosymbionts carrying the gene were screened for bioactivity. Extracts of two isolates inhibited protein phosphatase 2A and were further analyzed using electrospray ionization mass spectrometry (ESI-MS)/MS. Nostoc sp. ‘Macrozamia riedlei 65.1' and Nostoc sp. ‘Macrozamia serpentina 73.1' both contained nodularin. High performance liquid chromatography (HPLC) HESI-MS/MS analysis confirmed the presence of nodularin at 9.55±2.4 ng μg−1 chlorophyll a in Nostoc sp. ‘Macrozamia riedlei 65.1' and 12.5±8.4 ng μg−1 Chl a in Nostoc sp. ‘Macrozamia serpentina 73.1' extracts. Further scans indicated the presence of the rare isoform [L-Har2] nodularin, which contains ℒ-homoarginine instead of ℒ-arginine. Nodularin was also present at 1.34±0.74 ng ml−1 (approximately 3 pmol per g plant ww) in the methanol root extracts of M. riedlei MZ65, while the presence of [L-Har2] nodularin in the roots of M. serpentina MZ73 was suggested by HPLC HESI-MS/MS analysis. The ndaA-B and ndaF genomic regions were sequenced to confirm the presence of the hybrid polyketide/non-ribosomal gene cluster. A seven amino-acid insertion into the NdaA-C1 domain of N. spumigena NSOR10 protein was observed in all endosymbiont-derived sequences, suggesting the transfer of the nda cluster from N. spumigena to terrestrial Nostoc species. This study demonstrates the synthesis of nodularin and [L-Har2] nodularin in a non-Nodularia species and the production of cyanobacterial hepatotoxin by a symbiont in planta. PMID:22456448

Comparison of Chlorella vulgaris and cyanobacterial biomass: cultivation in urban wastewater and methane production.

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Mendez, Lara; Sialve, Bruno; Tomás-Pejó, Elia; Ballesteros, Mercedes; Steyer, Jean Philippe; González-Fernández, Cristina

2016-05-01

Anaerobic digestion of microalgae is hampered by its complex cell wall. Against this background, cyanobacteria cell walls render this biomass as an ideal substrate for overcoming this drawback. The aim of the present study was to compare the growth of two cyanobacteria (Aphanizomenon ovalisporum and Anabaena planctonica) and a microalga (Chlorella vulgaris) in urban wastewater when varying the temperature (22, 27 and 32 °C). Cyanobacterial optimal growth for both strains was attained at 22 °C, while C. vulgaris did not show remarkable differences among temperatures. For all the microorganisms, ammonium removal was higher than phosphate. Biomass collected was subjected to anaerobic digestion. Methane yield of C. vulgaris was 184.8 mL CH4 g COD in(-1) while with A. ovalisporum and A. planctonica the methane production was 1.2- and 1.4-fold higher. This study showed that cyanobacteria growth rates could be comparable to microalgae while presenting the additional benefit of an increased anaerobic digestibility.

Synergistic and species-specific effects of climate change and water colour on cyanobacterial toxicity and bloom formation

NARCIS (Netherlands)

Ekvall, M.K.; Faassen, E.J.; Gustafsson, J.A.; Lurling, M.; Hansson, L.

2013-01-01

Cyanobacterial blooms are a worldwide phenomenon in both marine and freshwater ecosystems and are predicted to occur more frequently due to global climate change. However, our future water resources may also simultaneously suffer from other environmental threats such as elevated amounts of humic

Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process

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The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometr...

Some like it high! Phylogenetic diversity of high-elevation cyanobacterial community from biological soil crusts of Western Himalaya.

Czech Academy of Sciences Publication Activity Database

Čapková, K.; Hauer, T.; Řeháková, Klára; Doležal, J.

2016-01-01

Roč. 71, č. 1 (2016), s. 113-123 ISSN 0095-3628 Institutional support: RVO:60077344 Keywords : soil crusts * cyanobacterial diversity * Western Himalayas * high-elevation * desert * phosphorus Subject RIV: EH - Ecology, Behaviour Impact factor: 3.630, year: 2016

Modulation of Biochemical and Haematological Indices of Silver Carp (Hypophthalmichthys molitrix Val.) Exposed to Toxic Cyanobacterial Water Bloom

Czech Academy of Sciences Publication Activity Database

Kopp, Radovan; Palíková, M.; Navrátil, S.; Kubíček, Z.; Ziková, A.; Mareš, J.

2010-01-01

Roč. 79, č. 1 (2010), s. 135-146 ISSN 0001-7213 Institutional research plan: CEZ:AV0Z60050516 Keywords : silver carp * cyanobacterial water blooms * haematological indices Subject RIV: EF - Botanics Impact factor: 0.534, year: 2010

How physiological and physical processes contribute to the phenology of cyanobacterial blooms in large shallow lakes: A new Euler-Lagrangian coupled model.

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Feng, Tao; Wang, Chao; Wang, Peifang; Qian, Jin; Wang, Xun

2018-09-01

Cyanobacterial blooms have emerged as one of the most severe ecological problems affecting large and shallow freshwater lakes. To improve our understanding of the factors that influence, and could be used to predict, surface blooms, this study developed a novel Euler-Lagrangian coupled approach combining the Eulerian model with agent-based modelling (ABM). The approach was subsequently verified based on monitoring datasets and MODIS data in a large shallow lake (Lake Taihu, China). The Eulerian model solves the Eulerian variables and physiological parameters, whereas ABM generates the complete life cycle and transport processes of cyanobacterial colonies. This model ensemble performed well in fitting historical data and predicting the dynamics of cyanobacterial biomass, bloom distribution, and area. Based on the calculated physical and physiological characteristics of surface blooms, principal component analysis (PCA) captured the major processes influencing surface bloom formation at different stages (two bloom clusters). Early bloom outbreaks were influenced by physical processes (horizontal transport and vertical turbulence-induced mixing), whereas buoyancy-controlling strategies were essential for mature bloom outbreaks. Canonical correlation analysis (CCA) revealed the combined actions of multiple environment variables on different bloom clusters. The effects of buoyancy-controlling strategies (ISP), vertical turbulence-induced mixing velocity of colony (VMT) and horizontal drift velocity of colony (HDT) were quantitatively compared using scenario simulations in the coupled model. VMT accounted for 52.9% of bloom formations and maintained blooms over long periods, thus demonstrating the importance of wind-induced turbulence in shallow lakes. In comparison, HDT and buoyancy controlling strategies influenced blooms at different stages. In conclusion, the approach developed here presents a promising tool for understanding the processes of onshore/offshore algal

Cyanobacterial effects in Lake Ludoš, Serbia - Is preservation of a degraded aquatic ecosystem justified?

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Tokodi, Nada; Drobac, Damjana; Meriluoto, Jussi; Lujić, Jelena; Marinović, Zoran; Važić, Tamara; Nybom, Sonja; Simeunović, Jelica; Dulić, Tamara; Lazić, Gospava; Petrović, Tamaš; Vuković-Gačić, Branka; Sunjog, Karolina; Kolarević, Stoimir; Kračun-Kolarević, Margareta; Subakov-Simić, Gordana; Miljanović, Branko; Codd, Geoffrey A; Svirčev, Zorica

2018-04-20

Cyanobacteria are present in many aquatic ecosystems in Serbia. Lake Ludoš, a wetland area of international significance and an important habitat for waterbirds, has become the subject of intense research interest because of practically continuous blooming of cyanobacteria. Analyses of water samples indicated a deterioration of ecological condition and water quality, and the presence of toxin-producing cyanobacteria (the most abundant Limnothrix redekei, Pseudanabaena limnetica, Planktothrix agardhii and Microcystis spp.). Furthermore, microcystins were detected in plants and animals from the lake: in macrophyte rhizomes (Phragmites communis, Typha latifolia and Nymphaea elegans), and in the muscle, intestines, kidneys, gonads and gills of fish (Carassius gibelio). Moreover, histopathological deleterious effects (liver, kidney, gills and intestines) and DNA damage (liver and gills) were observed in fish. A potential treatment for the reduction of cyanobacterial populations employing hydrogen peroxide was tested during this study. The treatment was not effective in laboratory tests although further in-lake trials are needed to make final conclusions about the applicability of the method. Based on our observations of the cyanobacterial populations and cyanotoxins in the water, as well as other aquatic organisms and, a survey of historical data on Lake Ludoš, it can be concluded that the lake is continuously in a poor ecological state. Conservation of the lake in order to protect the waterbirds (without urgent control of eutrophication) actually endangers them and the rest of the biota in this wetland habitat, and possibly other ecosystems. Thus, urgent measures for restoration are required, so that the preservation of this Ramsar site would be meaningful. Copyright © 2018 Elsevier B.V. All rights reserved.

The cyanobacterial nitrogen fixation paradox in natural waters [version 1; referees: 2 approved

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Hans Paerl

2017-03-01

Full Text Available Nitrogen fixation, the enzymatic conversion of atmospheric N (N2 to ammonia (NH3, is a microbially mediated process by which “new” N is supplied to N-deficient water bodies. Certain bloom-forming cyanobacterial species are capable of conducting N2 fixation; hence, they are able to circumvent N limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce oxygen in photosynthesis, they are faced with a paradoxical situation, where one critically important (for supporting growth biochemical process is inhibited by another. N2-fixing cyanobacterial taxa have developed an array of biochemical, morphological, and ecological adaptations to minimize the “oxygen problem”; however, none of these allows N2 fixation to function at a high enough efficiency so that it can supply N needs at the ecosystem scale, where N losses via denitrification, burial, and advection often exceed the inputs of “new” N by N2 fixation. As a result, most marine and freshwater ecosystems exhibit chronic N limitation of primary production. Under conditions of perpetual N limitation, external inputs of N from human sources (agricultural, urban, and industrial play a central role in determining ecosystem fertility and, in the case of N overenrichment, excessive primary production or eutrophication. This points to the importance of controlling external N inputs (in addition to traditional phosphorus controls as a means of ensuring acceptable water quality and safe water supplies. Nitrogen fixation, the enzymatic conversion of atmospheric N2 to ammonia (NH3 is a  microbially-mediated process by which “new” nitrogen is supplied to N-deficient water bodies.  Certain bloom-forming cyanobacterial species are capable of conducting N2 fixation; hence they are able to circumvent nitrogen limitation in these waters. However, this anaerobic process is highly sensitive to oxygen, and since cyanobacteria produce

UVB shielding role of FeCl3 and certain cyanobacterial pigments

International Nuclear Information System (INIS)

Kumar, A.; Tyagi, M.B.; Srinivas, G.; Singh, N.; Kumar, H.D.; Sinha, R.P.; Friedrich-Alexander-Universitaet, Erlangen; Haeder, D.P.

1996-01-01

The shielding role of ferric iron (FeCl 3 ) and certain cyanobacterial pigments (a brown-colored pigment from Scytonema hofmanii culture filtrate and a pink extract from Nostoc spongiaeforme) against UVB-induced damage in the filamentous, nitrogen-fixing cyanobacterium Nostoc muscorum has been demonstrated. Addition of these colored compounds to agarose gels (1-3 mm thick) resulted in a considerable decrease in UVB transmittance through the gels. The lowest UVB transmittance (15%) occurred through a 3 mm gel containing 0.01% FeCl 3 , followed by S. hofmanii culture filtrate (40%) and N. spongiaeforme extract (50%). These substances appear to act as very efficient UVB-absorbing screens. Percent survival and 14 CO 2 uptake of N. muscorum increased significantly if UVB exposure was given on gels containing FeCl 3 or other UVB-shielding substances. The highest protection of N. muscorum was recorded with FeCl 3 , followed by S. hofmanii culture filtrate and N. spongiaeforme extract. Such UV-shielding substances if present in required concentration range may enhance the survival of cyanobacteria exposed to high levels of UVB. (author)

Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

International Nuclear Information System (INIS)

Gerard, Claudia; Poullain, Virginie

2005-01-01

In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations. - At concentrations relevant to the field, cyanobacterial toxins (natural) and atrazine (anthropogenic) are detrimental to the gastropod Potamopyrgus antipodarum, with a greater toxicity for the natural (vs anthropogenic) stressor

Variation in the response of the invasive species Potamopyrgus antipodarum (Smith) to natural (cyanobacterial toxin) and anthropogenic (herbicide atrazine) stressors

Energy Technology Data Exchange (ETDEWEB)

Gerard, Claudia [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)]. E-mail: claudia.gerard@univ-rennes1.fr; Poullain, Virginie [UMR CNRS Ecobio 6553, Equipe Physiologie et Ecophysiologie, Universite de Rennes 1, Avenue du General Leclerc, 35042 Rennes cedex (France)

2005-11-15

In the context of increasing freshwater pollution, the impact on life-traits (survival, growth and fecundity) and locomotion of Potamopyrgus antipodarum of a 5-week field-concentration exposure to the cyanobacterial toxin microcystin-LR and the triazine herbicide, atrazine was studied. Whatever the age of exposed snails (juveniles, subadults, adults), microcystin-LR induced a decrease in survival, growth and fecundity but had no effect on locomotion. Atrazine induced a decrease in locomotory activity but had no significant effect on the life-traits. These results are discussed in terms of consequences to field populations. - At concentrations relevant to the field, cyanobacterial toxins (natural) and atrazine (anthropogenic) are detrimental to the gastropod Potamopyrgus antipodarum, with a greater toxicity for the natural (vs anthropogenic) stressor.

Different physiological and photosynthetic responses of three cyanobacterial strains to light and zinc

International Nuclear Information System (INIS)

Xu, Kui; Juneau, Philippe

2016-01-01

Highlights: • The response mechanisms to high zinc was investigated among three cyanobacterial strains grown under two light regimes. • Photosystem II is more sensitive to high zinc compared to Photosystem I in the three studied strains. • High light increases the zinc uptake in two Microcystis aeruginosa strains, but not in Synechocystis sp.. • Combined high light and high zinc treatment is lethal for the toxic M. aeruginosa CPCC299. - Abstract: Zinc pollution of freshwater aquatic ecosystems is a problem in many countries, although its specific effects on phytoplankton may be influenced by other environmental factors. Light intensity varies continuously under natural conditions depending on the cloud cover and the season, and the response mechanisms of cyanobacteria to high zinc stress under different light conditions are not yet well understood. We investigated the effects of high zinc concentrations on three cyanobacterial strains (Microcystis aeruginosa CPCC299, M. aeruginosa CPCC632, and Synechocystis sp. FACHB898) grown under two light regimes. Under high light condition (HL), the three cyanobacterial strains increased their Car/Chl a ratios and non-photochemical quenching (NPQ), with CPCC299 showing the highest growth rate—suggesting a greater ability to adapt to those conditions as compared to the other two strains. Under high zinc concentrations the values of maximal (Φ_M) and operational (Φ'_M) photosystem II quantum yields, photosystem I quantum yield [Y(I)], and NPQ decreased. The following order of sensitivity to high zinc was established for the three strains studied: CPCC299 > CPCC632 > FACHB898. These different sensitivities can be partly explained by the higher internal zinc content observed in CPCC299 as compared to the other two strains. HL increased cellular zinc content and therefore increased zinc toxicity in both M. aeruginosa strains, although to a greater extent in CPCC299 than in CPCC632. Car/Chl a ratios decreased with high

Light-optimized growth of cyanobacterial cultures: Growth phases and productivity of biomass and secreted molecules in light-limited batch growth.

Science.gov (United States)

Clark, Ryan L; McGinley, Laura L; Purdy, Hugh M; Korosh, Travis C; Reed, Jennifer L; Root, Thatcher W; Pfleger, Brian F

2018-03-27

Cyanobacteria are photosynthetic microorganisms whose metabolism can be modified through genetic engineering for production of a wide variety of molecules directly from CO 2 , light, and nutrients. Diverse molecules have been produced in small quantities by engineered cyanobacteria to demonstrate the feasibility of photosynthetic biorefineries. Consequently, there is interest in engineering these microorganisms to increase titer and productivity to meet industrial metrics. Unfortunately, differing experimental conditions and cultivation techniques confound comparisons of strains and metabolic engineering strategies. In this work, we discuss the factors governing photoautotrophic growth and demonstrate nutritionally replete conditions in which a model cyanobacterium can be grown to stationary phase with light as the sole limiting substrate. We introduce a mathematical framework for understanding the dynamics of growth and product secretion in light-limited cyanobacterial cultures. Using this framework, we demonstrate how cyanobacterial growth in differing experimental systems can be easily scaled by the volumetric photon delivery rate using the model organisms Synechococcus sp. strain PCC7002 and Synechococcus elongatus strain UTEX2973. We use this framework to predict scaled up growth and product secretion in 1L photobioreactors of two strains of Synechococcus PCC7002 engineered for production of l-lactate or L-lysine. The analytical framework developed in this work serves as a guide for future metabolic engineering studies of cyanobacteria to allow better comparison of experiments performed in different experimental systems and to further investigate the dynamics of growth and product secretion. Copyright © 2018 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Molecular Diffusion through Cyanobacterial Septal Junctions

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Mercedes Nieves-Morión

2017-01-01

Full Text Available Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N2-fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the “septal junctions” (formerly known as “microplasmodesmata” linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans.

Reefs under Siege—the Rise, Putative Drivers, and Consequences of Benthic Cyanobacterial Mats

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Amanda K. Ford

2018-02-01

Full Text Available Benthic cyanobacteria have commonly been a small but integral component of coral reef ecosystems, fulfilling the critical function of introducing bioavailable nitrogen to an inherently oligotrophic environment. Though surveys may have previously neglected benthic cyanobacteria, or grouped them with more conspicuous benthic groups, emerging evidence strongly indicates that they are becoming increasingly prevalent on reefs worldwide. Some species can form mats comprised by a diverse microbial consortium which allows them to exist across a wide range of environmental conditions. This review evaluates the putative driving factors of increasing benthic cyanobacterial mats, including climate change, declining coastal water quality, iron input, and overexploitation of key consumer and ecosystem engineer species. Ongoing global environmental change can increase growth rates and toxin production of physiologically plastic benthic cyanobacterial mats, placing them at a considerable competitive advantage against reef-building corals. Once established, strong ecological feedbacks [e.g., inhibition of coral recruitment, release of dissolved organic carbon (DOC] reinforce reef degradation. The review also highlights previously overlooked implications of mat proliferation, which can extend beyond reef health and affect human health and welfare. Though identifying (opportunistic consumers of mats remains a priority, their perceived low palatability implies that herbivore management alone may be insufficient to control their proliferation and must be accompanied by local measures to improve water quality and watershed management.

On the use of metabolic control analysis in the optimization of cyanobacterial biosolar cell factories.

Science.gov (United States)

Angermayr, S Andreas; Hellingwerf, Klaas J

2013-09-26

Oxygenic photosynthesis will have a key role in a sustainable future. It is therefore significant that this process can be engineered in organisms such as cyanobacteria to construct cell factories that catalyze the (sun)light-driven conversion of CO2 and water into products like ethanol, butanol, or other biofuels or lactic acid, a bioplastic precursor, and oxygen as a byproduct. It is of key importance to optimize such cell factories to maximal efficiency. This holds for their light-harvesting capabilities under, for example, circadian illumination in large-scale photobioreactors. However, this also holds for the "dark" reactions of photosynthesis, that is, the conversion of CO2, NADPH, and ATP into a product. Here, we present an analysis, based on metabolic control theory, to estimate the optimal capacity for product formation with which such cyanobacterial cell factories have to be equipped. Engineered l-lactic acid producing Synechocystis sp. PCC6803 strains are used to identify the relation between production rate and enzymatic capacity. The analysis shows that the engineered cell factories for l-lactic acid are fully limited by the metabolic capacity of the product-forming pathway. We attribute this to the fact that currently available promoter systems in cyanobacteria lack the genetic capacity to a provide sufficient expression in single-gene doses.

Limnology and cyanobacterial diversity of high altitude lakes of Lahaul-Spiti in Himachal Pradesh, India.

Science.gov (United States)

Singh, Y; Khattar, Jis; Singh, D P; Rahi, P; Gulati, A

2014-09-01

Limnological data of four high altitude lakes from the cold desert region of Himachal Pradesh, India, has been correlated with cyanobacterial diversity. Physico-chemical characteristics and nutrient contents of the studied lakes revealed that Sissu Lake is mesotrophic while Chandra Tal, Suraj Tal and Deepak Tal are ultra-oligotrophic. Based on morphology and 16S rRNA gene sequence, a total of 20 cyanobacterial species belonging to 11 genera were identified. Canonical correspondence analysis distinguished three groups of species with respect to their occurrence and nutrient/physical environment demand. The first group, which included Nostoc linckia, N. punctiforme, Nodularia sphaerocarpa, Geitlerinema acutissimum, Limnothrix redekii, Planktothrix agardhii and Plank. clathrata, was characteristic of water with high nutrient content and high temperature. The second group, including Gloeocapsopsis pleurocapsoides, Leptolyngbya antarctica, L. frigida, Pseudanabaena frigida and N. spongiaeforme, occurred in oligotrophic water with high pH and low temperature. The distribution of third group of Cyanobium parvum, Synechocystis pevalekii, L. benthonica, L. foveolarum, L. lurida, L. valderiana, Phormidium autumnale and P. chalybeum could not be associated with a particular environmental condition because of their presence in all sampling sites.

Effect of Different Growth Conditions on Certain Biochemical Parameters of Different Cyanobacterial Strains

Directory of Open Access Journals (Sweden)

Hammouda, O. E.

2012-01-01

Full Text Available Aims: Variation in the traditional growth medium conditions to enhance the production of lipids, carbohydrates, protein and the free amino acids content of three cyanobacterial species. Methodology and Results: Three species of cyanobacteria (Anabaena laxa, Anabaena fertilissima and Nostoc muscorum were collected from the culture collection of Soils, Water and Environment Research Institute, Agriculture Research Center, Giza, Egypt, to investigate their biochemical composition under different growth conditions, using BG110 (nitrogen free as growth medium. These conditions were represented by control medium, static glucose medium with (1%, w/v, aerated medium (aerated by bubbling technique depending on CO2 normally existed in air with a concentration of 0.03%, molasses medium (0.7%, v/v and aerated medium enriched with glucose (1%, w/v. Lipid content, total carbohydrates, soluble proteins and free amino acids were determined at the previous conditions. Glucose at 0.7% (w/v was the most favorable for lipid production in A. laxa, where it exhibited the highest lipid content (427 μg/g fresh wt.. Increasing molasses concentration up to 0.7% (v/v produced an increase in lipid contents of the tested cyanobacterial strains. The highest lipid content of both N. muscorum (366.2 μg/g fresh wt. and A. laxa (357.4 μg/g fresh wt. were recorded at molasses concentrations of 0.1 and 0.7% (v/v, respectively. A. laxa expressed high significant values for both proteins (31.6 μg/mL and free amino acids (40.5 mg/g dry wt. after 6 days of incubation period under aerated enriched glucose condition (1%, w/v. Also, at the same growth conditions, A. fertilissima exhibited high significant values for carbohydrates at 4th day (876.8 mg/g dry wt.. Conclusion, significance and impact of study: Aerated enriched glucose medium (1%, w/v was the best growth medium condition used in the present study.

Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

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Cristiana Callieri

Full Text Available Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena, a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

Some Like it High! Phylogenetic Diversity of High-Elevation Cyanobacterial Community from Biological Soil Crusts of Western Himalaya

Czech Academy of Sciences Publication Activity Database

Čapková, Kateřina; Hauer, Tomáš; Řeháková, Klára; Doležal, Jiří

2016-01-01

Roč. 71, č. 1 (2016), s. 113-123 ISSN 0095-3628 R&D Projects: GA ČR GA13-13368S Institutional support: RVO:67985939 Keywords : Soil crusts * Cyanobacterial diversity * Western Himalayas Subject RIV: EH - Ecology , Behaviour Impact factor: 3.630, year: 2016

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations

OpenAIRE

Kim, Peter W.; Rockwell, Nathan C.; Freer, Lucy H.; Chang, Che-Wei; Martin, Shelley S.; Lagarias, J. Clark; Larsen, Delmar S.

2013-01-01

The ultrafast mechanisms underlying the initial photoisomerization (Pr → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-...

Cellular responses in the cyanobacterial symbiont during its vertical transfer between plant generations in the Azolla microphylla symbiosis.

Science.gov (United States)

Zheng, Weiwen; Bergman, Birgitta; Chen, Bin; Zheng, Siping; Guan, Xiong; Xiang, Guan; Rasmussen, Ulla

2009-01-01

The nitrogen-fixing symbiosis between cyanobacteria and the water fern Azolla microphylla is, in contrast to other cyanobacteria-plant symbioses, the only one of a perpetual nature. The cyanobacterium is vertically transmitted between the plant generations, via vegetative fragmentation of the host or sexually within megasporocarps. In the latter process, subsets of the cyanobacterial population living endophytically in the Azolla leaves function as inocula for the new plant generations. Using electron microscopy and immunogold-labeling, the fate of the cyanobacterium during colonization and development of the megasporocarp was revealed. On entering the indusium chamber of the megasporocarps as small-celled motile cyanobacterial filaments (hormogonia), these differentiated into large thick-walled akinetes (spores) in a synchronized manner. This process was accompanied by cytoplasmic reorganizations and the release of numerous membrane vesicles, most of which contained DNA, and the formation of a highly structured biofilm. Taken together the data revealed complex adaptations in the cyanobacterium during its transition between plant generations.

A Multiscale Mapping Assessment of Lake Champlain Cyanobacterial Harmful Algal Blooms

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Nathan Torbick

2015-09-01

Full Text Available Lake Champlain has bays undergoing chronic cyanobacterial harmful algal blooms that pose a public health threat. Monitoring and assessment tools need to be developed to support risk decision making and to gain a thorough understanding of bloom scales and intensities. In this research application, Landsat 8 Operational Land Imager (OLI, Rapid Eye, and Proba Compact High Resolution Imaging Spectrometer (CHRIS images were obtained while a corresponding field campaign collected in situ measurements of water quality. Models including empirical band ratio regressions were applied to map chlorophylla and phycocyanin concentrations; all sensors performed well with R2 and root-mean-square error (RMSE ranging from 0.76 to 0.88 and 0.42 to 1.51, respectively. The outcomes showed spatial patterns across the lake with problematic bays having phycocyanin concentrations >25 μg/L. An alert status metric tuned to the current monitoring protocol was generated using modeled water quality to illustrate how the remote sensing tools can inform a public health monitoring system. Among the sensors utilized in this study, Landsat 8 OLI holds the most promise for providing exposure information across a wide area given the resolutions, systematic observation strategy and free cost.

Cyanobacterial water bloom of Limnoraphis robusta in the Lago Mayor of Lake Titicaca. Can it develop?

Czech Academy of Sciences Publication Activity Database

Komárková, Jaroslava; Montoya, H.; Komárek, J.

2016-01-01

Roč. 764, č. 1 (2016), s. 249-258 ISSN 0018-8158. [Workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP) /17./. Kastoria, 14.09.2014-21.09.2014] Institutional support: RVO:60077344 Keywords : Titicaca Lake * cyanobacterial water bloom * Limnoraphis robusta * Diazocytes * Atitlán Lake * N:P ratio Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.056, year: 2016

Eco-epidemiological and pathological features of wildlife mortality events related to cyanobacterial bio-intoxication in the Kruger National Park, South Africa

Directory of Open Access Journals (Sweden)

Roy Bengis

2016-10-01

Full Text Available Over the past decade, several clustered, multispecies, wildlife mortality events occurred in the vicinity of two man-made earthen dams in the southern and south central regions of the Kruger National Park, South Africa. On field investigation, heavy cyanobacterial blooms were visible in these impoundments and analysis of water samples showed the dominance of Microcystis spp. (probably Microcystis aeruginosa. Macroscopic lesions seen at necropsy and histopathological lesions were compatible with a diagnosis of cyanobacterial intoxication. Laboratory toxicity tests and assays also confirmed the presence of significant levels of microcystins in water from the two dams. These outbreaks occurred during the dry autumn and early winter seasons when water levels in these dams were dropping, and a common feature was that all the affected dams were supporting a large number of hippopotamuses (Hippopotamus amphibius. It is hypothesised that hippopotamus’ urine and faeces, together with agitation of the sediments, significantly contributed to internal loading of phosphates and nitrogen – leading to eutrophication of the water in these impoundments and subsequent cyanobacterial blooms. A major cause for concern was that a number of white rhinoceros (Ceratotherium simum were amongst the victims of these bio-intoxication events. This publication discusses the eco-epidemiology and pathology of these clustered mortalities, as well as the management options considered and eventually used to address the problem.

Toxicity of complex cyanobacterial samples and their fractions in Xenopus laevis embryos and the role of microcystins

Czech Academy of Sciences Publication Activity Database

Buryšková, B.; Hilscherová, Klára; Babica, Pavel; Vršková, D.; Maršálek, Blahoslav; Bláha, Luděk

2006-01-01

Roč. 80, č. 4 (2006), s. 346-354 ISSN 0166-445X R&D Projects: GA MŠk 1M0571; GA AV ČR KJB6005411 Institutional research plan: CEZ:AV0Z60050516 Keywords : FETAX * Xenopus laevis * malformations * cyanobacterial fractions * biomarkers Subject RIV: EF - Botanics Impact factor: 2.964, year: 2006

Microcystin in cyanobacterial blooms in a Chilean lake.

Science.gov (United States)

Campos, V; Cantarero, S; Urrutia, H; Heinze, R; Wirsing, B; Neumann, U; Weckesser, J

1999-05-01

Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies.

Different physiological and photosynthetic responses of three cyanobacterial strains to light and zinc

Energy Technology Data Exchange (ETDEWEB)

Xu, Kui; Juneau, Philippe, E-mail: juneau.philippe@uqam.ca

2016-01-15

Highlights: • The response mechanisms to high zinc was investigated among three cyanobacterial strains grown under two light regimes. • Photosystem II is more sensitive to high zinc compared to Photosystem I in the three studied strains. • High light increases the zinc uptake in two Microcystis aeruginosa strains, but not in Synechocystis sp.. • Combined high light and high zinc treatment is lethal for the toxic M. aeruginosa CPCC299. - Abstract: Zinc pollution of freshwater aquatic ecosystems is a problem in many countries, although its specific effects on phytoplankton may be influenced by other environmental factors. Light intensity varies continuously under natural conditions depending on the cloud cover and the season, and the response mechanisms of cyanobacteria to high zinc stress under different light conditions are not yet well understood. We investigated the effects of high zinc concentrations on three cyanobacterial strains (Microcystis aeruginosa CPCC299, M. aeruginosa CPCC632, and Synechocystis sp. FACHB898) grown under two light regimes. Under high light condition (HL), the three cyanobacterial strains increased their Car/Chl a ratios and non-photochemical quenching (NPQ), with CPCC299 showing the highest growth rate—suggesting a greater ability to adapt to those conditions as compared to the other two strains. Under high zinc concentrations the values of maximal (Φ{sub M}) and operational (Φ'{sub M}) photosystem II quantum yields, photosystem I quantum yield [Y(I)], and NPQ decreased. The following order of sensitivity to high zinc was established for the three strains studied: CPCC299 > CPCC632 > FACHB898. These different sensitivities can be partly explained by the higher internal zinc content observed in CPCC299 as compared to the other two strains. HL increased cellular zinc content and therefore increased zinc toxicity in both M. aeruginosa strains, although to a greater extent in CPCC299 than in CPCC632. Car/Chl a ratios

Cyanobacterial life at low O(2): community genomics and function reveal metabolic versatility and extremely low diversity in a Great Lakes sinkhole mat.

Science.gov (United States)

Voorhies, A A; Biddanda, B A; Kendall, S T; Jain, S; Marcus, D N; Nold, S C; Sheldon, N D; Dick, G J

2012-05-01

Cyanobacteria are renowned as the mediators of Earth's oxygenation. However, little is known about the cyanobacterial communities that flourished under the low-O(2) conditions that characterized most of their evolutionary history. Microbial mats in the submerged Middle Island Sinkhole of Lake Huron provide opportunities to investigate cyanobacteria under such persistent low-O(2) conditions. Here, venting groundwater rich in sulfate and low in O(2) supports a unique benthic ecosystem of purple-colored cyanobacterial mats. Beneath the mat is a layer of carbonate that is enriched in calcite and to a lesser extent dolomite. In situ benthic metabolism chambers revealed that the mats are net sinks for O(2), suggesting primary production mechanisms other than oxygenic photosynthesis. Indeed, (14)C-bicarbonate uptake studies of autotrophic production show variable contributions from oxygenic and anoxygenic photosynthesis and chemosynthesis, presumably because of supply of sulfide. These results suggest the presence of either facultatively anoxygenic cyanobacteria or a mix of oxygenic/anoxygenic types of cyanobacteria. Shotgun metagenomic sequencing revealed a remarkably low-diversity mat community dominated by just one genotype most closely related to the cyanobacterium Phormidium autumnale, for which an essentially complete genome was reconstructed. Also recovered were partial genomes from a second genotype of Phormidium and several Oscillatoria. Despite the taxonomic simplicity, diverse cyanobacterial genes putatively involved in sulfur oxidation were identified, suggesting a diversity of sulfide physiologies. The dominant Phormidium genome reflects versatile metabolism and physiology that is specialized for a communal lifestyle under fluctuating redox conditions and light availability. Overall, this study provides genomic and physiologic insights into low-O(2) cyanobacterial mat ecosystems that played crucial geobiological roles over long stretches of Earth history. �

USE OF PHOSPHOLIPID FATTY ACID PROFILES TO STUDY THE MICROBIAL COMPOSITION OF CYANOBACTERIAL MATS IN CABO ROJO SOLAR SALTERNS

Science.gov (United States)

The Cabo Rojo Saltern located in the West side of Puerto Rico is a hypersaline ecosystem that consists of crystallizer ponds surrounded by series of cyanobacterial mats. Although this ecosystem harbors a variety of microorganisms not much is known about their identity and relati...

The impact of pre-oxidation with potassium permanganate on cyanobacterial organic matter removal by coagulation.

Science.gov (United States)

Naceradska, Jana; Pivokonsky, Martin; Pivokonska, Lenka; Baresova, Magdalena; Henderson, Rita K; Zamyadi, Arash; Janda, Vaclav

2017-05-01

The study investigates the effect of permanganate pre-oxidation on the coagulation of peptides/proteins of Microcystis aeruginosa which comprise a major proportion of the organic matter during cyanobacterial bloom decay. Four different permanganate dosages (0.1, 0.2, 0.4 and 0.6 mg KMnO 4 mg -1 DOC) were applied prior to coagulation by ferric sulphate. Moreover, changes in sample characteristics, such as UV 254 , DOC content and molecular weight distribution, after pre-oxidation were monitored. The results showed that permanganate pre-oxidation led to a reduction in coagulant dose, increased organic matter removals by coagulation (by 5-12% depending on permanganate dose), microcystin removal (with reductions of 91-96%) and a shift of the optimum pH range from 4.3 to 6 without to 5.5-7.3 with pre-oxidation. Degradation of organic matter into inorganic carbon and adsorption of organic matter onto hydrous MnO 2 are suggested as the main processes responsible for coagulation improvement. Moreover, permanganate prevented the formation of Fe-peptide/protein complexes that inhibit coagulation at pH about 6.2 without pre-oxidation. The study showed that carefully optimized dosing of permanganate improves cyanobacterial peptide/protein removal, with the benefit of microcystin elimination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advances in cyanobacterial polyhydroxyalkanoates production.

Science.gov (United States)

Singh, Akhilesh Kumar; Mallick, Nirupama

2017-11-01

Polyhydroxyalkanoates (PHAs) have received much attention in the current scenario due to their attractive material properties, namely biodegradability, biocompatibility, thermoplasticity, hydrophobicity, piezoelectricity and stereospecificity. All these properties make them highly competitive for various industrial applications similar to non-degradable conventional plastics. In PHA biosynthesis, PHA synthase acts as a natural catalyst for PHA polymerization process using the (R)-hydroxyacyl-CoA as substrate. Cyanobacteria can accumulate PHAs under photoautotrophic and/or mixotrophic growth conditions with organic substrates such as acetate, glucose, propionate, valerate, and so on. The natural incidence of PHA accumulation by the cyanobacteria is known since 1966. Nevertheless, PHA accumulation in cyanobacteria based on the cell biomass and volumetric productivity is critically lower than the heterotrophic bacteria. Consequently, cyanobacteria are nowadays not considered for commercial production of PHAs. Thus, strain improvements by genetic modification, new cultivation and harvesting techniques, advanced photobioreactor development, efficient and sustainable downstream processes, alternate economical carbon sources and usage of various metabolic inhibitors are suggested for enhancing cyanobacterial PHA accumulation. In addition, identification of transcriptional regulators like RNA polymerase sigma factor (SigE) and a response regulator (Rre37) together with the recent major scientific breakthrough on the existence of complete Krebs cycle in cyanobacteria would be helpful in taking PHA production from cyanobacteria to a new-fangled height in near future. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Monitoring tools and early warning system for harmful cyanobacterial blooms: Río Uruguay and Río de la Plata

Directory of Open Access Journals (Sweden)

Carla Kruk

2015-12-01

Full Text Available Potentially hazardous cyanobacterial blooming constitutes one of the most widespread problems experienced by aquatic systems worldwide. However, there are not any monitoring methods sensitive enough to be directly applicable to predict and manage blooming events. In order to fulfill this goal, both ecological and genetic concepts were combined to generate cyanobacteria monitoring tools. Two approaches were used: grouping organisms into functional groups and utilizing molecular analysis (real time quantitative PCR as indicators of the presence of genes that encode the expression of cyanotoxins (mcy. Six bi-monthly sampling campaigns were performed to evaluate the suitability of these tools (2013-2014 at six locations composed of two sites each one, ranging downstream from Salto Grande, at the River Uruguay, to Punta del Este, at the Estuary River Plate. A remarkable gradient was observed in the meteorological, physical and chemical variables, as well as higher abundances in planktonic organisms both in Salto Grande and in Punta del Este. The most abundant population of toxic species in the whole gradient were found in Salto, and in particular those belonging to the Microcystis aeruginosa complex (MAC. The most relevant environmental variables to determine the gradient and the variation in biological variables were: salinity, temperature, wind and turbidity. The results of the new indicators (presence of MAC in the plankton net and mcy genes were in agreement with the traditional ones (v.g. chlorophyll-a demonstrating being much more sensitive in cases of the most severe blooming events than in the low abundance situations. The conjunction of results was applied to the construction of a monitoring and early warning system protocol.

Occurrence and origin of mono-, di- and trimethylalkanes in modern and Holocene cyanobacterial mats from Abu Dhabi, United Arab Emirates

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Kenig, F.; Kock-van Dalen, A.C.; Rijpstra, W.I.C.; Huc, A.Y.; Leeuw, J.W. de

1995-01-01

n-Alkanes, highly branched isoprenoids, monomethylalkanes (MMAs), dimethylalkanes (DMAs), and trimethylalkanes (TMAs) are the most abundant components in the hydrocarbon fractions of extracts of four modern and two Holocene cyanobacterial mats (1500 and 5110 ± 170 y ) collected in Abu Dhabi (United

Cyanobacterial hydrogenases and biohydrogen: present status and future potential

International Nuclear Information System (INIS)

Lindblad, P.; Tamagnini, P.

2000-01-01

Molecular hydrogen (H 2 ) is an environmentally clean energy-carrier that may be a valuable alternative to the limited fossil fuel resources of today. For photobiological H 2 production, photosynthetic cyanobacteria are among the ideal candidates since they have the simplest nutritional requirements: they can grow in air (N 2 and CO 2 ), water (electrons and reductant), and mineral salts with light (solar energy) as the only source of energy. In N 2 -fixing cyanobacteria, H 2 is mainly produced by nitrogenases, but its partial consumption is quickly catalyzed by a unidirectional uptake hydrogenase. In addition, a bidirectional (reversible) enzyme may also oxidize some of the molecular hydrogen. The same enzyme will, under certain conditions, evolve H 2 Filamentous cyanobacteria have been used in bioreactors for the photobiological conversion of water to hydrogen. However, the conversion efficiencies achieved are low because the net H 2 production is the result of H 2 evolution via a nitrogenase and H 2 consumption mainly via an uptake hydrogenase. Consequently, the improvements of the conversion efficiencies are achieved e.g. through the optimization of the conditions for H 2 evolution by nitrogenase, through the production of mutants deficient in H 2 uptake activity and by an increased H 2 -evolution by a bidirectional enzyme. Symbiotic cells are of fundamental interest since they in situ 'function as a bioreactor', High metabolism, transfer of metabolite(s) from symbiont to host but almost no growth. In the present communication we will present the general knowledge about hydrogen metabolism/hydrogenases in filamentous cyanobacteria focusing on recent advances using molecular techniques, outline strategies for improving the capacity of H 2 -production by filamentous strains, and stress the importance of international cooperations and networks. (author)

Comparison of the efficacy of MODIS and MERIS data for detecting cyanobacterial blooms in the southern Caspian Sea.

Science.gov (United States)

Moradi, Masoud

2014-10-15

Medium Resolution Imaging Spectrometer (MERIS) data, Moderate Resolution Imaging Spectroradiometer (MODIS) data, and hydro-biological measurements were used to detect two very severe blooms in the southern Caspian Sea in 2005 and 2010. The MERIS Cyanobacteria Index (CIMERIS) was more reliable for detecting cyanobacterial blooms. The CIMERIS and MODIS cyanobacteria indices (CIMODIS) were compared in an effort to find a reliable method for detecting future blooms, as MERIS data were not available after April 2012. The CIMODIS had a linear relationship with and similar spatial patterns to the CIMERIS. On the CIMODIS images, extremely high biomass cyanobacteria patches were masked. A comparison of classified in situ data with the CIMODIS and Floating Algal Index (FAI) from four images of a severe bloom event in 2005 showed that the FAI is a reliable index for bloom detection over extremely dense patches. The corrected CIMODIS, the MODIS FAI and in situ data are adequate tools for cyanobacterial bloom monitoring in the southern Caspian Sea. Copyright © 2014 Elsevier Ltd. All rights reserved.

An allele of the crm gene blocks cyanobacterial circadian rhythms.

Science.gov (United States)

Boyd, Joseph S; Bordowitz, Juliana R; Bree, Anna C; Golden, Susan S

2013-08-20

The SasA-RpaA two-component system constitutes a key output pathway of the cyanobacterial Kai circadian oscillator. To date, rhythm of phycobilisome associated (rpaA) is the only gene other than kaiA, kaiB, and kaiC, which encode the oscillator itself, whose mutation causes completely arrhythmic gene expression. Here we report a unique transposon insertion allele in a small ORF located immediately upstream of rpaA in Synechococcus elongatus PCC 7942 termed crm (for circadian rhythmicity modulator), which results in arrhythmic promoter activity but does not affect steady-state levels of RpaA. The crm ORF complements the defect when expressed in trans, but only if it can be translated, suggesting that crm encodes a small protein. The crm1 insertion allele phenotypes are distinct from those of an rpaA null; crm1 mutants are able to grow in a light:dark cycle and have no detectable oscillations of KaiC phosphorylation, whereas low-amplitude KaiC phosphorylation rhythms persist in the absence of RpaA. Levels of phosphorylated RpaA in vivo measured over time are significantly altered compared with WT in the crm1 mutant as well as in the absence of KaiC. Taken together, these results are consistent with the hypothesis that the Crm polypeptide modulates a circadian-specific activity of RpaA.

Mitigating Harmful Cyanobacterial Blooms in a Human- and Climatically-Impacted World

Directory of Open Access Journals (Sweden)

Hans W. Paerl

2014-12-01

Full Text Available Bloom-forming harmful cyanobacteria (CyanoHABs are harmful from environmental, ecological and human health perspectives by outcompeting beneficial phytoplankton, creating low oxygen conditions (hypoxia, anoxia, and by producing cyanotoxins. Cyanobacterial genera exhibit optimal growth rates and bloom potentials at relatively high water temperatures; hence, global warming plays a key role in their expansion and persistence. CyanoHABs are regulated by synergistic effects of nutrient (nitrogen:N and phosphorus:P supplies, light, temperature, vertical stratification, water residence times, and biotic interactions. In most instances, nutrient control strategies should focus on reducing both N and P inputs. Strategies based on physical, chemical (nutrient and biological manipulations can be effective in reducing CyanoHABs; however, these strategies are largely confined to relatively small systems, and some are prone to ecological and environmental drawbacks, including enhancing release of cyanotoxins, disruption of planktonic and benthic communities and fisheries habitat. All strategies should consider and be adaptive to climatic variability and change in order to be effective for long-term control of CyanoHABs. Rising temperatures and greater hydrologic variability will increase growth rates and alter critical nutrient thresholds for CyanoHAB development; thus, nutrient reductions for bloom control may need to be more aggressively pursued in response to climatic changes globally.

Seasonal dynamics in dissolved organic matter, hydrogen peroxide, and cyanobacterial blooms in Lake Erie

Directory of Open Access Journals (Sweden)

Rose M. Cory

2016-04-01

Full Text Available Hydrogen peroxide (H2O2 has been suggested to influence cyanobacterial community structure and toxicity. However, no study has investigated H2O2 concentrations in freshwaters relative to cyanobacterial blooms when sources and sinks of H2O2 may be highly variable. For example, photochemical production of H2O2 from chromophoric dissolved organic matter (CDOM may vary over the course of the bloom with changing CDOM and UV light in the water column, while microbial sources and sinks of H2O2 may change with community biomass and composition. To assess relationships between H2O2 and harmful algal blooms dominated by toxic cyanobacteria in the western basin of Lake Erie, we measured H2O2 weekly at six stations from June – November, 2014 and 2015, with supporting physical, chemical, and biological water quality data. Nine additional stations across the western, eastern, and central basins of Lake Erie were sampled during August and October, 2015. CDOM sources were quantified from the fluorescence fraction of CDOM using parallel factor analysis (PARAFAC. CDOM concentration and source were significantly correlated with specific conductivity, demonstrating that discharge of terrestrially-derived CDOM from rivers can be tracked in the lake. Autochthonous sources of CDOM in the lake increased over the course of the blooms. Concentrations of H2O2 in Lake Erie ranged from 47 ± 16 nM to 1570 ± 16 nM (average of 371 ± 17 nM; n = 225, and were not correlated to CDOM concentration or source, UV light, or estimates of photochemical production of H2O2 by CDOM. Temporal patterns in H2O2 were more closely aligned with bloom dynamics in the lake. In 2014 and 2015, maximum concentrations of H2O2 were observed prior to peak water column respiration and chlorophyll a, coinciding with the onset of the widespread Microcystis blooms in late July. The spatial and temporal patterns in H2O2 concentrations suggested that production and decay of H2O2 from aquatic

Effect of different cyanobacterial biomasses and their fractions with variable microcystin content on embryonal development of carp (Cyprinus carpio L.)

Czech Academy of Sciences Publication Activity Database

Palíková, M.; Krejčí, R.; Hilscherová, Klára; Babica, Pavel; Navrátil, S.; Kopp, R.; Bláha, Luděk

2007-01-01

Roč. 81, č. 3 (2007), s. 312-318 ISSN 0166-445X R&D Projects: GA AV ČR KJB6005411 Institutional research plan: CEZ:AV0Z60050516 Keywords : cyanobacterial biomass * embryonal development * common carp Subject RIV: EF - Botanics Impact factor: 2.975, year: 2007

The Effect of Cyanobacterial Biomass Enrichment by Centrifugation and GF/C Filtration on Subsequent Microcystin Measurement

Directory of Open Access Journals (Sweden)

Shelley Rogers

2015-03-01

Full Text Available Microcystins are cyclic peptides produced by multiple cyanobacterial genera. After accumulation in the liver of animals they inhibit eukaryotic serine/threonine protein phosphatases, causing liver disease or death. Accurate detection/quantification of microcystins is essential to ensure safe water resources and to enable research on this toxin. Previous methodological comparisons have focused on detection and extraction techniques, but have not investigated the commonly used biomass enrichment steps. These enrichment steps could modulate toxin production as recent studies have demonstrated that high cyanobacterial cell densities cause increased microcystin levels. In this study, three microcystin-producing strains were processed using no cell enrichment steps (by direct freezing at three temperatures and with biomass enrichment (by centrifugation or GF/C filtration. After extraction, microcystins were analyzed using liquid chromatography-tandem mass spectrometry. All processing methods tested, except GF/C filtration, resulted in comparable microcystin quotas for all strains. The low yields observed for the filtration samples were caused by adsorption of arginine-containing microcystins to the GF/C filters. Whilst biomass enrichment did not affect microcystin metabolism over the time-frame of normal sample processing, problems associated with GF/C filtration were identified. The most widely applicable processing method was direct freezing of samples as it could be utilized in both field and laboratory environments.

A novel remote sensing algorithm to quantify phycocyanin in cyanobacterial algal blooms

International Nuclear Information System (INIS)

Mishra, S; Mishra, D R

2014-01-01

We present a novel three-band algorithm (PC 3 ) to retrieve phycocyanin (PC) pigment concentration in cyanobacteria laden inland waters. The water sample and remote sensing reflectance data used for PC 3 calibration and validation were acquired from highly turbid productive catfish aquaculture ponds. Since the characteristic PC absorption feature at 620 nm is contaminated with residual chlorophyll-a (Chl-a) absorption, we propose a coefficient (ψ) for isolating the PC absorption component at 620 nm. Results show that inclusion of the model coefficient relating Chl-a absorption at 620 nm–665 nm enables PC 3 to compensate for the confounding effect of Chl-a at the PC absorption band and considerably increases the accuracy of the PC prediction algorithm. In the current dataset, PC 3 produced the lowest mean relative error of prediction among all PC algorithms considered in this research. Moreover, PC 3 eliminates the nonlinear sensitivity issue of PC algorithms particularly at high PC range (>100 μg L −1 ). Therefore, introduction of PC 3 will have an immediate positive impact on studies monitoring inland and coastal cyanobacterial harmful algal blooms. (letter)

UVB shielding role of FeCl{sub 3} and certain cyanobacterial pigments

Energy Technology Data Exchange (ETDEWEB)

Kumar, A.; Tyagi, M.B.; Srinivas, G.; Singh, N.; Kumar, H.D. [Banaras Hindu Univ., Varanasi (India). Dept. of Botany; Sinha, R.P. [Banaras Hindu Univ., Varanasi (India). Dept. of Botany]|[Friedrich-Alexander-Universitaet, Erlangen (Germany). Institut fuer Botanik und Pharmazeutische Biologie; Haeder, D.P. [Friedrich-Alexander-Universitaet, Erlangen (Germany). Institut fuer Botanik und Pharmazeutische Biologie

1996-08-01

The shielding role of ferric iron (FeCl{sub 3}) and certain cyanobacterial pigments (a brown-colored pigment from Scytonema hofmanii culture filtrate and a pink extract from Nostoc spongiaeforme) against UVB-induced damage in the filamentous, nitrogen-fixing cyanobacterium Nostoc muscorum has been demonstrated. Addition of these colored compounds to agarose gels (1-3 mm thick) resulted in a considerable decrease in UVB transmittance through the gels. The lowest UVB transmittance (15%) occurred through a 3 mm gel containing 0.01% FeCl{sub 3}, followed by S. hofmanii culture filtrate (40%) and N. spongiaeforme extract (50%). These substances appear to act as very efficient UVB-absorbing screens. Percent survival and {sup 14}CO{sub 2} uptake of N. muscorum increased significantly if UVB exposure was given on gels containing FeCl{sub 3} or other UVB-shielding substances. The highest protection of N. muscorum was recorded with FeCl{sub 3}, followed by S. hofmanii culture filtrate and N. spongiaeforme extract. Such UV-shielding substances if present in required concentration range may enhance the survival of cyanobacteria exposed to high levels of UVB. (author).

Cyanobacterial toxins: modes of actions, fate in aquatic and soil ecosystems, phytotoxicity and bioaccumulation in agricultural crops.

Science.gov (United States)

Corbel, Sylvain; Mougin, Christian; Bouaïcha, Noureddine

2014-02-01

The occurrence of harmful cyanobacterial blooms in surface waters is often accompanied by the production of a variety of cyanotoxins. These toxins are designed to target in humans and animals specific organs on which they act: hepatotoxins (liver), neurotoxins (nervous system), cytotoxic alkaloids, and dermatotoxins (skin), but they often have important side effects too. When introduced into the soil ecosystem by spray irrigation of crops they may affect the same molecular pathways in plants having identical or similar target organs, tissues, cells or biomolecules. There are also several indications that terrestrial plants, including food crop plants, can bioaccumulate cyanotoxins and present, therefore, potential health hazards for human and animals. The number of publications concerned with phytotoxic effects of cyanotoxins on agricultural plants has increased recently. In this review, we first examine different cyanotoxins and their modes of actions in humans and mammals and occurrence of target biomolecules in vegetable organisms. Then we present environmental concentrations of cyanotoxins in freshwaters and their fate in aquatic and soil ecosystems. Finally, we highlight bioaccumulation of cyanotoxins in plants used for feed and food and its consequences on animals and human health. Overall, our review shows that the information on the effects of cyanotoxins on non-target organisms in the terrestrial environment is particularly scarce, and that there are still serious gaps in the knowledge about the fate in the soil ecosystems and phytotoxicity of these toxins. Copyright © 2013 Elsevier Ltd. All rights reserved.

Extraction and applications of cyanotoxins and other cyanobacterial secondary metabolites.

Science.gov (United States)

Haque, Fatima; Banayan, Sara; Yee, Josephine; Chiang, Yi Wai

2017-09-01

The rapid proliferation of cyanobacteria in bodies of water has caused cyanobacterial blooms, which have become an increasing cause of concern, largely due to the presence of toxic secondary metabolites (or cyanotoxins). Cyanotoxins are the toxins produced by cyanobacteria that may be harmful to surrounding wildlife. They include hepatotoxins, neurotoxins and dermatotoxins, and are classified based on the organs they affect. There are also non-toxic secondary metabolites that include chelators and UV-absorbing compounds. This paper summarizes the optimal techniques for secondary metabolite extraction and the possible useful products that can be obtained from cyanobacteria, with additional focus given to products derived from secondary metabolites. It becomes evident that the potential for their use as biocides, chelators, biofuels, biofertilizers, pharmaceuticals, food and feed, and cosmetics has not yet been comprehensively studied or extensively implemented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Systems-Level Synthetic Biology for Advanced Biofuel Production

Energy Technology Data Exchange (ETDEWEB)

Ruffing, Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jensen, Travis J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Strickland, Lucas Marshall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Meserole, Stephen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tallant, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-03-01

Cyanobacteria have been shown to be capable of producing a variety of advanced biofuels; however, product yields remain well below those necessary for large scale production. New genetic tools and high throughput metabolic engineering techniques are needed to optimize cyanobacterial metabolisms for enhanced biofuel production. Towards this goal, this project advances the development of a multiple promoter replacement technique for systems-level optimization of gene expression in a model cyanobacterial host: Synechococcus sp. PCC 7002. To realize this multiple-target approach, key capabilities were developed, including a high throughput detection method for advanced biofuels, enhanced transformation efficiency, and genetic tools for Synechococcus sp. PCC 7002. Moreover, several additional obstacles were identified for realization of this multiple promoter replacement technique. The techniques and tools developed in this project will help to enable future efforts in the advancement of cyanobacterial biofuels.

Cyanobacterial Neurotoxin BMAA and Mercury in Sharks

Directory of Open Access Journals (Sweden)

Neil Hammerschlag

2016-08-01

Full Text Available Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg, because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA, a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

Cyanobacterial Neurotoxin BMAA and Mercury in Sharks.

Science.gov (United States)

Hammerschlag, Neil; Davis, David A; Mondo, Kiyo; Seely, Matthew S; Murch, Susan J; Glover, William Broc; Divoll, Timothy; Evers, David C; Mash, Deborah C

2016-08-16

Sharks have greater risk for bioaccumulation of marine toxins and mercury (Hg), because they are long-lived predators. Shark fins and cartilage also contain β-N-methylamino-l-alanine (BMAA), a ubiquitous cyanobacterial toxin linked to neurodegenerative diseases. Today, a significant number of shark species have found their way onto the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Many species of large sharks are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products. Recent studies suggest that the consumption of shark parts may be a route to human exposure of marine toxins. Here, we investigated BMAA and Hg concentrations in fins and muscles sampled in ten species of sharks from the South Atlantic and Pacific Oceans. BMAA was detected in all shark species with only seven of the 55 samples analyzed testing below the limit of detection of the assay. Hg concentrations measured in fins and muscle samples from the 10 species ranged from 0.05 to 13.23 ng/mg. These analytical test results suggest restricting human consumption of shark meat and fins due to the high frequency and co-occurrence of two synergistic environmental neurotoxic compounds.

Health-Based Cyanotoxin Guideline Values Allow for Cyanotoxin-Based Monitoring and Efficient Public Health Response to Cyanobacterial Blooms

Science.gov (United States)

Farrer, David; Counter, Marina; Hillwig, Rebecca; Cude, Curtis

2015-01-01

Human health risks from cyanobacterial blooms are primarily related to cyanotoxins that some cyanobacteria produce. Not all species of cyanobacteria can produce toxins. Those that do often do not produce toxins at levels harmful to human health. Monitoring programs that use identification of cyanobacteria genus and species and enumeration of cyanobacterial cells as a surrogate for cyanotoxin presence can overestimate risk and lead to unnecessary health advisories. In the absence of federal criteria for cyanotoxins in recreational water, the Oregon Health Authority (OHA) developed guideline values for the four most common cyanotoxins in Oregon’s fresh waters (anatoxin-a, cylindrospermopsin, microcystins, and saxitoxins). OHA developed three guideline values for each of the cyanotoxins found in Oregon. Each of the guideline values is for a specific use of cyanobacteria-affected water: drinking water, human recreational exposure and dog recreational exposure. Having cyanotoxin guidelines allows OHA to promote toxin-based monitoring (TBM) programs, which reduce the number of health advisories and focus advisories on times and places where actual, rather than potential, risks to health exist. TBM allows OHA to more efficiently protect public health while reducing burdens on local economies that depend on water recreation-related tourism. PMID:25664510

Effect of crude extracts from cyanobacterial blooms in Lake Texcoco (Mexico) on the population growth of Brachionus calyciflorus (Rotifera).

Science.gov (United States)

Barrios, Cesar Alejandro Zamora; Nandini, S; Sarma, S S S

2017-12-01

Unlike temperate regions, tropical ecosystems are characterized by high temperatures (>18 °C) all year, promoting blooms of cyanobacteria which often produce secondary metabolites toxic to zooplankton. Nabor Carillo and the Recreational Lake are part of the saline, Lake Texcoco, in Central Mexico which is filled nowadays with treated waste water. Both water bodies are dominated by Planktothrix, Anabaenopsis, Spirulina and Microcystis. In this study we present the concentration of microcystins in these waterbodies over an annual cycle. We also evaluated the chronic effects of cyanobacterial crude extracts from both lakes on two clones of the rotifer Brachionus calyciflorus, one from Nabor Carrillo Lake and the other from a canal in the shallow, Lake Xochimilco. The experiments on population growth were performed, beginning with 10 individuals per container for each of the following treatments: control (no crude extract), concentrated crude extract, and diluted crude extract (50:50) with moderately hard water and Chlorella vulgaris in a concentration of 0.5 × 10 6  cells ml -1 . The cyanotoxin levels were measured using an ELISA test and ranged between 0.20 and 2.4 μg L -1 in the lake water. The results showed that the Recreational Lake extracts were more toxic, killing the rotifers in less than five days. The r values ranged from -1.74 to 0.48 in the presence of the crude extracts and 0.16 and 0.24 in the controls. The results have been discussed with emphasis on the importance of conducting regular studies to test ecotoxicological impacts of cyanobacterial blooms in tropical waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Course of Toxicity in the Pregnant Mouse after Exposure to the Cyanobacterial Toxin, Cylindrospermopsin: Clinical Effects, Serum Chemistries, Hematology and Histopathology

Science.gov (United States)

Cylindrospermopsin (CYN) is a toxin produced by a wide variety of fresh water cyanobacterial species worldwide and induces significant adverse effects in both livestock and humans. This study investigated the course of CYN-induced toxicity in pregnant mice exposed during either t...

Production of polyhydroxybutyrates and carbohydrates in a mixed cyanobacterial culture: Effect of nutrients limitation and photoperiods.

Science.gov (United States)

Arias, Dulce María; Uggetti, Enrica; García-Galán, María Jesús; García, Joan

2018-05-25

In the present study, different photoperiods and nutritional conditions were applied to a mixed wastewater-borne cyanobacterial culture in order to enhance the intracellular accumulation of polyhydroxybutyrates (PHBs) and carbohydrates. Two different experimental set-ups were used. In the first, the culture was permanently exposed to illumination, while in the second it was submitted to light/dark alternation (12 h cycles). In both cases, two different nutritional regimes were also evaluated, N-limitation and P-limitation. Results showed that the highest PHB concentration (104 mg L -1 ) was achieved under P limited conditions and permanent illumination, whereas the highest carbohydrate concentration (838 mg L -1 ) was obtained under N limited condition and light/dark alternation. With regard to bioplastics and biofuel generation, this study demonstrates that the accumulation of PHBs (bioplastics) and carbohydrates (potential biofuel substrate) is favored in wastewater-borne cyanobacteria under conditions where nutrients are limited. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of the cyanobacterial neurotoxin B-N-methylamino-L-alamine (BMAA) on the survival, mobility and reproduction of Daphnia magna

NARCIS (Netherlands)

Lürling, M.F.L.L.W.; Faassen, E.J.; Eenennaam, van J.S.

2011-01-01

In short-term tests and chronic life table assays, Daphnia magna was exposed to the cyanobacterial neurotoxic non-protein amino acid ß-N-methylamino-l-alanine (BMAA). BMAA was not acutely lethal to Daphnia (LC50–48h > 10 000 µg L-1), but reduced mobility (IC50–48h 40 µg L-1) and affected life

Isolation and screening of heterocystous cyanobacterial strains for biodiesel production by evaluating the fuel properties from fatty acid methyl ester (FAME) profiles.

Science.gov (United States)

Anahas, Antonyraj Matharasi Perianaika; Muralitharan, Gangatharan

2015-05-01

This study reports on the biodiesel quality parameters of eleven heterocystous cyanobacterial strains based on fatty acid methyl esters (FAME) profiles. The biomass productivity of the tested cyanobacterial strains ranged from 9.33 to 20.67 mg L(-1) d(-1) while the lipid productivity varied between 0.65 and 2.358 mg L(-1) d(-1). The highest biomass and lipid productivity was observed for Calothrix sp. MBDU 013 but its lipid content is only 11.221 in terms of percent dry weight, next to the Anabaena sphaerica MBDU 105, whose lipid content is high. To identify the most competent isolate, a multi-criteria decision analyses (MCDA) was performed by including the key chemical and physical parameters of biodiesel calculated from FAME profiles. The isolate A.sphaerica MBDU 105 is the most promising biodiesel feed stock based on decision vector through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cadmium uptake capacity of an indigenous cyanobacterial strain, Nostoc entophytum ISC32: new insight into metal uptake in microgravity-simulating conditions.

Science.gov (United States)

Alidoust, Leila; Soltani, Neda; Modiri, Sima; Haghighi, Omid; Azarivand, Aisan; Khajeh, Khosro; Shahbani Zahiri, Hossein; Vali, Hojatollah; Akbari Noghabi, Kambiz

2016-02-01

Among nine cyanobacterial strains isolated from oil-contaminated regions in southern Iran, an isolate with maximum cadmium uptake capacity was selected and identified on the basis of analysis of morphological criteria and 16S rRNA gene sequence similarity as Nostoc entophytum (with 99% similarity). The isolate was tentatively designated N. entophytum ISC32. The phylogenetic affiliation of the isolates was determined on the basis of their 16S rRNA gene sequence. The maximum amount of Cd(II) adsorbed by strain ISC32 was 302.91 mg g(-1) from an initial exposure to a solution with a Cd(II) concentration of 150 mg l(-1). The cadmium uptake by metabolically active cells of cyanobacterial strain N. entophytum ISC32, retained in a clinostat for 6 days to simulate microgravity conditions, was examined and compared with that of ground control samples. N. entophytum ISC32 under the influence of microgravity was able to take up cadmium at amounts up to 29% higher than those of controls. The activity of antioxidant enzymes including catalase and peroxidase was increased in strain ISC32 exposed to microgravity conditions in a clinostat for 6 days, as catalase activity of the cells was more than three times higher than that of controls. The activity of the peroxidase enzyme increased by 36% compared with that of the controls. Membrane lipid peroxidation was also increased in the cells retained under microgravity conditions, up to 2.89-fold higher than in non-treated cells. Images obtained using scanning electron microscopy showed that cyanobacterial cells form continuous filaments which are drawn at certain levels, while the cells placed in a clinostat appeared as round-shaped, accumulated together and distorted to some extent.

Identification of a common cyanobacterial symbiont associated with Azolla spp. through molecular and morphological characterization of free-living and symbiotic cyanobacteria.

Science.gov (United States)

Gebhardt, J S; Nierzwicki-Bauer, S A

1991-01-01

Symbiotically associated cyanobacteria from Azolla mexicana and Azolla pinnata were isolated and cultured in a free-living state. Morphological analyses revealed differences between the free-living isolates and their symbiotic counterparts, as did restriction fragment length polymorphism (RFLP) analyses with both single-copy glnA and rbcS gene probes and a multicopy psbA gene probe. RFLP analyses with Anabaena sp. strain PCC 7120 nifD excision element probes, including an xisA gene probe, detected homologous sequences in DNA extracted from the free-living isolates. Sequences homologous to these probes were not detected in DNA from the symbiotically associated cyanobacteria. These analyses indicated that the isolates were not identical to the major cyanobacterial symbiont species residing in leaf cavities of Azolla spp. Nevertheless, striking similarities between several free-living isolates were observed. In every instance, the isolate from A. pinnata displayed banding patterns virtually identical to those of free-living cultures previously isolated from Azolla caroliniana and Azolla filiculoides. These results suggest the ubiquitous presence of a culturable minor cyanobacterial symbiont in at least three species of Azolla. Images PMID:1685078

Dry limit to photosynthesis and cyanobacterial spatial pattern in the Atacama Desert

Science.gov (United States)

Warren-Rhodes, K. A.; Pointing, S. B.; Ewing, S.; Lacap, D.; Gomez-Silva, B.; Amundson, R.; Friedmann, E. I.; McKay, C. P.

2005-12-01

Hypolithic autotrophs inhabit translucent rocks in the world`'s most extreme hot and cold deserts. Across a rainfall gradient in the Atacama, we measured a three-fold decline in the molecular diversity of cyanobacterial communities and a drop in their abundance from 28% in relatively wet sites to 0.08% in the driest core. Like plants, hypoliths appear to exhibit traits of self-organized patchiness (aggregated spatial patterns) that tightly correlate with rainfall. Rare cyanobacteria in the core live slowly (3,200 y turnover times) and survive in spatially isolated patches of self-augmented fertility, with the dry limit to their survival occurring at ~Mars but may have existed in rare oases in the past. The spatial distributions of terrestrial desert microbes should be considered in the remote search for life on Mars.

Eutrophication: Present reality and future challenges for South Africa ...

African Journals Online (AJOL)

During the past 40 years, eutrophication has become an increasing threat to the usability ... biomanipulation of the food web, accurate prediction of cyanobacterial growth ... Continued monitoring and reporting of trophic status are essential to ...

Satellite monitoring of cyanobacterial harmful algal bloom ...

Science.gov (United States)

Cyanobacterial harmful algal blooms (cyanoHABs) cause extensive problems in lakes worldwide, including human and ecological health risks, anoxia and fish kills, and taste and odor problems. CyanoHABs are a particular concern because of their dense biomass and the risk of exposure to toxins in both recreational waters and drinking source waters. Successful cyanoHAB assessment by satellites may provide a first-line of defense indicator for human and ecological health protection. In this study, assessment methods were developed to determine the utility of satellite technology for detecting cyanoHAB occurrence frequency at locations of potential management interest. The European Space Agency's MEdium Resolution Imaging Spectrometer (MERIS) was evaluated to prepare for the equivalent Sentinel-3 Ocean and Land Colour Imager (OLCI) launched in 2016. Based on the 2012 National Lakes Assessment site evaluation guidelines and National Hydrography Dataset, there were 275,897 lakes and reservoirs greater than 1 hectare in the 48 U.S. states. Results from this evaluation show that 5.6 % of waterbodies were resolvable by satellites with 300 m single pixel resolution and 0.7 % of waterbodies were resolvable when a 3x3 pixel array was applied based on minimum Euclidian distance from shore. Satellite data was also spatially joined to US public water surface intake (PWSI) locations, where single pixel resolution resolved 57% of PWSI and a 3x3 pixel array resolved 33% of

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations.

Science.gov (United States)

Kim, Peter W; Rockwell, Nathan C; Freer, Lucy H; Chang, Che-Wei; Martin, Shelley S; Lagarias, J Clark; Larsen, Delmar S

2013-07-20

The ultrafast mechanisms underlying the initial photoisomerization (P r → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-state electronic surfaces. Excited-state equilibrium was not observed, as shown via the absence of a dump-induced excited-state "Le Châtelier redistribution" of excited-state populations. The importance of incorporating the inhomogeneous dynamics of Cph1 in interpreting measured transient data is discussed.

Prevention of Cyanobacterial Blooms Using Nanosilica: A Biomineralization-Inspired Strategy.

Science.gov (United States)

Xiong, Wei; Tang, Yiming; Shao, Changyu; Zhao, Yueqi; Jin, Biao; Huang, Tingting; Miao, Ya'nan; Shu, Lei; Ma, Weimin; Xu, Xurong; Tang, Ruikang

2017-11-07

Cyanobacterial blooms represent a significant threat to global water resources because blooming cyanobacteria deplete oxygen and release cyanotoxins, which cause the mass death of aquatic organisms. In nature, a large biomass volume of cyanobacteria is a precondition for a bloom, and the cyanobacteria buoyancy is a key parameter for inducing the dense accumulation of cells on the water surface. Therefore, blooms will likely be curtailed if buoyancy is inhibited. Inspired by diatoms with naturally generated silica shells, we found that silica nanoparticles can be spontaneously incorporated onto cyanobacteria in the presence of poly(diallyldimethylammonium chloride), a cationic polyelectrolyte that can simulate biosilicification proteins. The resulting cyanobacteria-SiO 2 complexes can remain sedimentary in water. This strategy significantly inhibited the photoautotrophic growth of the cyanobacteria and decreased their biomass accumulation, which could effectively suppress harmful bloom events. Consequently, several of the adverse consequences of cyanobacteria blooms in water bodies, including oxygen consumption and microcystin release, were significantly alleviated. Based on the above results, we propose that the silica nanoparticle treatment has the potential for use as an efficient strategy for preventing cyanobacteria blooms.

Cyanobacterial diversity held in microbial biological resource centers as a biotechnological asset: the case study of the newly established LEGE culture collection.

Science.gov (United States)

Ramos, Vitor; Morais, João; Castelo-Branco, Raquel; Pinheiro, Ângela; Martins, Joana; Regueiras, Ana; Pereira, Ana L; Lopes, Viviana R; Frazão, Bárbara; Gomes, Dina; Moreira, Cristiana; Costa, Maria Sofia; Brûle, Sébastien; Faustino, Silvia; Martins, Rosário; Saker, Martin; Osswald, Joana; Leão, Pedro N; Vasconcelos, Vitor M

2018-01-01

Cyanobacteria are a well-known source of bioproducts which renders culturable strains a valuable resource for biotechnology purposes. We describe here the establishment of a cyanobacterial culture collection (CC) and present the first version of the strain catalog and its online database (http://lege.ciimar.up.pt/). The LEGE CC holds 386 strains, mainly collected in coastal (48%), estuarine (11%), and fresh (34%) water bodies, for the most part from Portugal (84%). By following the most recent taxonomic classification, LEGE CC strains were classified into at least 46 genera from six orders (41% belong to the Synechococcales), several of them are unique among the phylogenetic diversity of the cyanobacteria. For all strains, primary data were obtained and secondary data were surveyed and reviewed, which can be reached through the strain sheets either in the catalog or in the online database. An overview on the notable biodiversity of LEGE CC strains is showcased, including a searchable phylogenetic tree and images for all strains. With this work, 80% of the LEGE CC strains have now their 16S rRNA gene sequences deposited in GenBank. Also, based in primary data, it is demonstrated that several LEGE CC strains are a promising source of extracellular polymeric substances (EPS). Through a review of previously published data, it is exposed that LEGE CC strains have the potential or actual capacity to produce a variety of biotechnologically interesting compounds, including common cyanotoxins or unprecedented bioactive molecules. Phylogenetic diversity of LEGE CC strains does not entirely reflect chemodiversity. Further bioprospecting should, therefore, account for strain specificity of the valuable cyanobacterial holdings of LEGE CC.

[Identification of two cyanobacterial strains isolated from the Kotel'nikovskii hot spring of the Baikal rift].

Science.gov (United States)

Sorokovnikova, E G; Tikhonova, I V; Belykh, O I; Klimenkov, I V; Likhoshvaĭ, E V

2008-01-01

Two cyanobacterial strains, Pseudanabaena sp. 0411 and Synechococcus sp. 0431, were isolated from a sample collected in the Kotel'nikovskii hot spring of the Baikal rift. According to the results of light and transmission electron microscopy, as well as of the phylogenetic analysis of the 16S rRNA gene, these cyanobacteria were classified as Pseudanabaena sp. nov. and Synechococcus bigranulatus Skuja. The constructed phylogenetic tree shows that the studied strains are positioned in the clades of cyanobacteria isolated from hydrothermal vents of Asia and New Zealand, separately from marine and freshwater members of these genera, including those isolated from Lake Baikal.

High dietary quality of non-toxic cyanobacteria for a benthic grazer and its implications for the control of cyanobacterial biofilms

OpenAIRE

Groendahl, Sophie; Fink, Patrick

2017-01-01

Background Mass occurrences of cyanobacteria frequently cause detrimental effects to the functioning of aquatic ecosystems. Consequently, attempts haven been made to control cyanobacterial blooms through naturally co-occurring herbivores. Control of cyanobacteria through herbivores often appears to be constrained by their low dietary quality, rather than by the possession of toxins, as also non-toxic cyanobacteria are hardly consumed by many herbivores. It was thus hypothesized that the consu...

Nitrogenase genes in non-cyanobacterial plankton: prevalence, diversity, and regulation in marine waters

DEFF Research Database (Denmark)

Riemann, Lasse; Farnelid, H.; Steward, G.F.

2010-01-01

Marine waters are generally considered to be nitrogen (N) limited and are therefore favourable environments for diazotrophs, i.e. organisms converting atmospheric N2 into ammonium or nitrogen oxides available for growth. In some regions, this import of N supports up to half of the primary...... productivity. Diazotrophic Cyanobacteria appear to be the major contributors to marine N2 fixation in surface waters, whereas the contribution of heterotrophic or chemoautotrophic diazotrophs to this process is usually regarded inconsequential. Culture-independent studies reveal that non......-cyanobacterial diazotrophs are diverse, widely distributed, and actively expressing the nitrogenase gene in marine and estuarine environments. The detection of nifH genes and nifH transcripts, even in N-replete marine waters, suggests that N2 fixation is an ecologically important process throughout the oceans. Because...

The responses of photosynthesis and oxygen consumption to short-term changes in temperature and irradiance in a cyanobacterial mat (Ebro Delta, Spain)

DEFF Research Database (Denmark)

Epping, E.H.G.; Kühl, Michael

2000-01-01

We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat was incu......We have evaluated the effects of short-term changes in incident irradiance and temperature on oxygenic photosynthesis and oxygen consumption in a hypersaline cyanobacterial mat from the Ebro Delta, Spain, in which Microcoleus chthonoplastes was the dominant phototrophic organism. The mat...... was incubated in the laboratory at 15, 20, 25 and 308C at incident irradiances ranging from 0 to 1000 mmol photons m22 s21. Oxygen microsensors were used to measure steady-state oxygen profiles and the rates of gross photosynthesis, which allowed the calculation of areal gross photosynthesis, areal net oxygen...... production, and oxygen consumption in the aphotic layer of the mat. The lowest surface irradiance that resulted in detectable rates of gross photosynthesis increased with increasing temperature from 50 mmol photons m22 s21 at 158C to 500 mmol photons m22 s21 at 308C. These threshold irradiances were also...

Volatile organic chemicals of a shore-dwelling cyanobacterial mat community.

Science.gov (United States)

Evans, W G

1994-02-01

The main components of a cyanobacterial mat community of a hypersaline lake shore consist of edaphic, mat-forming strains (ecophenes), and littoral strains ofOscillatoria animalis Agardh andO. subbrevis Schmidle, other microorganisms associated with these cyanobacteria, several species ofBembidion (Carabidae: Coleoptera), and two halophytic flowering plants:Puccinellia nuttalliana (salt meadow grass) andSalicornia europaea rubra (samphire). The volatile organic compounds of this community are a blend of those emitted by each of these components such as the C17 alka(e)nes, geosmin, 2-methylisoborneol,β-cyclocitral,β-ionone, dimethyl sulfide, and dimethyl trisulfide of cyanobacteria and associated microorganisms; alcohols, esters, and aldehydes usually associated with flowering plants; and possibly some insect-derived esters, particularly isopropyl tetradecanoate. The dominant compounds were: C11, C13, C15, and C17 alka(e)nes, methyl esters of C16 and C18:2 acids, isopropyl tetradecanoate, heptanal, 3-octanone and 2-nonanone, the acyclic terpene linalool, and the alcohols 1-heptanol, 1-hexanol, 1-octanol, 3-hexen-1-ol, and 2-octen-1-ol. It is concluded that this community may be distinguished from related communities by its repertoire of volatile organic compounds.

Biological Soil Crusts from Coastal Dunes at the Baltic Sea: Cyanobacterial and Algal Biodiversity and Related Soil Properties.

Science.gov (United States)

Schulz, Karoline; Mikhailyuk, Tatiana; Dreßler, Mirko; Leinweber, Peter; Karsten, Ulf

2016-01-01

Biological soil crusts (BSCs) are known as "ecosystem-engineers" that have important, multifunctional ecological roles in primary production, in nutrient and hydrological cycles, and in stabilization of soils. These communities, however, are almost unstudied in coastal dunes of the temperate zone. Hence, for the first time, the biodiversity of cyanobacterial and algal dominated BSCs collected in five dunes from the southern Baltic Sea coast on the islands Rügen and Usedom (Germany) was investigated in connection with physicochemical soil parameters. The species composition of cyanobacteria and algae was identified with direct determination of crust subsamples, cultural methods, and diatom slides. To investigate the influence of soil properties on species composition, the texture, pH, electrical conductivity, carbonate content, total contents of carbon, nitrogen, phosphorus, and the bioavailable phosphorus-fraction (PO4 (3-)) were analyzed in adjacent BSC-free surface soils at each study site. The data indicate that BSCs in coastal dunes of the southern Baltic Sea represent an ecologically important vegetation form with a surprisingly high site-specific diversity of 19 cyanobacteria, 51 non-diatom algae, and 55 diatoms. All dominant species of the genera Coleofasciculus, Lyngbya, Microcoleus, Nostoc, Hydrocoryne, Leptolyngbya, Klebsormidium, and Lobochlamys are typical aero-terrestrial cyanobacteria and algae, respectively. This first study of coastal sand dunes in the Baltic region provides compelling evidence that here the BSCs were dominated by cyanobacteria, algae, or a mixture of both. Among the physicochemical soil properties, the total phosphorus content of the BSC-free sand was the only factor that significantly influenced the cyanobacterial and algal community structure of BSCs in coastal dunes.

Algal and Cyanobacterial communities in two rivers of the province of San Luis (Argentina subjected to anthropogenic influence

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Jorgelina Daruich

2013-03-01

Full Text Available AIM: The use of biological indicators of pollution has increased in recent years as an alternative to the monitoring of water quality. Phytoplankton community selectively respond to different anthropogenic disturbances, such as water dams and the increase of nutrients coming from city centers, which leads to the eutrophication of the aquatic environment. The objective of this work was to evaluate the composition and the structure of the algal and Cyanobacterial communities in order to prove human influences by the presence of reservoirs with some degree of eutrophication and the impact of urbanization in two rivers at the Bebedero basin in San Luis province (Argentine. METHODS: Four sites were sampled: two of them were placed before dams and villages (V1 and (P1 and two after them (V2 and (P2. Each site was visited in every season of the year: summer, autumn, winter and spring. Qualitative and semi-quantitative phytoplankton samples were taken, and the frequency of occurrence was determined. Variations between pairs of sampling stations were analyzed through the Jaccard similarity and complementarity indices. RESULTS: Ninety two taxa were identified, of which diatoms were the most frequent. The most affected station was P2 with high abundance, less diversity and equitability, whereas the species more tolerant to the presence of organic matter were Melosira varians, Navicula tripunctata, Oscillatoria limosa, Gomphonema parvulum and Coelastrum microporum, and some species of euglenophytas. CONCLUSION: Therefore, the structure and composition of the algal and Cyanobacterial communities allowed us to identify sections more sensitive to human-induced alterations.

A novel cross-satellite based assessment of the spatio-temporal development of a cyanobacterial harmful algal bloom

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Page, Benjamin P.; Kumar, Abhishek; Mishra, Deepak R.

2018-04-01

As the frequency of cyanobacterial harmful algal blooms (CyanoHABs) become more common in recreational lakes and water supply reservoirs, demand for rapid detection and temporal monitoring will be imminent for effective management. The goal of this study was to demonstrate a novel and potentially operational cross-satellite based protocol for synoptic monitoring of rapidly evolving and increasingly common CyanoHABs in inland waters. The analysis involved a novel way to cross-calibrate a chlorophyll-a (Chl-a) detection model for the Landsat-8 OLI sensor from the relationship between the normalized difference chlorophyll index and the floating algal index derived from Sentinel-2A on a coinciding overpass date during the summer CyanoHAB bloom in Utah Lake. This aided in the construction of a time-series phenology of the Utah Lake CyanoHAB event. Spatio-temporal cyanobacterial density maps from both Sentinel-2A and Landsat-8 sensors revealed that the bloom started in the first week of July 2016 (July 3rd, mean cell count: 9163 cells/mL), reached peak in mid-July (July 15th, mean cell count: 108176 cells/mL), and reduced in August (August 24th, mean cell count: 9145 cells/mL). Analysis of physical and meteorological factors suggested a complex interaction between landscape processes (high surface runoff), climatic conditions (high temperature, high rainfall followed by negligible rainfall, stable wind), and water quality (low water level, high Chl-a) which created a supportive environment for triggering these blooms in Utah Lake. This cross satellite-based monitoring methods can be a great tool for regular monitoring and will reduce the budget cost for monitoring and predicting CyanoHABs in large lakes.

Redirecting the Cyanobacterial Bicarbonate Transporters BicA and SbtA to the Chloroplast Envelope: Soluble and Membrane Cargos Need Different Chloroplast Targeting Signals in Plants.

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Vivien eRolland

2016-02-01

Full Text Available Most major crops used for human consumption are C3 plants, which yields are limited by photosynthetic inefficiency. To circumvent this, it has been proposed to implement the cyanobacterial CO2-concentrating mechanism (CCM, principally consisting of bicarbonate transporters and carboxysomes, into plant chloroplasts. As it is currently not possible to recover homoplasmic transplastomic monocots, foreign genes must be introduced in these plants via nuclear transformation. Consequently, it is paramount to ensure that resulting proteins reach the appropriate sub-cellular compartment, which for cyanobacterial transporters BicA and SbtA, is the chloroplast inner-envelope membrane (IEM. At present, targeting signals to redirect large transmembrane proteins from non-chloroplastic organisms to plant chloroplast envelopes are unknown. The goal of this study was to identify such signals, using agrobacteria-mediated transient expression and confocal microscopy to determine the sub-cellular localization of ~37 GFP-tagged chimeras. Initially, fragments of chloroplast proteins known to target soluble cargos to the stroma were tested for their ability to redirect BicA, but they proved ineffective. Next, different N-terminal regions from Arabidopsis IEM transporters were tested. We demonstrated that the N-terminus of AtHP59, AtPLGG1 or AtNTT1 (92-115 amino acids, containing a cleavable chloroplast transit peptide (cTP and a membrane protein leader (MPL, was sufficient to redirect BicA or SbtA to the chloroplast envelope. This constitutes the first evidence that nuclear-encoded transmembrane proteins from non-chloroplastic organisms can be targeted to the envelope of plant chloroplasts; a finding which represents an important advance in chloroplast engineering by opening up the door to further manipulation of the chloroplastic envelope.

Method Development and Monitoring of Cyanotoxins in Water (ACS Central Presentation)

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Increasing occurrence of cyanobacterial harmful algal blooms (HABs) in ambient waters has become a worldwide concern. Numerous cyanotoxins can be produced during HAB events which are toxic to animals and humans. Validated standardized methods that are rugged, selective and sensit...

Risk of combined exposure of birds to cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant.

Science.gov (United States)

Ondracek, Karel; Bandouchova, Hana; Damkova, Veronika; Hilscherova, Klara; Kral, Jiri; Osickova, Jitka; Mlcakova, Veronika; Pohanka, Miroslav; Skochova, Hana; Vitula, Frantisek; Treml, Frantisek; Pikula, Jiri

2012-01-01

The objective of this study was to examine the hypothesis that a combination of cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant can enhance avian toxic effects produced by single exposures only. A total of 48 two-month-old Japanese quails (Coturnix coturnix japonica) with average body weight of 160 g were randomly divided into 8 experimental groups of six birds and sex ratio of 1:1. Experimental groups of control Japanese quails (C) and birds exposed to single and combined sub-lethal doses of paraoxon (P), bromadiolone (B), and microcystins in cyanobacterial biomass (M) included: C, P, P+B, B, B+M, P+M, M, and P+B+M. During the 10-day exposure birds in the respective groups received biomass containing 61.62 µg microcystins daily (i.e. 26.54 µg MC-RR, 7.62 µg MC-YR and 27.39 µg MC-LR), two 250 μg/kg doses of paraoxon, and two 500 mg/kg doses of bromadiolone. Group responses were compared using standard plasma biochemistry and antioxidant/oxidative stress parameters in tissues. While single and double combinations of toxicants induced responses in individual biochemical parameters measured and evaluated using univariate statistical analysis, those in the triple exposure were most extensive. The principal component analysis of antioxidant/oxidative stress parameters (glutathione reductase, lipid peroxidation, and ferric reducing antioxidant power) in tissues (liver, kidney, heart, brain, lungs, gonads, and pectoralis major muscle) clearly separated the triple group (P+B+M) from all single and double exposure groups and the control and indicated thus marked joint effects in the overall pattern of antioxidant/oxidative stress responses of this group. The separation was driven by the modification of the ferric reducing antioxidant power levels in heart and brain and the cardiac lipid peroxidation level, in particular. This experiment contributes to the understanding of the pathogenic mechanisms of combined sub

Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

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Acharya, Celin; Blindauer, Claudia A

2016-02-15

Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

Relationship of cyanobacterial and algal assemblages with vegetation in the high Arctic tundra (West Spitsbergen, Svalbard Archipelago

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Richter Dorota

2015-09-01

Full Text Available The paper presents the results of a study of cyanobacteria and green algae assemblages occurring in various tundra types determined on the basis of mosses and vascular plants and habitat conditions. The research was carried out during summer in the years 2009-2013 on the north sea-coast of Hornsund fjord (West Spitsbergen, Svalbard Archipelago. 58 sites were studied in various tundra types differing in composition of vascular plants, mosses and in trophy and humidity. 141 cyanobacteria and green algae were noted in the research area in total. Cyanobacteria and green algae flora is a significant element of many tundra types and sometimes even dominate there. Despite its importance, it has not been hitherto taken into account in the description and classification of tundra. The aim of the present study was to demonstrate the legitimacy of using phycoflora in supplementing the descriptions of hitherto described tundra and distinguishing new tundra types. Numeric hierarchical-accumulative classification (MVSP 3.1 software methods were used to analyze the cyanobacterial and algal assemblages and their co-relations with particular tundra types. The analysis determined dominant and distinctive species in the communities in concordance with ecologically diverse types of tundra. The results show the importance of these organisms in the composition of the vegetation of tundra types and their role in the ecosystems of this part of the Arctic.

Impacts of Rac- and S-metolachlor on cyanobacterial cell integrity and release of microcystins at different nitrogen levels.

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Wang, Jia; Zhang, Lijuan; Fan, Jiajia; Wen, Yuezhong

2017-08-01

Pesticide residues and nitrogen overload (which caused cyanobacteria blooms) have been two serious environmental concerns. In particular, chiral pesticides with different structures may have various impacts on cyanobacteria. Nitrogen may affect the behavior between pesticides and cyanobacteria (e.g., increase the adverse effects of pesticides on cyanobacteria). This study evaluated the impacts of Rac- and S-metolachlor on the cell integrity and toxin release of Microcystis aeruginosa cells at different nitrogen levels. The results showed that (both of the configurations: Rac-, S-) metolachlor could inhibit M. aeruginosa cell growth under most conditions, and the inhibition rates were increased with the growing concentrations of nitrogen and metolachlor. However, cyanobacterial growth was promoted in 48 h under environmental relevant condition (1 mg/L metolachlor and 0.15 mg/L nitrogen). Therefore, the water authorities should adjust the treatment parameters to remove possible larger numbers of cyaonbacteria under that condition. On the other hand, the inhibition degree of M. aeruginosa cell growth by S-metolachlor treatments was obviously larger than Rac-metolachlor treatments. S-metolachlor also had a stronger ability in compromising M. aeruginosa cells than Rac-metolachlor treatments. Compared to control samples, more extracellular toxins (12%-86% increases) were detected after 5 mg/L S-metolachlor treatment for 72 h at different nitrogen levels, but the variations of extracellular toxins caused by 5 mg/L Rac-metolachlor addition could be neglected. Consequently, higher concentrations of metolachlor in source waters are harmful to humans, but it may prevent cyanobacterial blooms. However, the potential risks (e.g. build-up of extracellular toxins) should be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of a cyanobacterial extract containing-anatoxin-a(s on the cardiac rhythm of Leurolestes circunvagans

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Vania Rodríguez

2012-05-01

Full Text Available This work presents the effects of an anatoxin-a(s-containing extract on a cockroach semi-isolated heart preparation and the results supporting the extract’s biological activity on acetylcholinesterase (purified from ell. The presence of the toxin in cyanobacterial strains Anabaena spiroides (ITEP-024, ITEP-025 and ITEP-026 isolated from the Tapacurá reservoir in Pernambuco, Brazil, was confirmed by means of liquid chromatography coupled to an ion-trap mass spectrometer. The anticholinesterase activity was assessed biochemically by the Ellman test and was confirmed by measuring the cockroach’s heart rate. The concentration of the extract containing the tested anatoxin-a(s (antx-a(s (10, 16 and 100 μg.μL-1 inhibited the eel acetylcholinesterase (AChE by more than 90%. The cockroach cardiac frequency increased by a maximum of about 20% within 29 min after the addition of 2.5x10³ μg of extract containing antxa (s.g-1 bw (n=9, p<0.05. Our results strongly indicate that antx-a(s is capable of exerting biological effects on cockroach, indicating that more research might be conducted to determine its role in the environment, especially on insects.

Fungal parasitism: life cycle, dynamics and impact on cyanobacterial blooms.

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Mélanie Gerphagnon

Full Text Available Many species of phytoplankton are susceptible to parasitism by fungi from the phylum Chytridiomycota (i.e. chytrids. However, few studies have reported the effects of fungal parasites on filamentous cyanobacterial blooms. To investigate the missing components of bloom ecosystems, we examined an entire field bloom of the cyanobacterium Anabaena macrospora for evidence of chytrid infection in a productive freshwater lake, using a high resolution sampling strategy. A. macrospora was infected by two species of the genus Rhizosiphon which have similar life cycles but differed in their infective regimes depending on the cellular niches offered by their host. R. crassum infected both vegetative cells and akinetes while R. akinetum infected only akinetes. A tentative reconstruction of the developmental stages suggested that the life cycle of R. crassum was completed in about 3 days. The infection affected 6% of total cells (and 4% of akinètes, spread over a maximum of 17% of the filaments of cyanobacteria, in which 60% of the cells could be parasitized. Furthermore, chytrids may reduce the length of filaments of Anabaena macrospora significantly by "mechanistic fragmentation" following infection. All these results suggest that chytrid parasitism is one of the driving factors involved in the decline of a cyanobacteria blooms, by direct mortality of parasitized cells and indirectly by the mechanistic fragmentation, which could weaken the resistance of A. macrospora to grazing.

Screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer.

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Singh, Surendra; Datta, Pallavi

2006-01-01

Periodic applications of heavy dosages of herbicides in modern rice-agriculture are a necessary evil for obtaining high crop productivity. Such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. It is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice-field herbicides that can be further improved by mutational techniques to make biofertilizer technology a viable one. Therefore, efforts have been made to screen five dominant diazotrophic cyanobacterial forms e.g. filamentous heterocystous Nostoc punctiforme , Nostoc calcicola , Anabaena variabilis and unicellular Gloeocapsa sp. and Aphanocapsa sp. along with standard laboratory strain Nostoc muscorum ISU against increasing concentrations (0-100 mg l(-1) of four commercial grade common rice-field herbicides i.e. Arozin, Butachlor, Alachlor and 2,4-D under diazotrophic growth conditions. The lethal and IGC(50) concentrations for all four herbicides tested were found highest for A. variabilis as compared to other test cyanobacteria. The lowest reduction in chlorophyll a content, photosynthetic oxygen evolution, and N(2)-fixation was found in A. variabilis as compared to other rice field isolates and standard laboratory strain N. muscorum ISU. On the basis of prolong survival potential and lowest reductions in vital metabolic activities tested at IGC(50) concentration of four herbicides, it is concluded that A. variabilis is the most potent and promising cyanobacterial isolate as compared with other forms. This could be further improved by mutational techniques for exploitation as most potential and viable biofertilizer strain.

Structure-Function, Stability, and Chemical Modification of the Cyanobacterial Cytochrome b6f Complex from Nostoc sp. PCC 7120*

Science.gov (United States)

Baniulis, Danas; Yamashita, Eiki; Whitelegge, Julian P.; Zatsman, Anna I.; Hendrich, Michael P.; Hasan, S. Saif; Ryan, Christopher M.; Cramer, William A.

2009-01-01

The crystal structure of the cyanobacterial cytochrome b6f complex has previously been solved to 3.0-Å resolution using the thermophilic Mastigocladus laminosus whose genome has not been sequenced. Several unicellular cyanobacteria, whose genomes have been sequenced and are tractable for mutagenesis, do not yield b6f complex in an intact dimeric state with significant electron transport activity. The genome of Nostoc sp. PCC 7120 has been sequenced and is closer phylogenetically to M. laminosus than are unicellular cyanobacteria. The amino acid sequences of the large core subunits and four small peripheral subunits of Nostoc are 88 and 80% identical to those in the M. laminosus b6f complex. Purified b6f complex from Nostoc has a stable dimeric structure, eight subunits with masses similar to those of M. laminosus, and comparable electron transport activity. The crystal structure of the native b6f complex, determined to a resolution of 3.0Å (PDB id: 2ZT9), is almost identical to that of M. laminosus. Two unique aspects of the Nostoc complex are: (i) a dominant conformation of heme bp that is rotated 180° about the α- and γ-meso carbon axis relative to the orientation in the M. laminosus complex and (ii) acetylation of the Rieske iron-sulfur protein (PetC) at the N terminus, a post-translational modification unprecedented in cyanobacterial membrane and electron transport proteins, and in polypeptides of cytochrome bc complexes from any source. The high spin electronic character of the unique heme cn is similar to that previously found in the b6f complex from other sources. PMID:19189962

Keynote presentation : SAR systems

NARCIS (Netherlands)

Halsema, D. van; Otten, M.P.G.; Maas, A.P.M.; Bolt, R.J.; Anitori, L.

2011-01-01

Synthetic Aperture Radar (SAR) systems are becoming increasingly important sensors in as well the military environment as in the civilian market. In this keynote presentation an overview will be given over more than 2 decades of SAR system∼ and SAR application development at TNO in the Netherlands.

Cyanobacterial Treatment Options: Permanganate and ...

Science.gov (United States)

This presentation will begin with a brief overview of drinking water treatment options for cyanobacteria and their toxins. The treatment discussion will focus on the impacts of permanganate addition to suspensions of toxin-producing Microcystis aeruginosa, followed by powdered activated carbon (PAC) addition. Results will be presented that show changes in toxin concentrations, chlorophyll-a concentrations and cell membrane integrity. The EPA Small Systems Webinar Presentations allow the dissemination of the latest Agency guidance and research to a large geographically dispersed audience while minimizing taxpayer expense

Conventional Treatment Options for HABs Impacted Waters

Science.gov (United States)

This presentation discusses (1) the removal of cyanobacterial cells through coagulation, flocculation, sedimentation and filtration, (2) the control of cyanobacterial toxins by powdered activated carbon, (3) the control of cyanobacterial toxins by chlorine, UV, ozone, chlorine di...

Cyanobacterial Polyhydroxybutyrate (PHB: Screening, Optimization and Characterization.

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Sabbir Ansari

Full Text Available In modern life petroleum-based plastic has become indispensable due to its frequent use as an easily available and a low cost packaging and moulding material. However, its rapidly growing use is causing aquatic and terrestrial pollution. Under these circumstances, research and development for biodegradable plastic (bioplastics is inevitable. Polyhydroxybutyrate (PHB, a type of microbial polyester that accumulates as a carbon/energy storage material in various microorganisms can be a good alternative. In this study, 23 cyanobacterial strains (15 heterocystous and 8 non-heterocystous were screened for PHB production. The highest PHB (6.44% w/w of dry cells was detected in Nostoc muscorum NCCU- 442 and the lowest in Spirulina platensis NCCU-S5 (0.51% w/w of dry cells, whereas no PHB was found in Cylindrospermum sp., Oscillatoria sp. and Plectonema sp. Presence of PHB granules in Nostoc muscorum NCCU- 442 was confirmed microscopically with Sudan black B and Nile red A staining. Pretreatment of biomass with methanol: acetone: water: dimethylformamide [40: 40: 18: 2 (MAD-I] with 2 h magnetic bar stirring followed by 30 h continuous chloroform soxhlet extraction acted as optimal extraction conditions. Optimized physicochemical conditions viz. 7.5 pH, 30°C temperature, 10:14 h light:dark periods with 0.4% glucose (as additional carbon source, 1.0 gl-1 sodium chloride and phosphorus deficiency yielded 26.37% PHB on 7th day instead of 21st day. Using FTIR, 1H NMR and GC-MS, extracted polymer was identified as PHB. Thermal properties (melting temperature, decomposition temperatures etc. of the extracted polymer were determined by TGA and DSC. Further, the polymer showed good tensile strength and young's modulus with a low extension to break ratio comparable to petrochemical plastic. Biodegradability potential tested as weight loss percentage showed efficient degradation (24.58% of PHB within 60 days by mixed microbial culture in comparison to

Cyanobacterial Polyhydroxybutyrate (PHB): Screening, Optimization and Characterization

Science.gov (United States)

Ansari, Sabbir; Fatma, Tasneem

2016-01-01

In modern life petroleum-based plastic has become indispensable due to its frequent use as an easily available and a low cost packaging and moulding material. However, its rapidly growing use is causing aquatic and terrestrial pollution. Under these circumstances, research and development for biodegradable plastic (bioplastics) is inevitable. Polyhydroxybutyrate (PHB), a type of microbial polyester that accumulates as a carbon/energy storage material in various microorganisms can be a good alternative. In this study, 23 cyanobacterial strains (15 heterocystous and 8 non-heterocystous) were screened for PHB production. The highest PHB (6.44% w/w of dry cells) was detected in Nostoc muscorum NCCU- 442 and the lowest in Spirulina platensis NCCU-S5 (0.51% w/w of dry cells), whereas no PHB was found in Cylindrospermum sp., Oscillatoria sp. and Plectonema sp. Presence of PHB granules in Nostoc muscorum NCCU- 442 was confirmed microscopically with Sudan black B and Nile red A staining. Pretreatment of biomass with methanol: acetone: water: dimethylformamide [40: 40: 18: 2 (MAD-I)] with 2 h magnetic bar stirring followed by 30 h continuous chloroform soxhlet extraction acted as optimal extraction conditions. Optimized physicochemical conditions viz. 7.5 pH, 30°C temperature, 10:14 h light:dark periods with 0.4% glucose (as additional carbon source), 1.0 gl-1 sodium chloride and phosphorus deficiency yielded 26.37% PHB on 7th day instead of 21st day. Using FTIR, 1H NMR and GC-MS, extracted polymer was identified as PHB. Thermal properties (melting temperature, decomposition temperatures etc.) of the extracted polymer were determined by TGA and DSC. Further, the polymer showed good tensile strength and young’s modulus with a low extension to break ratio comparable to petrochemical plastic. Biodegradability potential tested as weight loss percentage showed efficient degradation (24.58%) of PHB within 60 days by mixed microbial culture in comparison to petrochemical plastic

Cyanobacterial Polyhydroxybutyrate (PHB): Screening, Optimization and Characterization.

Science.gov (United States)

Ansari, Sabbir; Fatma, Tasneem

2016-01-01

In modern life petroleum-based plastic has become indispensable due to its frequent use as an easily available and a low cost packaging and moulding material. However, its rapidly growing use is causing aquatic and terrestrial pollution. Under these circumstances, research and development for biodegradable plastic (bioplastics) is inevitable. Polyhydroxybutyrate (PHB), a type of microbial polyester that accumulates as a carbon/energy storage material in various microorganisms can be a good alternative. In this study, 23 cyanobacterial strains (15 heterocystous and 8 non-heterocystous) were screened for PHB production. The highest PHB (6.44% w/w of dry cells) was detected in Nostoc muscorum NCCU- 442 and the lowest in Spirulina platensis NCCU-S5 (0.51% w/w of dry cells), whereas no PHB was found in Cylindrospermum sp., Oscillatoria sp. and Plectonema sp. Presence of PHB granules in Nostoc muscorum NCCU- 442 was confirmed microscopically with Sudan black B and Nile red A staining. Pretreatment of biomass with methanol: acetone: water: dimethylformamide [40: 40: 18: 2 (MAD-I)] with 2 h magnetic bar stirring followed by 30 h continuous chloroform soxhlet extraction acted as optimal extraction conditions. Optimized physicochemical conditions viz. 7.5 pH, 30°C temperature, 10:14 h light:dark periods with 0.4% glucose (as additional carbon source), 1.0 gl-1 sodium chloride and phosphorus deficiency yielded 26.37% PHB on 7th day instead of 21st day. Using FTIR, 1H NMR and GC-MS, extracted polymer was identified as PHB. Thermal properties (melting temperature, decomposition temperatures etc.) of the extracted polymer were determined by TGA and DSC. Further, the polymer showed good tensile strength and young's modulus with a low extension to break ratio comparable to petrochemical plastic. Biodegradability potential tested as weight loss percentage showed efficient degradation (24.58%) of PHB within 60 days by mixed microbial culture in comparison to petrochemical plastic.

The cyanobacterial neurotoxin beta-N-methylamino-L-alanine (BMAA) induces neuronal and behavioral changes in honeybees

Energy Technology Data Exchange (ETDEWEB)

Okle, Oliver, E-mail: oliver.okle@uni-konstanz.de [Human and Environmental Toxicology, University of Konstanz, Jacob-Burckhardt-Strasse 25, 78457 Konstanz (Germany); Rath, Lisa; Galizia, C. Giovanni [Zoology and Neurobiology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz (Germany); Dietrich, Daniel R., E-mail: daniel.dietrich@uni-konstanz.de [Human and Environmental Toxicology, University of Konstanz, Jacob-Burckhardt-Strasse 25, 78457 Konstanz (Germany)

2013-07-01

The cyanobacterially produced neurotoxin beta-N-methylamino-L-alanine (BMAA) is thought to induce amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC)-like symptoms. However, its mechanism of action and its pathway of intoxication are yet unknown. In vivo animal models suitable for investigating the neurotoxic effect of BMAA with applicability to the human are scarce. Hence, we used the honeybee (Apis mellifera) since its nervous system is relatively simple, yet having cognitive capabilities. Bees fed with BMAA-spiked sugar water had an increased mortality rate and a reduced ability to learn odors in a classical conditioning paradigm. Using {sup 14}C-BMAA we demonstrated that BMAA is biologically available to the bee, and is found in the head, thorax and abdomen with little to no excretion. BMAA is also transferred from one bee to the next via trophallaxis resulting in an exposure of the whole beehive. BMAA bath application directly onto the brain leads to an altered Ca{sup 2+} homeostasis and to generation of reactive oxygen species. These behavioral and physiological observations suggest that BMAA may have effects on bee brains similar to those assumed to occur in humans. Therefore the bee could serve as a surrogate model system for investigating the neurological effects of BMAA. - Highlights: • Investigating of neurotoxic effects of BMAA in honeybees • BMAA impairs ALS markers (ROS, Ca{sup 2+}, learning, memory, odor) in bees. • A method for the observation of ROS development in living bees brain was established. • Honeybees are a suitable model to explore neurodegenerative processes. • Neurotoxic BMAA can be spread in bee populations by trophallaxis.

The cyanobacterial neurotoxin beta-N-methylamino-L-alanine (BMAA) induces neuronal and behavioral changes in honeybees

International Nuclear Information System (INIS)

Okle, Oliver; Rath, Lisa; Galizia, C. Giovanni; Dietrich, Daniel R.

2013-01-01

The cyanobacterially produced neurotoxin beta-N-methylamino-L-alanine (BMAA) is thought to induce amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC)-like symptoms. However, its mechanism of action and its pathway of intoxication are yet unknown. In vivo animal models suitable for investigating the neurotoxic effect of BMAA with applicability to the human are scarce. Hence, we used the honeybee (Apis mellifera) since its nervous system is relatively simple, yet having cognitive capabilities. Bees fed with BMAA-spiked sugar water had an increased mortality rate and a reduced ability to learn odors in a classical conditioning paradigm. Using 14 C-BMAA we demonstrated that BMAA is biologically available to the bee, and is found in the head, thorax and abdomen with little to no excretion. BMAA is also transferred from one bee to the next via trophallaxis resulting in an exposure of the whole beehive. BMAA bath application directly onto the brain leads to an altered Ca 2+ homeostasis and to generation of reactive oxygen species. These behavioral and physiological observations suggest that BMAA may have effects on bee brains similar to those assumed to occur in humans. Therefore the bee could serve as a surrogate model system for investigating the neurological effects of BMAA. - Highlights: • Investigating of neurotoxic effects of BMAA in honeybees • BMAA impairs ALS markers (ROS, Ca 2+ , learning, memory, odor) in bees. • A method for the observation of ROS development in living bees brain was established. • Honeybees are a suitable model to explore neurodegenerative processes. • Neurotoxic BMAA can be spread in bee populations by trophallaxis

Community phylogenetic diversity of cyanobacterial mats associated with geothermal springs along a tropical intertidal gradient.

Science.gov (United States)

Jing, Hongmei; Lacap, Donnabella C; Lau, Chui Yim; Pointing, Stephen B

2006-04-01

The 16S rRNA gene-defined bacterial diversity of tropical intertidal geothermal vents subject to varying degrees of seawater inundation was investigated. Shannon-Weaver diversity estimates of clone library-derived sequences revealed that the hottest pools located above the mean high-water mark that did not experience seawater inundation were most diverse, followed by those that were permanently submerged below the mean low-water mark. Pools located in the intertidal were the least biodiverse, and this is attributed to the fluctuating conditions caused by periodic seawater inundation rather than physicochemical conditions per se. Phylogenetic analysis revealed that a ubiquitous Oscillatoria-like phylotype accounted for 83% of clones. Synechococcus-like phylotypes were also encountered at each location, whilst others belonging to the Chroococcales, Oscillatoriales, and other non-phototrophic bacteria occurred only at specific locations along the gradient. All cyanobacterial phylotypes displayed highest phylogenetic affinity to terrestrial thermophilic counterparts rather than marine taxa.

Cyanobacterial Xenobiotics as Evaluated by a Caenorhabditis elegans Neurotoxicity Screening Test

Science.gov (United States)

Ju, Jingjuan; Saul, Nadine; Kochan, Cindy; Putschew, Anke; Pu, Yuepu; Yin, Lihong; Steinberg, Christian E. W.

2014-01-01

In fresh waters cyanobacterial blooms can produce a variety of toxins, such as microcystin variants (MCs) and anatoxin-a (ANA). ANA is a well-known neurotoxin, whereas MCs are hepatotoxic and, to a lesser degree, also neurotoxic. Neurotoxicity applies especially to invertebrates lacking livers. Current standardized neurotoxicity screening methods use rats or mice. However, in order to minimize vertebrate animal experiments as well as experimental time and effort, many investigators have proposed the nematode Caenorhabditis elegans as an appropriate invertebrate model. Therefore, four known neurotoxic compounds (positive compounds: chlorpyrifos, abamectin, atropine, and acrylamide) were chosen to verify the expected impacts on autonomic (locomotion, feeding, defecation) and sensory (thermal, chemical, and mechanical sensory perception) functions in C. elegans. This study is another step towards successfully establishing C. elegans as an alternative neurotoxicity model. By using this protocol, anatoxin-a adversely affected locomotive behavior and pharyngeal pumping frequency and, most strongly, chemotactic and thermotactic behavior, whereas MC-LR impacted locomotion, pumping, and mechanical behavior, but not chemical sensory behavior. Environmental samples can also be screened in this simple and fast way for neurotoxic characteristics. The filtrate of a Microcystis aeruginosa culture, known for its hepatotoxicity, also displayed mild neurotoxicity (modulated short-term thermotaxis). These results show the suitability of this assay for environmental cyanotoxin-containing samples. PMID:24776722

How Cyanobacterial Distributions Reveal Flow and Irradiance Conditions of Photosynthetic Biofilm Formation

Science.gov (United States)

Prufert-Bebout, Lee

2001-01-01

Microbial life on Earth is enormously abundant at sediment-water interfaces. The fossil record in fact contains abundant evidence of the preservation of life on such surfaces. It is therefore critical to our interpretation of early Earth history, and potentially to history of life on other planets, to be able to recognize life forms at these interfaces. On Earth this life often occurs as organized structures of microbes and their extracellular exudates known as biofilms. When such biofilms occur in areas receiving sunlight photosynthetic biofilms are the dominant form in natural ecosystems due to selective advantage inherent in their ability to utilize solar energy. Cyanobacteria are the dominant phototrophic microbes in most modern and ancient photosynthetic biofilms, microbial mats and stromatolites. Due to their long (3.5 billion year) evolutionary history, this group has extensively diversified resulting in an enormous array of morphologies and physiological abilities. This enormous diversity and specialization results in very specific selection for a particular cyanobacterium in each available photosynthetic niche. Furthermore these organisms can alter their spatial orientation, cell morphology, pigmentation and associations with heterotrophic organisms in order to fine tune their optimization to a given micro-niche. These adaptations can be detected, and if adequate knowledge of the interaction between environmental conditions and organism response is available, the detectable organism response can be used to infer the environmental conditions causing that response. This presentation will detail two specific examples which illustrate this point. Light and water are essential to photosynthesis in cyanobacteria and these organisms have specific detectable behavioral responses to these parameters. We will present cyanobacterial responses to quantified flow and irradiance to demonstrate the interpretative power of distribution and orientation information. This

Removal of cyanobacterial toxins by sediment passage

Science.gov (United States)

Gruetzmacher, G.; Boettcher, G.; Chorus, I.; Bartel, H.

2003-04-01

Cyanbacterial toxins ("Cyanotoxins") comprise a wide range of toxic substances produced by cyanobacteria ("blue-green algae"). Cyanobacteria occur in surface water word wide and can be found in high concentrations during so-called algal blooms when conditions are favourable (e.g. high nutrient levels, high temperatures). Some cyanobacteria produce hepato- or neurotoxins, of which the hepatotoxic microcystins are the most common in Germany. The WHO guideline value for drinking water was set at 1 μg/L. However, maximum concentrations in surface water can reach 25 mg/L, so that a secure method for toxin elimination has to be found when this water is used as source water for drinking water production. In order to assess if cyanotoxins can be removed by sediment passage the German Federal Environmental Agency (UBA) conducted laboratory- and field scale experiments as well as observations on bank filtration field sites. Laboratory experiments (batch- and column experiments for adsorption and degradation parameters) were conducted in order to vary a multitude of experimental conditions. These experiments were followed by field scale experiments on the UBA's experimental field in Berlin. This plant offers the unique possibility to conduct experiments on the behaviour of various agents - such as harmful substances - during infiltration and bank filtration under well-defined conditions on a field scale, and without releasing these substances to the environment. Finally the development of microcystin concentrations was observed between infiltrating surface water and a drinking water well along a transsecte of observation wells. The results obtained show that infiltration and bank filtration normally seem to be secure treatment methods for source water contaminated by microcystins. However, elimination was shown to be difficult under the following circumstances: - dying cyanobacterial population due to insufficient light and / or nutrients, low temperatures or application of

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

A mat structure with linearly arranged microbial filaments and hollow, cell-based coccoid cyanobacterial mat are present. Nodules contain abundant carbonate fluorapatite, followed by minor calcite, quartz and feldspar. The P2O5 content of the phosphorites ranges from 18 to 26%. The CaO/P2O5, Sr and F contents are ...

Construction Tele-Robotics System with AR Presentation

International Nuclear Information System (INIS)

Ootsubo, K; Kawamura, T; Yamada, H

2013-01-01

Tele-Robotics system using bilateral control is an effective tool for task in disaster scenes, and also in extreme environments. The conventional systems are equipped with a few color video cameras captures view of the task field, and their video images are sent to the operator via some network. Usually, the images are captured only from some fixed angles. So the operator cannot obtain intuitively 3D-sense of the task field. In our previous study, we proposed a construction tele-robotics system based on VR presentation. The operator intuits the geometrical states of the robot presented by CG, but the information of the surrounding environment is not included like a video image. So we thought that the task efficiency could be improved by appending the CG image to the video image. In this study, we developed a new presentation system based on augmented reality (AR). In this system, the CG image, which represents 3D geometric information for the task, is overlaid on the video image. In this study, we confirmed the effectiveness of the system experimentally. Additionally, we verified its usefulness to reduction of the communication delay associated with a tele-robotics system.

Resolving the contribution of the uncoupled phycobilisomes to cyanobacterial pulse-amplitude modulated (PAM) fluorometry signals.

Science.gov (United States)

Acuña, Alonso M; Snellenburg, Joris J; Gwizdala, Michal; Kirilovsky, Diana; van Grondelle, Rienk; van Stokkum, Ivo H M

2016-01-01

Pulse-amplitude modulated (PAM) fluorometry is extensively used to characterize photosynthetic organisms on the slow time-scale (1-1000 s). The saturation pulse method allows determination of the quantum yields of maximal (F(M)) and minimal fluorescence (F(0)), parameters related to the activity of the photosynthetic apparatus. Also, when the sample undergoes a certain light treatment during the measurement, the fluorescence quantum yields of the unquenched and the quenched states can be determined. In the case of cyanobacteria, however, the recorded fluorescence does not exclusively stem from the chlorophyll a in photosystem II (PSII). The phycobilins, the pigments of the cyanobacterial light-harvesting complexes, the phycobilisomes (PB), also contribute to the PAM signal, and therefore, F(0) and F(M) are no longer related to PSII only. We present a functional model that takes into account the presence of several fluorescent species whose concentrations can be resolved provided their fluorescence quantum yields are known. Data analysis of PAM measurements on in vivo cells of our model organism Synechocystis PCC6803 is discussed. Three different components are found necessary to fit the data: uncoupled PB (PB(free)), PB-PSII complexes, and free PSI. The free PSII contribution was negligible. The PB(free) contribution substantially increased in the mutants that lack the core terminal emitter subunits allophycocyanin D or allophycocyanin F. A positive correlation was found between the amount of PB(free) and the rate constants describing the binding of the activated orange carotenoid protein to PB, responsible for non-photochemical quenching.

Database Systems - Present and Future

Directory of Open Access Journals (Sweden)

2009-01-01

Full Text Available The database systems have nowadays an increasingly important role in the knowledge-based society, in which computers have penetrated all fields of activity and the Internet tends to develop worldwide. In the current informatics context, the development of the applications with databases is the work of the specialists. Using databases, reach a database from various applications, and also some of related concepts, have become accessible to all categories of IT users. This paper aims to summarize the curricular area regarding the fundamental database systems issues, which are necessary in order to train specialists in economic informatics higher education. The database systems integrate and interfere with several informatics technologies and therefore are more difficult to understand and use. Thus, students should know already a set of minimum, mandatory concepts and their practical implementation: computer systems, programming techniques, programming languages, data structures. The article also presents the actual trends in the evolution of the database systems, in the context of economic informatics.

Spatial patterns of cyanobacterial mat growth on sand ripples

Science.gov (United States)

Mariotti, G.; Klepac-Ceraj, V.; Perron, J. T.; Bosak, T.

2016-02-01

Photosynthetic microbial mats produce organic matter, cycle nutrients, bind pollutants and stabilize sediment in sandy marine environments. Here, we investigate the influence of bedforms and wave motion on the growth rate, composition and spatial variability of microbial mats by growing cyanobacterial mats on a rippled bed of carbonate sand in a wave tank. The tank was forced with an oscillatory flow with velocities below the threshold for sediment motion yet able to induce a porewater flow within the sediment. Different spatial patterns developed in mats depending on the initial biochemistry of the water medium. When growing in a medium rich in nitrogen, phosphorous and micronutrients, mats grew faster on ripple troughs than on ripple crests. After two months, mats covered the bed surface uniformly, and the microbial communities on the crests and in the troughs had similar compositions. Differences in bed shear stress and nutrient availability between crests and troughs were not able to explain the faster growth in the troughs. We hypothesize that this growth pattern is due to a "strainer" effect, i.e. the suspended bacteria from the inoculum were preferentially delivered to troughs by the wave-induced porewater flow. In the experiments initiated in a medium previously used up by a microbial mat and thus depleted in nutrients, mats grew preferentially on the ripple crests. This spatial pattern persisted for nearly two years, and the microbial composition on troughs and crests was different. We attribute this pattern to the upwelling of porewater in the crests, which increased the delivery of nutrients from sediment to the cyanobacteria on the bed surface. Thus, the macroscopic patterns formed by photosynthetic microbial mats on sand ripples may be used to infer whether mats are nutrient-limited and whether they are recently colonized or older than a month.

Kocuria polaris sp. nov., an orange-pigmented psychrophilic bacterium isolated from an Antarctic cyanobacterial mat sample.

Science.gov (United States)

Reddy, Gundlapally S N; Prakash, Jogadhenu S S; Prabahar, Vadivel; Matsumoto, Genki I; Stackebrandt, Erko; Shivaji, Sisinthy

2003-01-01

Strain CMS 76orT, an orange-pigmented bacterium, was isolated from a cyanobacterial mat sample from a pond located in McMurdo Dry Valley, Antarctica. On the basis of chemotaxonomic and phylogenetic properties, strain CMS 76orT was identified as a member of the genus Kocuria. It exhibited a 16S rDNA similarity of 99.8% and DNA-DNA similarity of 71% with Kocuria rosea (ATCC 186T). Phenotypic traits confirmed that strain CMS 78orT and K. rosea were well differentiated. Furthermore, strain CMS 76orT could be differentiated from the other reported species of Kocuria, namely Kocuria kristinae (ATCC 27570T), Kocuria varians (ATCC 15306T), Kocuria rhizophila (DSM 11926T) and Kocuria palustris (DSM 11025T), on the basis of a number of phenotypic features. Therefore, it is proposed that strain CMS 76orT (= MTCC 3702T = DSM 14382T) be assigned to a novel species of the genus Kocuria, as Kocuria polaris.

Minimal tool set for a prokaryotic circadian clock.

Science.gov (United States)

Schmelling, Nicolas M; Lehmann, Robert; Chaudhury, Paushali; Beck, Christian; Albers, Sonja-Verena; Axmann, Ilka M; Wiegard, Anika

2017-07-21

Circadian clocks are found in organisms of almost all domains including photosynthetic Cyanobacteria, whereby large diversity exists within the protein components involved. In the model cyanobacterium Synechococcus elongatus PCC 7942 circadian rhythms are driven by a unique KaiABC protein clock, which is embedded in a network of input and output factors. Homologous proteins to the KaiABC clock have been observed in Bacteria and Archaea, where evidence for circadian behavior in these domains is accumulating. However, interaction and function of non-cyanobacterial Kai-proteins as well as homologous input and output components remain mainly unclear. Using a universal BLAST analyses, we identified putative KaiC-based timing systems in organisms outside as well as variations within Cyanobacteria. A systematic analyses of publicly available microarray data elucidated interesting variations in circadian gene expression between different cyanobacterial strains, which might be correlated to the diversity of genome encoded clock components. Based on statistical analyses of co-occurrences of the clock components homologous to Synechococcus elongatus PCC 7942, we propose putative networks of reduced and fully functional clock systems. Further, we studied KaiC sequence conservation to determine functionally important regions of diverged KaiC homologs. Biochemical characterization of exemplary cyanobacterial KaiC proteins as well as homologs from two thermophilic Archaea demonstrated that kinase activity is always present. However, a KaiA-mediated phosphorylation is only detectable in KaiC1 orthologs. Our analysis of 11,264 genomes clearly demonstrates that components of the Synechococcus elongatus PCC 7942 circadian clock are present in Bacteria and Archaea. However, all components are less abundant in other organisms than Cyanobacteria and KaiA, Pex, LdpA, and CdpA are only present in the latter. Thus, only reduced KaiBC-based or even simpler, solely KaiC-based timing systems

Mitigating cyanobacterial harmful algal blooms in aquatic ecosystems impacted by climate change and anthropogenic nutrients.

Science.gov (United States)

Paerl, Hans W; Gardner, Wayne S; Havens, Karl E; Joyner, Alan R; McCarthy, Mark J; Newell, Silvia E; Qin, Boqiang; Scott, J Thad

2016-04-01

Mitigating the global expansion of cyanobacterial harmful blooms (CyanoHABs) is a major challenge facing researchers and resource managers. A variety of traditional (e.g., nutrient load reduction) and experimental (e.g., artificial mixing and flushing, omnivorous fish removal) approaches have been used to reduce bloom occurrences. Managers now face the additional effects of climate change on watershed hydrologic and nutrient loading dynamics, lake and estuary temperature, mixing regime, internal nutrient dynamics, and other factors. Those changes favor CyanoHABs over other phytoplankton and could influence the efficacy of control measures. Virtually all mitigation strategies are influenced by climate changes, which may require setting new nutrient input reduction targets and establishing nutrient-bloom thresholds for impacted waters. Physical-forcing mitigation techniques, such as flushing and artificial mixing, will need adjustments to deal with the ramifications of climate change. Here, we examine the suite of current mitigation strategies and the potential options for adapting and optimizing them in a world facing increasing human population pressure and climate change. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of cyanobacterial-driven pH increases on sediment nutrient fluxes and coupled nitrification-denitrification in a shallow fresh water estuary

Directory of Open Access Journals (Sweden)

Y. Gao

2012-07-01

Full Text Available Summer cyanobacterial blooms caused an elevation in pH (9 to ~10.5 that lasted for weeks in the shallow and tidal-fresh region of the Sassafras River, a tributary of Chesapeake Bay (USA. Elevated pH promoted desorption of sedimentary inorganic phosphorus and facilitated conversion of ammonium (NH₄⁺ to ammonia (NH₃. In this study, we investigated pH effects on exchangeable NH₄⁺ desorption, pore water diffusion and the flux rates of NH₄⁺, soluble reactive phosphorus (SRP and nitrate (NO₃⁻, nitrification, denitrification, and oxygen consumption. Elevated pH enhanced desorption of exchangeable NH₄⁺ through NH₃ formation from both pore water and adsorbed NH₄⁺ pools. Progressive penetration of high pH from the overlying water into sediment promoted the mobility of SRP and the release of total ammonium (NH₄⁺ and NH₃ into the pore water. At elevated pH levels, high sediment-water effluxes of SRP and total ammonium were associated with reduction of nitrification, denitrification and oxygen consumption rates. Alkaline pH and the toxicity of NH₃ may inhibit nitrification in the thin aerobic zone, simultaneously constraining coupled nitrification–denitrification with limited NO₃⁻ supply and high pH penetration into the anaerobic zone. Geochemical feedbacks to pH elevation, such as enhancement of dissolved nutrient effluxes and reduction in N₂ loss via denitrification, may enhance the persistence of cyanobacterial blooms in shallow water ecosystems.

The biodegradation of layered silicates under the influence of cyanobacterial-actinomycetes associations

Science.gov (United States)

Ivanova, Ekaterina

2013-04-01

The weathering of sheet silicates is well known to be related to local and global geochemical cycles. Content and composition of clay minerals in soil determine the sorption properties of the soil horizons, water-holding capacity of the soil, stickiness, plasticity, etc. Microorganisms have a diverse range of mechanisms of minerals' structure transformation (acid- and alkali formation, biosorption, complexing, etc). One of the methods is an ability of exopolysaccharide-formation, in particular the formation of mucus, common to many bacteria, including cyanobacteria. Mucous covers cyanobacteria are the specific econiches for other bacteria, including actinomycetes. The objective was to analyze the structural changes of clay minerals under the influence of the cyanobacterial-actinomycetes associative growth. The objects of the study were: 1) the experimental symbiotic association, consisting of free-living heterocyst-formative cyanobacterium Anabaena variabilis Kutz. ATCC 294132 and actinomycete Streptomyces cyaneofuscatus FR837630, 2) rock samples obtained from the Museum of the Soil Science Department of the Lomonosov Moscow State University: kaolinite, consisting of kaolin (96%) Al4 (OH) 8 [Si4O10]; mixed with hydromica, chlorite and quartz; vermiculite, consisting of vermiculite (Ca, Mg, ...)*(Mg, Fe)3(OH)2[(Si, Al)4O10]*4H2O and trioctahedral mica (biotite). The mineralogical compositions of the rocks were determined by the universal X-ray Diffractometer Carl Zeiss Yena. The operationg regime was kept constant (30 kv, 40 mA). The cultivation of the association of actinomycete S. cyanoefuscatus and cyanobacterium A. variabilis caused a reduction in the intensity of kaolinite and hydromica reflexes. However, since both (mica and kaolinite) components have a rigid structure, the significant structural transformation of the minerals was not revealed. Another pattern was observed in the experiment, where the rock sample of vermiculite was used as the mineral

Can environmental conditions trigger cyanobacterial surfaces and following carbonate formation: implication for biomineralization and biotechnology

Science.gov (United States)

Paulo, C.; Dittrich, M.; Zhu, T.

2015-12-01

In this presentation we will give an overview what kind of the factors may trigger carbonate formations at the cell surfaces under a variety of environmental conditions. As examples, we will present the results from our recent studies on formation of calcium carbonates, dolomites and bio-cements. The extracellular polymeric substances (EPS) in the Synechococcuscell envelope are recognized key players in the nucleation of carbonates in marine and freshwater environments. Yet, little is known about a nutrient contents control over the molecular composition of Synechococcus cell envelope, and consequently, biomineralization. In the first study, we investigated how a variation of the phosphorus (P) in the growth media can lead to changes in the surface reactivity of the cells and impact their ability to form carbonates. The objective of the second study is to gain insights into the spatial distribution of cyanobacterial EPS and dolomite from different sediment layers of Khor Al-Adaid sabkha (Qatar). Here, we characterized microbial mats on molecular level in respect of organic and inorganic components using in-situ 2D Raman spectroscopy and Atomic Force Microscopy (AFM) were used. Additionally, 2D chemical maps of sediment layers documented spectral characterizations of minerals and organic matter of microbial origins at high spatial resolution. Finally, we will show the results from the experiments with auto-phototrophic cyanobacteria Gloeocapsa PCC73106, which habitat on the monument surfaces, towards its application for bio-concrete, a product of microbial carbonate precipitation. We studied the biomineralization in biofilm forming Gloeocapsa PCC73106 on the concrete surface as a pre-requirement for microbial carbonate precipitation. Biomineralization on the concrete surface by live cells and killed cells were compared with that under the abiotic condition. Our experiments allow us to conclude that environmental conditions play a significant role in the control of

Organic matter degradation drives benthic cyanobacterial mat abundance on Caribbean coral reefs.

Science.gov (United States)

Brocke, Hannah J; Polerecky, Lubos; de Beer, Dirk; Weber, Miriam; Claudet, Joachim; Nugues, Maggy M

2015-01-01

Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised areas. Reefs with high BCM abundance were also characterised by high benthic cover of macroalgae and low cover of corals. Nutrient concentrations in the water-column were consistently low, but markedly increased just above substrata (both sandy and hard) covered with BCMs. This was true for sites with both high and low BCM coverage, suggesting that BCM growth is stimulated by a localised, substrate-linked release of nutrients from the microbial degradation of organic matter. This hypothesis was supported by a higher organic content in sediments on reefs with high BCM coverage, and by an in situ experiment which showed that BCMs grew within days on sediments enriched with organic matter (Spirulina). We propose that nutrient runoff from urbanised areas stimulates phototrophic blooms and enhances organic matter concentrations on the reef. This organic matter is transported by currents and settles on the seabed at sites with low hydrodynamics. Subsequently, nutrients released from the organic matter degradation fuel the growth of BCMs. Improved management of nutrients generated on land should lower organic loading of sediments and other benthos (e.g. turf and macroalgae) to reduce BCM proliferation on coral reefs.

Aerobic and anaerobic nitrogen transformation processes in N2-fixing cyanobacterial aggregates.

Science.gov (United States)

Klawonn, Isabell; Bonaglia, Stefano; Brüchert, Volker; Ploug, Helle

2015-06-01

Colonies of N(2)-fixing cyanobacteria are key players in supplying new nitrogen to the ocean, but the biological fate of this fixed nitrogen remains poorly constrained. Here, we report on aerobic and anaerobic microbial nitrogen transformation processes that co-occur within millimetre-sized cyanobacterial aggregates (Nodularia spumigena) collected in aerated surface waters in the Baltic Sea. Microelectrode profiles showed steep oxygen gradients inside the aggregates and the potential for nitrous oxide production in the aggregates' anoxic centres. (15)N-isotope labelling experiments and nutrient analyses revealed that N(2) fixation, ammonification, nitrification, nitrate reduction to ammonium, denitrification and possibly anaerobic ammonium oxidation (anammox) can co-occur within these consortia. Thus, N. spumigena aggregates are potential sites of nitrogen gain, recycling and loss. Rates of nitrate reduction to ammonium and N(2) were limited by low internal nitrification rates and low concentrations of nitrate in the ambient water. Presumably, patterns of N-transformation processes similar to those observed in this study arise also in other phytoplankton colonies, marine snow and fecal pellets. Anoxic microniches, as a pre-condition for anaerobic nitrogen transformations, may occur within large aggregates (⩾1 mm) even when suspended in fully oxygenated waters, whereas anoxia in small aggregates (1.5 μM), O(2)-depleted water layers, for example, in the chemocline of the Baltic Sea or the oceanic mesopelagic zone, aggregates may promote N-recycling and -loss processes.

Systemic calciphylaxis presenting as a painful, proximal myopathy.

OpenAIRE

Edelstein, C. L.; Wickham, M. K.; Kirby, P. A.

1992-01-01

A renal transplant patient who presented with a painful, proximal myopathy due to systemic calciphylaxis is described. The myopathy preceded the characteristic skin and soft tissue necrosis. Systemic calciphylaxis should be considered in a dialysis or a renal transplant patient presenting with a painful proximal myopathy even in the absence of necrotic skin lesions.

Clinical presentation in patients with systemic sclerosis

International Nuclear Information System (INIS)

Silvarino, R.; Rebella, M.; Alonso, J.; Cairoli, E.

2009-01-01

Introduction: systemic sclerosis is an autoimmune disease characterized by endothelial damage, and skin, vessel and internal organ fibrosis and inflammation. There are differences in terms of frequency, severity and prognosis for the different ethnic groups, what reinforces the importance of the study in each geographical region with the purpose of enabling early diagnosis of its incipient symptoms.Methods: we conducted a descriptive and retrospective study form March 2006 through March 2008, including patients with a final diagnosis of systemic sclerosis, who are treated at the Systemic Autoimmune Diseases Unit at the Clinicas Hospital. Results: 31 women were included in the study, average follow-up of patients was 39.2 months, and average age at the time of diagnosis was 47.6 years. Eleven patients (35,5) presented diffuse disease and 20 (64.5) of them evidenced limited disease. Thirty patients presented Raynaud's phenomenon. In 92 of cases capilaroscopy showed a sclerodermiform pattern. In terms of the respiratory system, we found interstitial pathology in 25 of cases, pulmonary arterial hypertension in 22.2 and are restrictive pattern in respiratory function studies in 35.5. Also, 67.7 presented digestive manifestations and 9.6 developed sclerodermic renal crisis. We found anti-nuclear antibodies (ANA) in 29 out of 31 patients (93,5) patients; 16 presented anticentromere antibodies and five anti-topoisomerasa-I antibodies. The four patients (12.9)who died during follow-up presented common elements such as diffuse sclerosis, digital ulcers and severe respiratory compromise. Conclusions: the clinical and immune characteristics found in our study were similar to those described in other series. Should there be no specific treatment, it is essential to perform regular assessment of visceral impact in order to control and delay complications which result in high morbimortality rates. (author) [es

Biotechnological Screening of Microalgal and Cyanobacterial Strains for Biogas Production and Antibacterial and Antifungal Effects

Directory of Open Access Journals (Sweden)

Opayi Mudimu

2014-05-01

Full Text Available Microalgae and cyanobacteria represent a valuable natural resource for the generation of a large variety of chemical substances that are of interest for medical research, can be used as additives in cosmetics and food production, or as an energy source in biogas plants. The variety of potential agents and the use of microalgae and cyanobacteria biomass for the production of these substances are little investigated and not exploited for the market. Due to the enormous biodiversity of microalgae and cyanobacteria, they hold great promise for novel products. In this study, we investigated a large number of microalgal and cyanobacterial strains from the Culture Collection of Algae at Göttingen University (SAG with regard to their biomass and biogas production, as well antibacterial and antifungal effects. Our results demonstrated that microalgae and cyanobacteria are able to generate a large number of economically-interesting substances in different quantities dependent on strain type. The distribution and quantity of some of these components were found to reflect phylogenetic relationships at the level of classes. In addition, between closely related species and even among multiple isolates of the same species, the productivity may be rather variable.

Cyanobacterial blooms in stratified and destratified eutrophic reservoirs in semi-arid region of Brazil.

Science.gov (United States)

Dantas, Enio W; Moura, Ariadne N; Bittencourt-Oliveira, Maria do Carmo

2011-12-01

This study investigated the dynamics of cyanobacteria in two deep, eutrophic reservoirs in a semi-arid region of Brazil during periods of stratification and destratification. Four collections were carried out at each reservoir at two depths at three-month intervals. The following abiotic variables were analyzed: water temperature, dissolved oxygen, pH, turbidity, water transparency, total phosphorus, total dissolved phosphorus, orthophosphate and total nitrogen. Phytoplankton density was quantified for the determination of the biomass of cyanobacteria. The data were analyzed using CCA. Higher mean phytoplankton biomass values (29.8 mm(3).L(-1)) occurred in the period of thermal stratification. A greater similarity in the phytoplankton communities also occurred in this period and was related to the development of cyanobacteria, mainly Cylindrospermopsis raciborskii (>3.9 mm(3).L(-1)). During the period of thermal destratification, this species co-dominated the environment with Planktothrix agardhii, Geitlerinema amphibium, Microcystis aeruginosa and Merismopedia tenuissima, as well as with diatoms and phytoflagellates. Environmental instability and competition among algae hindered the establishment of blooms more during the mixture period than during the stratification period. Thermal changes in the water column caused by climatologic events altered other physiochemical conditions of the water, leading to changes in the composition and biomass of the cyanobacterial community in tropical reservoirs.

Toxicity at the Edge of Life: A Review on Cyanobacterial Toxins from Extreme Environments.

Science.gov (United States)

Cirés, Samuel; Casero, María Cristina; Quesada, Antonio

2017-07-24

Cyanotoxins are secondary metabolites produced by cyanobacteria, of varied chemical nature and toxic effects. Although cyanobacteria thrive in all kinds of ecosystems on Earth even under very harsh conditions, current knowledge on cyanotoxin distribution is almost restricted to freshwaters from temperate latitudes. In this review, we bring to the forefront the presence of cyanotoxins in extreme environments. Cyanotoxins have been reported especially in polar deserts (both from the Arctic and Antarctica) and alkaline lakes, but also in hot deserts, hypersaline environments, and hot springs. Cyanotoxins detected in these ecosystems include neurotoxins-anatoxin-a, anatoxin-a (S), paralytic shellfish toxins, β-methylaminopropionic acid, N -(2-aminoethyl) glycine and 2,4-diaminobutyric acid- and hepatotoxins -cylindrospermopsins, microcystins and nodularins-with microcystins being the most frequently reported. Toxin production there has been linked to at least eleven cyanobacterial genera yet only three of these ( Arthrospira , Synechococcus and Oscillatoria ) have been confirmed as producers in culture. Beyond a comprehensive analysis of cyanotoxin presence in each of the extreme environments, this review also identifies the main knowledge gaps to overcome (e.g., scarcity of isolates and -omics data, among others) toward an initial assessment of ecological and human health risks in these amazing ecosystems developing at the very edge of life.

Central nervous system tuberculomata presenting as internuclear ...

African Journals Online (AJOL)

Central nervous system (CNS) tuberculoma can have variable presentation depending upon the site and number of tuberculomata. We are reporting a rare case of a 15 years old girl who presented to our hospital with binocular diplopia on right gaze. Clinical examination revealed left sided internuclear ophthalmoplegia ...

Simultaneous elimination of cyanotoxins and PCBs via mechanical collection of cyanobacterial blooms: An application of "green-bioadsorption concept".

Science.gov (United States)

Chen, Wei; Jia, Yunlu; Liu, Anyue; Zhou, Qichao; Song, Lirong

2017-07-01

In this study, the distribution, transfer and fate of both polychlorinated biphenyls (PCBs) and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes. Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms. Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation. Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns, and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater. According to these findings, a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed. In the practice of mechanical collections of bloom biomass from Lake Taihu, cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory. Copyright © 2016. Published by Elsevier B.V.

Removal of cyanobacteria and cyanotoxins through drinking water treatment-full-scale studies?

Science.gov (United States)

This presentation covers the control of intact cyanobacterial cells through particulate removal processes such as coagulation, sedimentation and filtration. The control of cyanobacterial toxins through oxidation and adsorption processes including, but not limited to, chlorine, oz...

Unusual presentation of childhood Systemic Lupus Erythematosus

Science.gov (United States)

Kumar, Sathish; Agarwal, Indira

2007-01-01

Bullous systemic lupus erythematosus is a rare blistering condition with a distinctive combination of clinical, histological and immunopathologic features that together constitute a unique bullous disease phenotype. It is often associated with autoimmunity to type VII collagen. Here we report a child who presented with bullous systemic lupus erythematosus. Rapid resolution of the blisters occurred following treatment with dapsone. PMID:18028550

An evolutionary fitness enhancement conferred by the circadian system in cyanobacteria

International Nuclear Information System (INIS)

Ma, Peijun; Woelfle, Mark A.; Johnson, Carl Hirschie

2013-01-01

Circadian clocks are found in a wide variety of organisms from cyanobacteria to mammals. Many believe that the circadian clock system evolved as an adaption to the daily cycles in light and temperature driven by the rotation of the earth. Studies on the cyanobacterium, Synechococcus elongatus PCC 7942, have confirmed that the circadian clock in resonance with environmental cycles confers an adaptive advantage to cyanobacterial strains with different clock properties when grown in competition under light–dark cycles. The results thus far suggest that in a cyclic environment, the cyanobacterial strains whose free running periods are closest to the environmental period are the most fit and the strains lacking a functional circadian clock are at a competitive disadvantage relative to strains with a functional clock. In contrast, the circadian system provides little or no advantage to cyanobacteria grown in competition in constant light. To explain the potential mechanism of this clock-mediated enhancement in fitness in cyanobacteria, several models have been proposed; these include the limiting resource model, the diffusible inhibitor model and the cell-to-cell communication model. None of these models have been excluded by the currently available experimental data and the mechanistic basis of clock-mediated fitness enhancement remains elusive

Growth Characterization and Optimization of Cyanobacterial Isolates from the Arabian Gulf

KAUST Repository

Siller Rodriguez, Luis F.

2013-12-01

Photoautotrophic organisms have been highlighted as carbon capture and conversion platforms for sustainable production of agricultural and chemicals in KSA. Previously two cyanobacterial strains, Geitlerinema spp. CT7801 and CT7802, were isolated from an industrial brine outfall site in the Eastern Province of the Kingdom of Saudi Arabia. Initial characterization of their growth characteristics showed growth at high temperature (38 ºC) and high salinity ( > 60 PSU), making them potentially good candidates for industrial applications. In this study, quantitative growth assays were performed using standardized methods developed for the analysis of Red Sea photosynthetic microorganisms supported by microscopic observations, optimal growth media preference assays, CO2 concentration effect, photoperiod effect, mixotrophic and heterotrophic growth tests. Data was recorded for absorbance (600 and 750 nm wave lenght), dry cell weight (DCW), colorimetric observations, and chlorophyll a content. Both CT7801 and CT7802 exhibited a clear preference for Walne\\'s Red Sea medium. An analysis on media composition highlights B and Fe as growth enhancers, as well as a base requirement of seawater. Tests on the effect of supplied concentration of CO2 showed that air enhanced with 1 % v/v CO2 allows approximately 2-fold increase in DCW for Geitlerinema spp. CT7802. Photoperiod tests showed that continuous light is disadvantageous for phototrophic growth of Geitlerinema spp. CT7801 and CT7802. Results for mixotrophic and heterotrophic growth of Geitlerinema spp. CT7801 and CT7802 revealed their ability to metabolize glycerol. Analysis on the complete genome of CT7802 identified three key enzymes, glycerol kinase, glycerol-3-phosphate dehydrogenase and triosephosphate isomerase, which may catalyze the glycerol metabolic pathway in the strain. Utilization of glycerol, a residue of the biodiesel industry, might provide a sustainable alternative for growth of Geitlerinema sp. CT7802.

Past, Present and Future of Linac 2 Vacuum System

CERN Document Server

Mahner, E

2011-01-01

This note aims to review the past, present, and future operation of CERN's Linac 2 vacuum system. The machine vacuum system layout with its major components is summarized. Operational problems arising in 2006 yielded to a leak test campaign of the whole machine, which detected a new, major leak on tank 3. Details about the mitigation of this leak are described as well as additional diagnostics installed during shutdown 2006/07. The pressure evolution of the most critical vacuum sector is analyzed. A statistics of vacuum system faults observed since 2000 is presented and compared with other systems. Finally, a perspective for the vacuum system operation until 2017/18 is outlined.

Test Rig Design and Presentation for a Hydraulic Yaw System

DEFF Research Database (Denmark)

Stubkier, Søren; Pedersen, Henrik C.; Andersen, Torben Ole

2013-01-01

The design and development of a hydraulic yaw system for multi MWturbines is presented and the concept explained. As part of the development of the new concept a full scale test rig for a 5 MW wind turbine has been designed and constructed. The test rig is presented along with its unique design...... features. The design process is outlined to give insight in the design criteria driving the design. Loads and yaw demands are based on the IEC 61400-1 standard for wind turbine design, and the loads for this examination are extrapolated from the FAST aero elastic design software. The concepts are based...... on a 5 MW offshore turbine. After the system presentation, measurement results are presented to verify the behavior of the system. The loads to the system are applied by torque controlled electrical servo drives, which can add a load of up to 3 MNm to the system. This gives an exact picture of the system...

Reducing rice field algae and cyanobacteria abundance by altering phosphorus fertilizer applications

Science.gov (United States)

In California’s water seeded rice systems algal/cyanobacterial biomass can be a problem during rice establishment. Algal/cyanobacterial growth may be stimulated by phosphorus (P) additions in freshwater habitats, so we set up experiments to evaluate the effects of fertilizer P management on algal/cy...

Influence of Spirulina platensis exudates on the endocrine and nervous systems of a mammalian model

OpenAIRE

Samah M.M. Fathy; Ashraf M.M. Essa

2015-01-01

Objective: To investigate the effect of intra-peritoneal injection of purified exudates of axenic Spirulina platensis on the mammalian endocrine and nervous systems. Methods: The intra-peritoneal injection of the cyanobacterial exudates in mice was applied. Sex hormonal levels of testosterone and progesterone were measured using radioimmunoassay while the follicular stimulating hormone and luteinizing hormone were evaluated by direct chemiluminescence. In addition, superoxide dismutase, ca...

The hetC Gene Is a Direct Target of the NtcA Transcriptional Regulator in Cyanobacterial Heterocyst Development

Science.gov (United States)

Muro-Pastor, Alicia M.; Valladares, Ana; Flores, Enrique; Herrero, Antonia

1999-01-01

The heterocyst is the site of nitrogen fixation in aerobically grown cultures of some filamentous cyanobacteria. Heterocyst development in Anabaena sp. strain PCC 7120 is dependent on the global nitrogen regulator NtcA and requires, among others, the products of the hetR and hetC genes. Expression of hetC, tested by RNA- DNA hybridization, was impaired in an ntcA mutant. A nitrogen-regulated, NtcA-dependent putative transcription start point was localized at nucleotide −571 with respect to the hetC translational start. Sequences upstream from this transcription start point exhibit the structure of the canonical cyanobacterial promoter activated by NtcA, and purified NtcA protein specifically bound to a DNA fragment containing this promoter. Activation of expression of hetC during heterocyst development appears thus to be directly operated by NtcA. NtcA-mediated activation of hetR expression was not impaired in a hetC mutant, indicating that HetC is not an NtcA-dependent element required for hetR induction. PMID:10542167

CIED infection with either pocket or systemic infection presentation

DEFF Research Database (Denmark)

Ihlemann, Nikolaj; Møller-Hansen, Michael; Salado-Rasmussen, Kirsten

2016-01-01

OBJECTIVE: Cardiovascular implantable electronic device (CIED) infections are increasing in numbers. The objective was to review the clinical presentation and outcome in patients affected with CIED infections with either local pocket or systemic presentation. DESIGN: All device removals due to CIED......-up no relapses and two cases of new infections were noted (2.8%). CONCLUSIONS: CIED infection with systemic or pocket infection was difficult to distinguish in clinical presentation and outcome. Complete device removal and antibiotic treatment of long duration was safe and without relapses....

Systemic Lupus Erythematosus Presenting as Acute Adrenal ...

African Journals Online (AJOL)

hanumantp

presented to us with a history of anorexia, progressive darkening of the face ... to us in an acute hypoadrenal state and was found to have Systemic lupus erythematosus with renal involvement. .... Textbook of Endocrinology. 11th ed. Saunders: ...

Case Report: Systemic Lupus Erythematosus Presenting as Acute ...

African Journals Online (AJOL)

We hereby report a case of a 20 year‑old female who presented to us in an acute hypoadrenal state and was found to have Systemic lupus erythematosus with renal involvement. Patient was successfully managed with steroids and improved clinically. Keywords: Addison's disease, Autoimmune diseases, Systemic lupus ...

Harmful algal bloom smart device application: using image analysis and machine learning techniques for early classification of harmful algal blooms (SETAC presentation)

Science.gov (United States)

Reports of toxic cyanobacterial blooms, also known as Harmful Algal Blooms (HABS) have increased drastically in recent years. HABS impact human health from causing mild allergies to liver damage and death. The Ecological Stewardship Institute (ESI) at Northern Kentucky Universi...

Present states and views on vault storage systems

International Nuclear Information System (INIS)

Yoshimura, Eiji

2003-01-01

Storage capacity of spent nuclear fuel storage pools in nuclear power station is reaching to a condition near its limit, and under a condition inevitable on delay of the Pu-thermal utilization plan importance on interim storage of the spent nuclear fuels is further rising. In U.S.A., Germany, and so on, a condition incapable of presenting nuclear energy business itself without its intermediate storage is approaching, so in Japan it will also be a key to smoothly promote the nuclear energy business how the interim storage is used and operated. Under such condition, in Japan storage facilities using a system called by 'metal cask' are established at areas of nuclear power stations to begin their operations. As on the system expensive metal containers are used for storage in themselves, it has a demerit of its high cost. On the other hand, on foreign countries, a storing system called by concrete cask, horizontal silo, or vault is occupying its main stream. Here was introduced present states and future views on vault storage system. (G. K)

Detection and quantification of microcystins (cyanobacterial hepatotoxins) with recombinant antibody fragments isolated from a naïve human phage display library.

Science.gov (United States)

McElhiney, J; Lawton, L A; Porter, A J

2000-12-01

Single-chain antibody fragments against the cyanobacterial hepatotoxin microcystin-LR were isolated from a naive human phage display library and expressed in Escherichia coli. In competition enzyme-linked immunosorbent assay (ELISA), the most sensitive antibody clone selected from the library detected free microcystin-LR with an IC(50) value of 4 microM. It was found to cross react with three other microcystin variants - microcystin-RR, microcystin-LW and microcystin-LF - and detected microcystins in extracts of the cyanobacterium Microcystis aeruginosa, found to contain the toxins by high-performance liquid chromatography (HPLC). The quantification of microcystins in these extracts by ELISA and HPLC showed good correlation. Although the antibody isolated in this study was considerably less sensitive than the polyclonal and monoclonal antibodies already available for microcystin detection, phage display technology represents a cheaper, more rapid alternative for the production of anti-microcystin antibodies than the methods currently in use.

Molecular detection and ecological significance of the cyanobacterial genera Geitlerinema and Leptolyngbya in black band disease of corals.

Science.gov (United States)

Myers, Jamie L; Sekar, Raju; Richardson, Laurie L

2007-08-01

Black band disease (BBD) is a pathogenic, sulfide-rich microbial mat dominated by filamentous cyanobacteria that infect corals worldwide. We isolated cyanobacteria from BBD into culture, confirmed their presence in the BBD community by using denaturing gradient gel electrophoresis (DGGE), and demonstrated their ecological significance in terms of physiological sulfide tolerance and photosynthesis-versus-irradiance values. Twenty-nine BBD samples were collected from nine host coral species, four of which have not previously been investigated, from reefs of the Florida Keys, the Bahamas, St. Croix, and the Philippines. From these samples, seven cyanobacteria were isolated into culture. Cloning and sequencing of the 16S rRNA gene using universal primers indicated that four isolates were related to the genus Geitlerinema and three to the genus Leptolyngbya. DGGE results, obtained using Cyanobacteria-specific 16S rRNA primers, revealed that the most common BBD cyanobacterial sequence, detected in 26 BBD field samples, was related to that of an Oscillatoria sp. The next most common sequence, 99% similar to that of the Geitlerinema BBD isolate, was present in three samples. One Leptolyngbya- and one Phormidium-related sequence were also found. Laboratory experiments using isolates of BBD Geitlerinema and Leptolyngbya revealed that they could carry out sulfide-resistant oxygenic photosynthesis, a relatively rare characteristic among cyanobacteria, and that they are adapted to the sulfide-rich, low-light BBD environment. The presence of the cyanotoxin microcystin in these cultures and in BBD suggests a role in BBD pathogenicity. Our results confirm the presence of Geitlerinema in the BBD microbial community and its ecological significance, which have been challenged, and provide evidence of a second ecologically significant BBD cyanobacterium, Leptolyngbya.

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Science.gov (United States)

Barrington, D. J.; Ghadouani, A.; Ivey, G. N.

2013-06-01

Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H2O2) for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs). The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins) were examined following the addition of H2O2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H2O2 μg-1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H2O2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H2O2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H2O2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Directory of Open Access Journals (Sweden)

D. J. Barrington

2013-06-01

Full Text Available Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H2O2 for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs. The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins were examined following the addition of H2O2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H2O2 μg−1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H2O2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H2O2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H2O2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

Present status of the JT-60 control system

International Nuclear Information System (INIS)

Kimura, T.

1992-01-01

The present status of the control system for a large fusion device of the JT-60 upgrade tokamak is reported including its original design concept, the progress of the system in the past five-year operation and modification for the upgrade. The control system has the features of hierarchical structure, computer control, adoption of CAMAC interfaces and protective interlock by both software and hard-wired systems. Plant monitoring and control are performed by an efficient data communication via CAMAC highways. Sequential discharge control of is executed by a combination of computers and a timing system. A plasma feedback control system with fast 32-bit microprocessors and a man/machine interface with modern workstations have been newly developed for the operation of the JT-60 upgrade. (author)

First evidence of "paralytic shellfish toxins" and cylindrospermopsin in a Mexican freshwater system, Lago Catemaco, and apparent bioaccumulation of the toxins in "tegogolo" snails (Pomacea patula catemacensis).

Science.gov (United States)

Berry, John P; Lind, Owen

2010-05-01

Exposure to cyanobacterial toxins in freshwater systems, including both direct (e.g., drinking water) and indirect (e.g., bioaccumulation in food webs) routes, is emerging as a potentially significant threat to human health. We investigated cyanobacterial toxins, specifically cylindrospermopsin (CYN), the microcystins (MCYST) and the "paralytic shellfish toxins" (PST), in Lago Catemaco (Veracruz, Mexico). Lago Catemaco is a tropical lake dominated by Cylindrospermopsis, specifically identified as Cylindrospermopsis catemaco and Cylindrospermopsis philippinensis, and characterized by an abundant, endemic species of snail (Pomacea patula catemacensis), known as "tegogolos," that is both consumed locally and commercially important. Samples of water, including dissolved and particulate fractions, as well as extracts of tegogolos, were screened using highly specific and sensitive ELISA. ELISA identified CYN and PST at low concentrations in only one sample of seston; however, both toxins were detected at appreciable quantities in tegogolos. Calculated bioaccumulation factors (BAF) support bioaccumulation of both toxins in tegogolos. The presence of CYN in the phytoplankton was further confirmed by HPLC-UV and LC-MS, following concentration and extraction of algal cells, but the toxin could not be confirmed by these methods in tegogolos. These data represent the first published evidence for CYN and the PST in Lago Catemaco and, indeed, for any freshwater system in Mexico. Identification of the apparent bioaccumulation of these toxins in tegogolos may suggest the need to further our understanding of the transfer of cyanobacterial toxins in freshwater food webs as it relates to human health. Copyright 2009 Elsevier Ltd. All rights reserved.

Microcystin Prevalence throughout Lentic Waterbodies in Coastal Southern California

Directory of Open Access Journals (Sweden)

Meredith D. A. Howard

2017-07-01

Full Text Available Toxin producing cyanobacterial blooms have increased globally in recent decades in both frequency and intensity. Despite the recognition of this growing risk, the extent and magnitude of cyanobacterial blooms and cyanotoxin prevalence is poorly characterized in the heavily populated region of southern California. Recent assessments of lentic waterbodies (depressional wetlands, lakes, reservoirs and coastal lagoons determined the prevalence of microcystins and, in some cases, additional cyanotoxins. Microcystins were present in all waterbody types surveyed although toxin concentrations were generally low across most habitats, as only a small number of sites exceeded California’s recreational health thresholds for acute toxicity. Results from passive samplers (Solid Phase Adsorption Toxin Tracking (SPATT indicated microcystins were prevalent throughout lentic waterbodies and that traditional discrete samples underestimated the presence of microcystins. Multiple cyanotoxins were detected simultaneously in some systems, indicating multiple stressors, the risk of which is uncertain since health thresholds are based on exposures to single toxins. Anatoxin-a was detected for the first time from lakes in southern California. The persistence of detectable microcystins across years and seasons indicates a low-level, chronic risk through both direct and indirect exposure. The influence of toxic cyanobacterial blooms is a more complex stressor than presently recognized and should be included in water quality monitoring programs.

Greener on the Other Side: How Increased Urea Use may Promote Cyanobacterial Blooms

Science.gov (United States)

Erratt, K. J.; Creed, I. F.; Trick, C. G.

2017-12-01

The frequency of freshwater cyanobacterial blooms is on the rise in temperate regions around the world. The widespread use of chemical fertilizers linked to modern agricultural practices has enhanced the fertility of surface waters promoting the expansion of cyanobacteria dominated harmful algal blooms. While phosphorus (P) has been recognized as the principal agent regulating phytoplankton productivity in inland waters, elevated P is not the universal trigger for bloom initiation. P fertilizer applications across the globe have been outpaced by nitrogen (N) fertilizer use. Not only has the load of N entering surface waters increased, but its chemical composition has been altered. The use of inorganic-N fertilizers has been waned in favor of urea-based products, with urea now accounting for more than half of total N-fertilizer applications worldwide. This contemporary shift in fertilizer usage has coincided with the rise of cyanobacteria dominated harmful algal blooms in freshwaters. Here, we examined the relative success of urea as a N-source relative to inorganic N forms (NO3-, NH4+) for three common bloom-forming species of cyanobacteria: Microcystis aeruginosa, Dolichospermum flos-aque, and Synechococcus sp. We found that (1) urea was consistently drawdown more rapidly relative to inorganic N substrates, suggesting that cyanobacteria exhibit a preference for urea over inorganic N forms; (2) cyanobacteria consume urea in excess of cellular requirements; and (3) urea may offer cyanobacteria a competitive edge over eukaryotic algae by enhancing light absorption capabilities. As we push forward into the 21st century, our reliance on urea-based fertilizers is projected to escalate and it is critical that we understand the unintended consequences urea discharge could be having on receiving freshwaters.

On the present status of the ARAMAKO system

International Nuclear Information System (INIS)

Nikolaev, M.N.; Savos'kin, M.M.

1987-01-01

This paper reviews the present status of the ARAMAKO multigroup constant calculation system for solving neutron and gamma quantum transport equations and for calculations of linear and bilinear functionals of their fields. (author)

Controlling cyanobacterial blooms in hypertrophic Lake Taihu, China: will nitrogen reductions cause replacement of non-N2 fixing by N2 fixing taxa?

Directory of Open Access Journals (Sweden)

Hans W Paerl

Full Text Available Excessive anthropogenic nitrogen (N and phosphorus (P inputs have caused an alarming increase in harmful cyanobacterial blooms, threatening sustainability of lakes and reservoirs worldwide. Hypertrophic Lake Taihu, China's third largest freshwater lake, typifies this predicament, with toxic blooms of the non-N2 fixing cyanobacteria Microcystis spp. dominating from spring through fall. Previous studies indicate N and P reductions are needed to reduce bloom magnitude and duration. However, N reductions may encourage replacement of non-N2 fixing with N2 fixing cyanobacteria. This potentially counterproductive scenario was evaluated using replicate, large (1000 L, in-lake mesocosms during summer bloom periods. N+P additions led to maximum phytoplankton production. Phosphorus enrichment, which promoted N limitation, resulted in increases in N2 fixing taxa (Anabaena spp., but it did not lead to significant replacement of non-N2 fixing with N2 fixing cyanobacteria, and N2 fixation rates remained ecologically insignificant. Furthermore, P enrichment failed to increase phytoplankton production relative to controls, indicating that N was the most limiting nutrient throughout this period. We propose that Microcystis spp. and other non-N2 fixing genera can maintain dominance in this shallow, highly turbid, nutrient-enriched lake by outcompeting N2 fixing taxa for existing sources of N and P stored and cycled in the lake. To bring Taihu and other hypertrophic systems below the bloom threshold, both N and P reductions will be needed until the legacy of high N and P loading and sediment nutrient storage in these systems is depleted. At that point, a more exclusive focus on P reductions may be feasible.

Molecular Detection and Ecological Significance of the Cyanobacterial Genera Geitlerinema and Leptolyngbya in Black Band Disease of Corals▿ †

Science.gov (United States)

Myers, Jamie L.; Sekar, Raju; Richardson, Laurie L.

2007-01-01

Black band disease (BBD) is a pathogenic, sulfide-rich microbial mat dominated by filamentous cyanobacteria that infect corals worldwide. We isolated cyanobacteria from BBD into culture, confirmed their presence in the BBD community by using denaturing gradient gel electrophoresis (DGGE), and demonstrated their ecological significance in terms of physiological sulfide tolerance and photosynthesis-versus-irradiance values. Twenty-nine BBD samples were collected from nine host coral species, four of which have not previously been investigated, from reefs of the Florida Keys, the Bahamas, St. Croix, and the Philippines. From these samples, seven cyanobacteria were isolated into culture. Cloning and sequencing of the 16S rRNA gene using universal primers indicated that four isolates were related to the genus Geitlerinema and three to the genus Leptolyngbya. DGGE results, obtained using Cyanobacteria-specific 16S rRNA primers, revealed that the most common BBD cyanobacterial sequence, detected in 26 BBD field samples, was related to that of an Oscillatoria sp. The next most common sequence, 99% similar to that of the Geitlerinema BBD isolate, was present in three samples. One Leptolyngbya- and one Phormidium-related sequence were also found. Laboratory experiments using isolates of BBD Geitlerinema and Leptolyngbya revealed that they could carry out sulfide-resistant oxygenic photosynthesis, a relatively rare characteristic among cyanobacteria, and that they are adapted to the sulfide-rich, low-light BBD environment. The presence of the cyanotoxin microcystin in these cultures and in BBD suggests a role in BBD pathogenicity. Our results confirm the presence of Geitlerinema in the BBD microbial community and its ecological significance, which have been challenged, and provide evidence of a second ecologically significant BBD cyanobacterium, Leptolyngbya. PMID:17601818

A Vision for Systems Engineering Applied to Wind Energy (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Felker, F.; Dykes, K.

2015-01-01

This presentation was given at the Third Wind Energy Systems Engineering Workshop on January 14, 2015. Topics covered include the importance of systems engineering, a vision for systems engineering as applied to wind energy, and application of systems engineering approaches to wind energy research and development.

The occurrence of cyanobacteria in pulp and paper waste-treatment systems.

Science.gov (United States)

Kirkwood, A E; Nalewajko, C; Fulthorpe, R R

2001-08-01

Pulp and paper secondary waste-treatment systems in Brazil, Canada, New Zealand, and the U.S.A. contained dynamic cyanobacterial communities, some of which exceeded heterotrophic bacterial biomass. No other viable photoautotrophic populations were detected in the ponds. Regardless of geographical location, Oscillatoriales including Phormidium, Geitlerinema, and Pseudanabaena were the dominant taxa. As well, Chroococcus (Chroococcales) was an important genus in Brazil and New Zealand. The possible impact of cyanobacteria on waste-treatment efficiency deserves further study given their large biomass and diverse metabolic characteristics.

Cyanotoxins from black band disease of corals and from other coral reef environments.

Science.gov (United States)

Gantar, Miroslav; Sekar, Raju; Richardson, Laurie L

2009-11-01

Many cyanobacteria produce cyanotoxins, which has been well documented from freshwater environments but not investigated to the same extent in marine environments. Cyanobacteria are an obligate component of the polymicrobial disease of corals known as black band disease (BBD). Cyanotoxins were previously shown to be present in field samples of BBD and in a limited number of BBD cyanobacterial cultures. These toxins were suggested as one of the mechanisms contributing to BBD-associated coral tissue lysis and death. In this work, we tested nine cyanobacterial isolates from BBD and additionally nine isolated from non-BBD marine sources for their ability to produce toxins. The presence of toxins was determined using cell extracts of laboratory grown cyanobacterial cultures using ELISA and the PP2A assay. Based on these tests, it was shown that cyanobacterial toxins belonging to the microcystin/nodularin group were produced by cyanobacteria originating from both BBD and non-BBD sources. Several environmental factors that can be encountered in the highly dynamic microenvironment of BBD were tested for their effect on both cyanobacterial growth yield and rate of toxin production using two of the BBD isolates of the genera Leptolyngbya and Geitlerinema. While toxin production was the highest under mixotrophic conditions (light and glucose) for the Leptolyngbya isolate, it was highest under photoautotrophic conditions for the Geitlerinema isolate. Our results show that toxin production among marine cyanobacteria is more widespread than previously documented, and we present data showing three marine cyanobacterial genera (Phormidium, Pseudanabaena, and Spirulina) are newly identified as cyanotoxin producers. We also show that cyanotoxin production by BBD cyanobacteria can be affected by environmental factors that are present in the microenvironment associated with this coral disease.

Heterologous Production of Cyanobacterial Mycosporine-Like Amino Acids Mycosporine-Ornithine and Mycosporine-Lysine in Escherichia coli

Science.gov (United States)

Katoch, Meenu; Mazmouz, Rabia; Chau, Rocky; Pearson, Leanne A.; Pickford, Russell

2016-01-01

ABSTRACT Mycosporine-like amino acids (MAAs) are an important class of secondary metabolites known for their protection against UV radiation and other stress factors. Cyanobacteria produce a variety of MAAs, including shinorine, the active ingredient in many sunscreen creams. Bioinformatic analysis of the genome of the soil-dwelling cyanobacterium Cylindrospermum stagnale PCC 7417 revealed a new gene cluster with homology to MAA synthase from Nostoc punctiforme. This newly identified gene cluster is unusual because it has five biosynthesis genes (mylA to mylE), compared to the four found in other MAA gene clusters. Heterologous expression of mylA to mylE in Escherichia coli resulted in the production of mycosporine-lysine and the novel compound mycosporine-ornithine. To our knowledge, this is the first time these compounds have been heterologously produced in E. coli and structurally characterized via direct spectral guidance. This study offers insight into the diversity, biosynthesis, and structure of cyanobacterial MAAs and highlights their amenability to heterologous production methods. IMPORTANCE Mycosporine-like amino acids (MAAs) are significant from an environmental microbiological perspective as they offer microbes protection against a variety of stress factors, including UV radiation. The heterologous expression of MAAs in E. coli is also significant from a biotechnological perspective as MAAs are the active ingredient in next-generation sunscreens. PMID:27520810

To prevent the occurrence of black water agglomerate through delaying decomposition of cyanobacterial bloom biomass by sediment microbial fuel cell.

Science.gov (United States)

Zhou, Yan-Li; Jiang, He-Long; Cai, Hai-Yuan

2015-04-28

Settlement of cyanobacterial bloom biomass (CBB) into sediments in eutrophic lakes often induced the occurrence of black water agglomerate and then water quality deterioration. This study investigated the effect of sediment microbial fuel cell (SMFC) on CBB removal in sediments and related water pollution. Sediment bulking and subsequent black water from decomposition of settled CBB happened without SMFC, but were not observed over 100-day experiments with SMFC employment. While CBB in sediments improved power production from SMFC, the removal efficiency of organic matters in CBB-amended sediments with SMFC was significantly lower than that without SMFC. Pyrosequencing analysis showed higher abundances of the fermentative Clostridium and acetoclastic methanogen in CBB-amended bulk sediments without SMFC than with SMFC at the end of experiments. Obviously, SMFC operation changed the microbial community in CBB-amended sediments, and delayed the CBB degradation against sediment bulking. Thus, SMFC could be potentially applied as pollution prevention in CBB-settled and sensitive zones in shallow lakes. Copyright © 2015 Elsevier B.V. All rights reserved.

Presentation Attack Detection for Iris Recognition System Using NIR Camera Sensor

Science.gov (United States)

Nguyen, Dat Tien; Baek, Na Rae; Pham, Tuyen Danh; Park, Kang Ryoung

2018-01-01

Among biometric recognition systems such as fingerprint, finger-vein, or face, the iris recognition system has proven to be effective for achieving a high recognition accuracy and security level. However, several recent studies have indicated that an iris recognition system can be fooled by using presentation attack images that are recaptured using high-quality printed images or by contact lenses with printed iris patterns. As a result, this potential threat can reduce the security level of an iris recognition system. In this study, we propose a new presentation attack detection (PAD) method for an iris recognition system (iPAD) using a near infrared light (NIR) camera image. To detect presentation attack images, we first localized the iris region of the input iris image using circular edge detection (CED). Based on the result of iris localization, we extracted the image features using deep learning-based and handcrafted-based methods. The input iris images were then classified into real and presentation attack categories using support vector machines (SVM). Through extensive experiments with two public datasets, we show that our proposed method effectively solves the iris recognition presentation attack detection problem and produces detection accuracy superior to previous studies. PMID:29695113

Presentation Attack Detection for Iris Recognition System Using NIR Camera Sensor

Directory of Open Access Journals (Sweden)

Dat Tien Nguyen

2018-04-01

Full Text Available Among biometric recognition systems such as fingerprint, finger-vein, or face, the iris recognition system has proven to be effective for achieving a high recognition accuracy and security level. However, several recent studies have indicated that an iris recognition system can be fooled by using presentation attack images that are recaptured using high-quality printed images or by contact lenses with printed iris patterns. As a result, this potential threat can reduce the security level of an iris recognition system. In this study, we propose a new presentation attack detection (PAD method for an iris recognition system (iPAD using a near infrared light (NIR camera image. To detect presentation attack images, we first localized the iris region of the input iris image using circular edge detection (CED. Based on the result of iris localization, we extracted the image features using deep learning-based and handcrafted-based methods. The input iris images were then classified into real and presentation attack categories using support vector machines (SVM. Through extensive experiments with two public datasets, we show that our proposed method effectively solves the iris recognition presentation attack detection problem and produces detection accuracy superior to previous studies.

Presentation Attack Detection for Iris Recognition System Using NIR Camera Sensor.

Science.gov (United States)

Nguyen, Dat Tien; Baek, Na Rae; Pham, Tuyen Danh; Park, Kang Ryoung

2018-04-24

Among biometric recognition systems such as fingerprint, finger-vein, or face, the iris recognition system has proven to be effective for achieving a high recognition accuracy and security level. However, several recent studies have indicated that an iris recognition system can be fooled by using presentation attack images that are recaptured using high-quality printed images or by contact lenses with printed iris patterns. As a result, this potential threat can reduce the security level of an iris recognition system. In this study, we propose a new presentation attack detection (PAD) method for an iris recognition system (iPAD) using a near infrared light (NIR) camera image. To detect presentation attack images, we first localized the iris region of the input iris image using circular edge detection (CED). Based on the result of iris localization, we extracted the image features using deep learning-based and handcrafted-based methods. The input iris images were then classified into real and presentation attack categories using support vector machines (SVM). Through extensive experiments with two public datasets, we show that our proposed method effectively solves the iris recognition presentation attack detection problem and produces detection accuracy superior to previous studies.

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

small and large-sized sphaeromorphs;complex acanthomorphs,cyanobacterial community;especially a very small-sized but exceptionally well preserved Obruchevella ,a form resembling Volvox colonies; cf.vase-shaped microfossils and ...

Data-acquisition systems for the present and the future

International Nuclear Information System (INIS)

Drobnis, D.D.

1982-09-01

Basic components of today's acquisition systems are surveyed. These include front-end tools such as microprocessors, programmable controllers, and CAMAC interfaces. Some key concepts in large central real-time systems are examined: Hardware and Software architecture, and data base structure. Some trends in present data acquisition system design are analyzed, including increasing distribution of system functions and expansion to hierarchical multi-processor netowrks. With the evolution of microprocessors, front-end intelligence is growing into front-end computing power. Real-time host systems are becoming increasingly sophisticated human interface and data base management tools, with increasingly complex operating systems, and increasing amounts of memory, mass storage, and computing power. And the ultimate analysis of plasma data is becoming increasingly sophisticated

Primary Systemic Amyloidosis Presenting as Swollen Dense Breast: A Case Report

International Nuclear Information System (INIS)

Lee, Byung Hoon; Kim, Mi Young; Kim, Su Young; Hwang, Yoon Joon; Han, Yoon Hee; Seo, Jung Wook; Kim, Yong Hoon; Cha, Soon Joo; Hur, Gham; Joo, Mee

2006-01-01

Breast involvement of primary systemic amyloidosis is rare. This is a rare case of breast amyloidosis presenting as a diffuse infiltrative lesion. We present the mammographic, ultrasound, and MR findings of a systemic primary amyloidosis involving the breast with diffuse infiltrative pattern

Communication-based positioning systems: past, present and prospects

International Nuclear Information System (INIS)

Ma Guanyi; Wan Qingtao; Gan Tong

2012-01-01

This paper reviews positioning systems in the context of communication systems. First, the basic positioning technique is described for location based service (LBS) in mobile communication systems. Then the high integrity global positioning system (iGPS) is introduced in terms of aspects of what it is and how the low Earth orbit (LEO) Iridium telecommunication satellites enhance the global positioning system (GPS). Emphasis is on the Chinese Area Positioning System (CAPS) which is mainly based on commercial geostationary (GEO) communication satellites, including decommissioned GEO and inclined geosynchronous communication satellites. Characterized by its low cost, high flexibility, wide-area coverage and ample frequency resources, a distinctive feature of CAPS is that its navigation messages are generated on the ground, then uploaded to and forwarded by the communication satellites. Fundamental principles and key technologies applied in the construction of CAPS are presented in detail from the CAPS validation phase to its experimental system setup. A prospective view of CAPS has concluded it to be a seamless, high accuracy, large capacity navigation and communication system which can be achieved by expanding it world wide and enhancing it with LEO satellites and mobile base stations. Hence, this system is a potential candidate for the next generation of radio navigation after GPS. (invited reviews)

Spatial and Temporal Dynamics of Potentially Toxic Cyanobacteria in the Riverine Region of a Temperate Estuarine System Altered by Weirs

Directory of Open Access Journals (Sweden)

Jacqueline Martha Malazarte

2017-10-01

Full Text Available The effects of weirs on fish and other biological communities have garnered considerable study, whereas the effects of weirs on community composition of toxic cyanobacteria have not yet been well documented. In this study, temporal and spatial variations in species composition and the abundance of potentially toxic cyanobacteria were investigated in the riverine regions of the temperate Youngsan River estuary, where two weirs have recently been constructed. Four stations were sampled 0.5 m below the surface monthly along the channel of the upper river from May 2014 to April 2015 to explore cyanobacterial composition and abundance, while physicochemical and biological parameters were measured to elucidate possible mechanisms controlling these dynamics. Two stations were located upstream at free-flowing sites, and the other stations were located downstream at impounded sites near the weirs. Twenty-eight cyanobacterial species were identified, seven of which were potentially toxic: Microcystis sp., M. aeruginosa, M. flos-aquae, Dolichospermum sp., Aphanocapsa sp., Oscillatoria sp. and Phormidium sp. Microcystis sp. was the most abundant in June 2014 at the lowest station near the weir. Meanwhile, Phormidium sp. occurred at low abundance throughout the study period, except during the winter months, when its abundance was elevated. The interactive forward selection method highlighted dissolved inorganic nitrogen and zooplankton abundance as explanatory variables for this observed variation, but their effects on cyanobacterial growth are unclear. However, temperature was the major determinant for the temporal variation in cyanobacterial populations. Cluster analysis showed that the downstream stations near the weirs had a high similarity of potentially toxic cyanobacteria. Significantly higher abundance, especially of Microcystis sp., was also recorded at the impounded sites suggesting that the presence of weirs might affect variations in toxic

Systemic lupus erythematosus presenting as morbid jealousy.

Science.gov (United States)

Ravindran, A.; Carney, M. W.; Denman, A. M.

1980-01-01

A patient fulfilling the diagnostic criteria for systemic lupus erythematosus and presenting with morbid jealousy is described. There was evidence of cerebral lupus. Her physical and mental symptoms responded to a combination of chlorpromazine and steroids. The morbid mental process was probably caused by her physical condition while the content of her disordered thought and behaviour was determined by her introverted premorbid personality, religiosity, unhappy childhood experiences and frustrated desire for children. PMID:7413541

A pediatric renal lymphoma case presenting with central nervous system findings.

Science.gov (United States)

Baran, Ahmet; Küpeli, Serhan; Doğru, Omer

2013-06-01

In pediatric patients renal lymphoma frequently presents in the form of multiple, bilateral mass lesions, infrequently as a single or retroperitoneal mass, and rarely as diffuse infiltrative lesions. In patients with apparent central nervous system involvement close attention to other physical and laboratory findings are essential for preventing a delay in the final diagnosis. Herein we present a pediatric patient with renal lymphoma that presented with central nervous system findings that caused a delay in diagnosis. None declared.

Macrophage Activation Syndrome as Initial Presentation of Systemic Lupus Erythematosus

Directory of Open Access Journals (Sweden)

Say-Tin Yeap

2008-04-01

Full Text Available Macrophage activation syndrome (MAS is known to be a severe and potentially life-threatening complication of rheumatic disorder, especially systemic juvenile rheumatoid arthritis. It is very rare for MAS to be an initial presentation of systemic lupus erythematosus (SLE. Here, we report a 14-year-old girl in whom MAS developed as an initial presentation of SLE. With early diagnosis and administration of cyclosporine A, she had a fair outcome. Further testing showed positive anti-dsDNA about 8 months later.

The cyanobacterial lectin scytovirin displays potent in vitro and in vivo activity against Zaire Ebola virus.

Science.gov (United States)

Garrison, Aura R; Giomarelli, Barbara G; Lear-Rooney, Calli M; Saucedo, Carrie J; Yellayi, Srikanth; Krumpe, Lauren R H; Rose, Maura; Paragas, Jason; Bray, Mike; Olinger, Gene G; McMahon, James B; Huggins, John; O'Keefe, Barry R

2014-12-01

The cyanobacterial lectin scytovirin (SVN) binds with high affinity to mannose-rich oligosaccharides on the envelope glycoprotein (GP) of a number of viruses, blocking entry into target cells. In this study, we assessed the ability of SVN to bind to the envelope GP of Zaire Ebola virus (ZEBOV) and inhibit its replication. SVN interacted specifically with the protein's mucin-rich domain. In cell culture, it inhibited ZEBOV replication with a 50% virus-inhibitory concentration (EC50) of 50 nM, and was also active against the Angola strain of the related Marburg virus (MARV), with a similar EC50. Injected subcutaneously in mice, SVN reached a peak plasma level of 100 nm in 45 min, but was cleared within 4h. When ZEBOV-infected mice were given 30 mg/kg/day of SVN by subcutaneous injection every 6h, beginning the day before virus challenge, 9 of 10 animals survived the infection, while all infected, untreated mice died. When treatment was begun one hour or one day after challenge, 70-90% of mice survived. Quantitation of infectious virus and viral RNA in samples of serum, liver and spleen collected on days 2 and 5 postinfection showed a trend toward lower titers in treated than control mice, with a significant decrease in liver titers on day 2. Our findings provide further evidence of the potential of natural lectins as therapeutic agents for viral infections. Published by Elsevier B.V.

Scanning with a Total Information Storage and Controlled Data Presentation System

Energy Technology Data Exchange (ETDEWEB)

Rejali, A. M.; Gregg, E. C.; Voelker, W. H.; Friedell, H. L. [Case Western Reserve University, Cleveland, OH (United States)

1969-01-15

This presentation demonstrates improved clinical results obtained from storing all available information received by the detector or detectors without prior modifications in a permanent memory. Permanently stored information is modified later with a special electronic imaging system with kinescope presentation in black and white or colour. Under carefully controlled circumstances this system permits immediate and innumerable degrees of erase and contrast enhancement or colour coding in fractions of a second. A profile representing the count-rate through any slice in the scanned area may be performed to determine relative distribution of radioisotopes. The advantage of this system and various clinical results in scans of myocardiums, pancreas, cardiac blood pool, placenta, etc. will be presented. (author)

Robust Synchronization Models for Presentation System Using SMIL-Driven Approach

Science.gov (United States)

Asnawi, Rustam; Ahmad, Wan Fatimah Wan; Rambli, Dayang Rohaya Awang

2013-01-01

Current common Presentation System (PS) models are slide based oriented and lack synchronization analysis either with temporal or spatial constraints. Such models, in fact, tend to lead to synchronization problems, particularly on parallel synchronization with spatial constraints between multimedia element presentations. However, parallel…

Engineering the presentation layer of adaptable web information systems

NARCIS (Netherlands)

Fiala, Z.; Frasincar, F.; Hinz, M.; Houben, G.J.P.M.; Barna, P.; Meissner, K.; Koch, N.; Fraternali, P.; Wirsing, M.

2004-01-01

Engineering adaptable Web Information Systems (WIS) requires systematic design models and specification frameworks. A complete model-driven methodology like Hera distinguishes between the conceptual, navigational, and presentational aspects of WIS design and identifies different adaptation hot-spots

Circulation Systems Past and Present

Directory of Open Access Journals (Sweden)

Maurice J. Freedman

1981-01-01

Full Text Available A review of the development of circulation systems shows two areas of change. The librarian's perception of circulation control has shifted from a broad service orientation to a narrow record-keeping approach and recently back again. The technological development of circulation sys-tems has evolved from manual systems to the online systems of today. The trade-offs and deficiencies of earlier systems in relation to the comprehensive services made possible by the online computer are detailed.

Prediction-error identification of LPV systems : present and beyond

NARCIS (Netherlands)

Toth, R.; Heuberger, P.S.C.; Hof, Van den P.M.J.; Mohammadpour, J.; Scherer, C. W.

2012-01-01

The proposed chapter aims at presenting a unified framework of prediction-error based identification of LPV systems using freshly developed theoretical results. Recently, these methods have got a considerable attention as they have certain advantages in terms of computational complexity, optimality

Presenting a Multi-level Superstructure Optimization Approach for Mechatronic System Design

DEFF Research Database (Denmark)

Pedersen, Henrik C.; Andersen, Torben Ole; Bech, Michael Møller

2010-01-01

Synergism and integration in the design process is what sets apart a Mechatronic System from a traditional, multidisciplinary system. However the typical design approach has been to divide the design problem into sub problems for each technology area (mechanics, electronics and control) and descr......Synergism and integration in the design process is what sets apart a Mechatronic System from a traditional, multidisciplinary system. However the typical design approach has been to divide the design problem into sub problems for each technology area (mechanics, electronics and control......) and describe the interface between the technologies, whereas the lack of well-established, systematic engineering methods to form the basic set-off in analysis and design of complete mechatronic systems has been obvious. The focus of the current paper is therefore to present an integrated design approach...... for mechatronic system design, utilizing a multi-level superstructure optimization based approach. Finally two design examples are presented and the possibilities and limitations of the approach are outlined....

Bacterial community composition of size-fractioned aggregates within the phycosphere of cyanobacterial blooms in a eutrophic freshwater lake.

Directory of Open Access Journals (Sweden)

Haiyuan Cai

Full Text Available Bacterial community composition of different sized aggregates within the Microcystis cyanobacterial phycosphere were determined during summer and fall in Lake Taihu, a eutrophic lake in eastern China. Bloom samples taken in August and September represent healthy bloom biomass, whereas samples from October represent decomposing bloom biomass. To improve our understanding of the complex interior structure in the phycosphere, bloom samples were separated into large (>100 µm, medium (10-100 µm and small (0.2-10 µm size aggregates. Species richness and library coverage indicated that pyrosequencing recovered a large bacterial diversity. The community of each size aggregate was highly organized, indicating highly specific conditions within the Microcystis phycosphere. While the communities of medium and small-size aggregates clustered together in August and September samples, large- and medium-size aggregate communities in the October sample were grouped together and distinct from small-size aggregate community. Pronounced changes in the absolute and relative percentages of the dominant genus from the two most important phyla Proteobacteria and Bacteroidetes were observed among the various size aggregates. Bacterial species on large and small-size aggregates likely have the ability to degrade high and low molecular weight compounds, respectively. Thus, there exists a spatial differentiation of bacterial taxa within the phycosphere, possibly operating in sequence and synergy to catalyze the turnover of complex organic matters.

Experimental manipulation of TN:TP ratiossuppress cyanobacterial biovolume and microcystinconcentration in large-scale in situ mesocosms

Science.gov (United States)

Harris, Theodore D.; Wilhelm, Frank M.; Graham, Jennifer L.; Loftin, Keith A.

2014-01-01

A global dataset was compiled to examine relations between the total nitrogen to total phosphorus ratio (TN:TP) and microcystin concentration in lakes and reservoirs. Microcystin concentration decreased as TN:TP ratios increased, suggesting that manipulation of the TN:TP ratio may reduce microcystin concentrations. This relationship was experimentally tested by adding ammonium nitrate to increase the TN:TP ratio in large-scale (70 m3), in situ mesocosms located in a eutrophic reservoir that routinely experiences toxic blooms of cyanobacteria. At a TN:TP ratio >75:1, chlorophytes dominated the phytoplankton community in the mesocosms, while cyanobacterial biovolume was significantly reduced and microcystin was not detected. In contrast, the unmanipulated reservoir was dominated by cyanobacteria, and microcystin was detected. Secchi depths were 1.1 to 1.8 times greater in the mesocosms relative to the reservoir. Cladoceran zooplankton had a larger body size (0.14 mm on average) in the mesocosms compared to conspecifics in the reservoir, which was likely related to the higher quality food. Combined, these empirical and experimental data indicate that although nutrient addition is counterintuitive to current cyanobacteria management practices, increasing the TN:TP ratio by adding nitrogen may be a potential short-term management strategy to reduce cyanobacteria and cyanotoxins when other alternatives (e.g., phosphorus reduction) are not possible. Additional experimental studies with careful controls are needed to define best management practices and identify any potential unintended consequences before nitrogen addition is implemented as a lake and reservoir management practice.

Toroidal Continuously Variable Transmission Systems: Terminology and Present Studies

Directory of Open Access Journals (Sweden)

Ahmet YILDIZ

2014-04-01

Full Text Available The use of continuously variable transmission systems in many different areas such as aerospace, robotics, machinery and automotive industries as an alternative to conventional speed changers with constant ratio becomes widely.Especially in the automotive industry, these systems have been used increasingly, since they enable that internal combustion engines in vehicles run at optimal speeds, and consequently provide considerable fuel savings and therefore lower emission values and also they provide powerful acceleration and quiet working. CVT systems have several constructive variants such as belted, chained, balled, toroidal etc. In this paper, toroidal CVT systems based on elastohydrodynamic principles are concerned with, and fundamental works of last two decades in this field are reviewed. However, the relevant terminology and dynamics along with the control of these systems are briefly treated for better understanding of the literature mentioned. Attention is drawn to the lack of some significant issues in present research works, and potential future works are pointed out. This paper, to the authors’ knowledge, will be the first review on toroidal CVT systems in Turkish literature

Status of the present ATLAS RPC system and overview towards HL-LHC

CERN Document Server

Alberghi, Gian Luigi; The ATLAS collaboration

2018-01-01

The RPC system covers the barrel region of the ATLAS muon spectrometer in the pseudo-rapidity range of |eta|<1.05 with six independent detector layers, and solely provides the L1 trigger signal and the track coordinate in the non-bending plane of the muon candidates. The system has been designed to operate up to the nominal LHC luminosity (1e34cm-2s-1) which has been already exceeded thanks to the excellent performance of the collider. The experience in operating the present RPC system, up to the maximum instantaneous luminosity of 2.05 x 1e34 cm-2 s-1 reached in 2017, is reported. The performance of the system, in the severe background and pileup conditions of the last data taking period, is presented together with the improved tools implemented in order to have an effective monitoring of the detector status. The plans to successfully operate the present system during the HL-LHC phase are also introduced.

EXCEPTIONALLY RARE VARIANTS OF THE URINARY SYSTEM ANOMALIES - ROENTGEN PRESENTATION

Directory of Open Access Journals (Sweden)

Rade R. Babić

2002-07-01

Full Text Available The results of the radiological study of the urinary system anomalies are presented on the material consisting of 8,568 urographies done from 1990 to 2001 at the Institute for Radiology, Niš. The paper shows exceptionally rare anomalies of the urinary system: a horse-shoe shaped kidney with pyelocaliceal systems in its arms and isthmus, heterolateral ectopia of the kidney with fusion, abdominal-medial ectopia of the kidney with ventral malrotation and cup hyperplasia, hypoplastic cup, triple pyeolcaliceal system, M. Lenarduzzi and blind-ending of the Y-shaped urethra. The author concludes that, for the sake of performing every day professional work, it is necessary to possess detailed knowledge of the rarest urinary system anomalies.

Arabinogalactan proteins occur in the free-living cyanobacterium genus Nostoc and in plant-Nostoc symbioses.

Science.gov (United States)

Jackson, Owen; Taylor, Oliver; Adams, David G; Knox, J Paul

2012-10-01

Arabinogalactan proteins (AGP) are a diverse family of proteoglycans associated with the cell surfaces of plants. AGP have been implicated in a wide variety of plant cell processes, including signaling in symbioses. This study investigates the existence of putative AGP in free-living cyanobacterial cultures of the nitrogen-fixing, filamentous cyanobacteria Nostoc punctiforme and Nostoc sp. strain LBG1 and at the symbiotic interface in the symbioses between Nostoc spp. and two host plants, the angiosperm Gunnera manicata (in which the cyanobacterium is intracellular) and the liverwort Blasia pusilla (in which the cyanobacterium is extracellular). Enzyme-linked immunosorbent assay, immunoblotting, and immunofluorescence analyses demonstrated that three AGP glycan epitopes (recognized by monoclonal antibodies LM14, MAC207, and LM2) are present in free-living Nostoc cyanobacterial species. The same three AGP glycan epitopes are present at the Gunnera-Nostoc symbiotic interface and the LM2 epitope is detected during the establishment of the Blasia-Nostoc symbiosis. Bioinformatic analysis of the N. punctiforme genome identified five putative AGP core proteins that are representative of AGP classes found in plants. These results suggest a possible involvement of AGP in cyanobacterial-plant symbioses and are also suggestive of a cyanobacterial origin of AGP.

Progress and present status of ITER cryoline system

International Nuclear Information System (INIS)

Badgujar, S.; Bonneton, M.; Chalifour, M.; Forgeas, A.; Serio, L.; Sarkar, B.; Shah, N.

2014-01-01

The cryoline system at ITER forms a very complex network localized inside the Tokamak building, on a dedicated plant bridge and in cryoplant areas. The cooling power produced in the cryoplant is distributed via these lines with a total length of about 3.7 km and interconnecting all the cold boxes of the cryogenic system as well as the cold boxes of various clients (magnets, cryopumps and thermal shield). Distinct layouts and polygonal geometry, nuclear safety and confinement requirements, difficult installation and in-service inspection/repair demand very high reliability and availability for the cryolines. The finalization of the building-embedded plates for supporting the lines, before the detailed design, has made this project technologically more challenging. The conceptual design phase has been completed and procurement arrangements have been signed with India, responsible for providing the system of cryolines and warm lines to ITER, as in kind contribution. The prototype test for the design and performance validation has been planned on a representative cryoline section. After describing the basic features and general layout of the ITER cryolines, the paper presents key design requirements, conceptual design approach, progress and status of the cryolines project as well as challenges to build such a complex cryoline system

Systemic non-Hodgkin's lymphoma initially presenting as a bladder mass

Directory of Open Access Journals (Sweden)

Naveen Kumar Gupta

2017-01-01

Full Text Available Urinary bladder lymphomas are rare lesions which may be primary bladder lymphomas or part of systemic lymphoma with bladder involvement. We report a case of non-Hodgkin's lymphoma (NHL in a 73-year-old female who presented with bladder tumor which on evaluation revealed NHL with extensive systemic involvement. The management of such an advanced case is discussed here with literature review.

Actualization the risks local payment systems on the present stage of the national payment system

Directory of Open Access Journals (Sweden)

Korobeinikova Olga Mikhailovna

2014-09-01

Full Text Available In the article presented and estimated systematically possibilities of minimization the general and specific risks local payment systems and their participants, which actualized due to the activation of formation of national payment system in Russia amid increasing global political and financial risks and the need for economic security.

A case of systemic lupus erythematosus presenting as bilateral avascular necrosis of femur.

Science.gov (United States)

Adikari, Madura; Gunawardane, Aloka; Illangantilaka, Sachithra; Atukorale, Himantha; Rubasinghe, Jeevanie

2016-08-05

Avascular necrosis occur as a result of diverse etiology. Chronic inflammatory conditions such as systemic lupus erythematosus considered as a recognize cause. Many cases were reported in systemic lupus erythematosus after treating with corticosteroids. We report a case of a corticosteroid naïve patient presented as bilateral avascular necrosis of femoral head and later progressed to a case of systemic lupus erythematosus. A 26 year old lady presented with right sided hip pain and diagnosed as avascular necrosis of the femoral head. After 6 months she presented a similar pain in left hip, which revealed avascular necrosis of left femoral head as well. A probable cause for her clinical presentation could not be found after extensive clinical and laboratory evaluation. Patient reported high erythrocyte sedimentation rate persistently, and over the next few years progressed as a case of systemic lupus erythematosus. Above case illustrated avascular necrosis could be an early musculoskeletal manifestation of systemic lupus erythematosus even in the absence of corticosteroid administration.

Oxidative stress responses of submerged macrophyte Vallisneria asiatica to different concentrations of cyanobacteria

Science.gov (United States)

Kang, Caixia; Kuba, Takahiro; Hao, Aimin; Iseri, Yasushi; Li, Chunjie; Zhang, Zhenjia

2015-03-01

In a 10-day aquarium experiment, this investigation examines macrophyte restoration in eutrophic Lake Taihu, the physiological effects of different plant biomass levels and of increasing natural cyanobacterial concentrations on a submerged macrophyte, Vallisneria asiatica. Cyanobacterial stress suppressed the superoxide dismutase (SOD) activity of the plant's leaves and induced the catalase (CAT) and peroxidase (POD) activities of its roots. The soluble protein content in V. asiatica decreased with an increase in natural cyanobacterial concentrations, whereas the malonaldehyde (MDA) increased significantly at chlorophyll a (Chl a) concentrations of 222 and 262 μg/L in water. V. asiatica adapted to the stress caused by cyanobacterial concentrations by adjusting its antioxidant defense system to remove the excessive reactive oxygen species when the algal Chl a concentration was >109 μg/L. Additionally, high biomass of V. asiatica (2 222 g FW/m2) can inhibit the reproduction of cyanobacteria more significantly than low biomass (1 111 g FW/m2). High biomass of V. asiatica increased the oxidative stress in an individual plant when the initial Chl a concentration in the water reached 222 and 262 μg/L, as expressed by the increased MDA in leaves, compared with low biomass of V. asiatica. This provides a basis for controlling cyanobacterial concentrations and V. asiatica biomass for the recovery of V. asiatica in eutrophic Lake Taihu.

The role of algae and cyanobacteria in the production and release of odorants in water.

Science.gov (United States)

Lee, Jechan; Rai, Prabhat Kumar; Jeon, Young Jae; Kim, Ki-Hyun; Kwon, Eilhann E

2017-08-01

This review covers literatures pertaining to algal and cyanobacterial odor problems that have been published over the last five decades. Proper evaluation of algal and cyanobacterial odors may help establish removal strategies for hazardous metabolites while enhancing the recyclability of water. A bloom of microalgae is a sign of an anthropogenic disturbance in aquatic systems and can lead to diverse changes in ecosystems along with increased production of odorants. In general, because algal and cyanobacterial odors vary in chemistry and intensity according to blooming pattern, it is necessary to learn more about the related factors and processes (e.g., changes due to differences in taxa). This necessitates systematic and transdisciplinary approaches that require the cooperation of chemists, biologists, engineers, and policy makers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Imaging findings in systemic childhood diseases presenting with dermatologic manifestations.

Science.gov (United States)

Fink, Adam Z; Gittler, Julia K; Nakrani, Radhika N; Alis, Jonathan; Blumfield, Einat; Levin, Terry L

Many childhood diseases often present with skin abnormalities with which radiologists are largely unfamiliar. Knowledge of associated dermatologic manifestations may aid the radiologist in confirming the diagnosis and recommending targeted imaging of affected organs. We review the imaging findings in childhood diseases associated with dermatologic manifestations. Diseases include dermatologic findings which herald underlying malignancy (Neuroblastoma, leukemia/lymphoma, Langerhans cell histiocytosis),are associated with risk of malignancy (Epidermolysis Bullosa, basal cell nevus syndrome, Cowden's syndrome, Tuberous Sclerosis),or indicate a systemic inflammatory/immune disorder (Kawasaki's disease, Henoch Schonlein Purpura, systemic lupus erythematosus, scleroderma, sarcoidosis, dermatomyositis and immune thrombocytopenic purpura). Familiarity with pertinent findings in childhood diseases presenting with dermatologic manifestations in childhood diseases aids the radiologist in confirming the diagnosis and guiding imaging workup. Copyright © 2017 Elsevier Inc. All rights reserved.

Operational present status and reliability analysis of the upgraded EAST cryogenic system

Science.gov (United States)

Zhou, Z. W.; Y Zhang, Q.; Lu, X. F.; Hu, L. B.; Zhu, P.

2017-12-01

Since the first commissioning in 2005, the cryogenic system for EAST (Experimental Advanced Superconducting Tokamak) has been cooled down and warmed up for thirteen experimental campaigns. In order to promote the refrigeration efficiencies and reliability, the EAST cryogenic system was upgraded gradually with new helium screw compressors and new dynamic gas bearing helium turbine expanders with eddy current brake to improve the original poor mechanical and operational performance from 2012 to 2015. Then the totally upgraded cryogenic system was put into operation in the eleventh cool-down experiment, and has been operated for the latest several experimental campaigns. The upgraded system has successfully coped with various normal operational modes during cool-down and 4.5 K steady-state operation under pulsed heat load from the tokamak as well as the abnormal fault modes including turbines protection stop. In this paper, the upgraded EAST cryogenic system including its functional analysis and new cryogenic control networks will be presented in detail. Also, its operational present status in the latest cool-down experiments will be presented and the system reliability will be analyzed, which shows a high reliability and low fault rate after upgrade. In the end, some future necessary work to meet the higher reliability requirement for future uninterrupted long-term experimental operation will also be proposed.

Present status and future development of the European Community rapid information system

International Nuclear Information System (INIS)

Fraser, G.

1990-01-01

Following the Chernobyl reactor accident it was rapidly appreciated that, in addition to upgrading national radiological monitoring systems, action was required to facilitate international communication of the results obtained. The first such system was established by the Vienna Convention, drawn up under the auspices of the IAEA, which came into force in September, 1986. Subsequently the EC Council of Ministers decided in December, 1987, to set up a Community system which in many ways parallels that established by the Convention but differs significantly in certain aspects concerning its legal basis, initiation criteria, data provisions and communications requirements. The present paper describes the present status of the Community system and foreseeable future developments. It is a matter of policy that, to avoid unnecessary complications, this system should be, to the maximum extent practicable, fully compatible with that established by the Convention. Where appropriate, therefore, reference is also made to the latter system

Present status of the TJ-II remote participation system

International Nuclear Information System (INIS)

Vega, J.; Sanchez, E.; Lopez, A.; Portas, A.; Ochando, M.; Ascasibar, E.; Mollinedo, A.; Munoz, J.; Sanchez, A.; Ruiz, M.; Barrera, E.; Lopez, S.; Castro, R.; Lopez, D.

2005-01-01

The TJ-II remote participation system (RPS) was designed to extend to Internet the working capabilities provided in the TJ-II local environment, i.e., tracking the TJ-II operation, monitoring/programming data acquisition and control systems, and accessing databases. The TJ-II RPS was based on web and Java technologies because of their open character, security properties and technological maturity. A web server acts as a communication front-end between remote participants and local TJ-II elements. From the server side, web services are provided by means of resources supplied by JSP pages. The client part makes use of web browsers and ad hoc Java applications. The operation requires the use of a distributed authentication and authorization system. This development employs the PAPI System. At present, approximately 1000 digitisation channels can be managed from the TJ-II RPS. Furthermore, processing software based on a 4GL language (LabView) can be downloaded to multiprocessor data acquisition systems. Also, 15 diagnostic control systems, databases and the operation logbook are available from the RPS. The system even allows for the physicist in charge of operation to be in a remote location. Four Spanish universities make use of the TJ-II remote participation system capabilities for joint collaborations: these are the Universidad Politecnica de Madrid (UPM), Universidad Nacional de Educacion a Distancia (UNED), Universidad Complutense de Madrid (UCM) and Universidad Politecnica de Cataluna (UPC)

GIS - Based data presentation and interactive communication system for public involvement in EIA

International Nuclear Information System (INIS)

Oprea, I.; Oprea, M.; Guta, V.; Pirvu, V.

2001-01-01

The data presentation and interactive communication system has as main task to integrate technical and administrative information, as well as to ensure an efficient public participation. The system can achieve desired inter-operability between specialists, government and public in decision-making and environmental impact assessment (EIA). It incorporates different modules relative to specific types of parameters and authorities involved. The GIS-based system provides mapping, database, automatic information collection and advanced presentation techniques. It includes a graphically oriented executive support, which has the ability to present information by geographical representation of the zones on the map. The public opinion is taking into account by consideration of alternatives and providing access to the monitoring of environmental effects. The system offers an effective way to avoid negative reactions by interactive communication based on real-time information exchange. The system can be integrated into national or international management systems, being a useful tool for an efficient communication, handling and exchanging a vast amount of information. (authors)

Estimating the risk of cyanobacterial occurrence using an index integrating meteorological factors: application to drinking water production.

Science.gov (United States)

Ndong, Mouhamed; Bird, David; Nguyen-Quang, Tri; de Boutray, Marie-Laure; Zamyadi, Arash; Vinçon-Leite, Brigitte; Lemaire, Bruno J; Prévost, Michèle; Dorner, Sarah

2014-06-01

The sudden appearance of toxic cyanobacteria (CB) blooms is still largely unpredictable in waters worldwide. Many post-hoc explanations for CB bloom occurrence relating to physical and biochemical conditions in lakes have been developed. As potentially toxic CB can accumulate in drinking water treatment plants and disrupt water treatment, there is a need for water treatment operators to determine whether conditions are favourable for the proliferation and accumulation of CB in source waters in order to adjust drinking water treatment accordingly. Thus, a new methodology with locally adaptable variables is proposed in order to have a single index, f(p), related to various environmental factors such as temperature, wind speed and direction. The index is used in conjunction with real time monitoring data to determine the probability of CB occurrence in relation to meteorological factors, and was tested at a drinking water intake in Missisquoi Bay, a shallow transboundary bay in Lake Champlain, Québec, Canada. These environmental factors alone were able to explain a maximum probability of 68% that a CB bloom would occur at the drinking water treatment plant. Nutrient limitation also influences CB blooms and intense blooms only occurred when the dissolved inorganic nitrogen (DIN) to total phosphorus (TP) mass ratio was below 3. Additional monitoring of DIN and TP could be considered for these source waters prone to cyanobacterial blooms to determine periods of favourable growth. Real time monitoring and the use of the index could permit an adequate and timely response to CB blooms in drinking water sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Edible Cyanobacterial Genus Arthrospira: Actual State of the Art in Cultivation Methods, Genetics, and Application in Medicine

Directory of Open Access Journals (Sweden)

Magda A. Furmaniak

2017-12-01

Full Text Available The cyanobacterial genus Arthrospira appears very conserved and has been divided into five main genetic clusters on the basis of molecular taxonomy markers. Genetic studies of seven Arthrospira strains, including genome sequencing, have enabled a better understanding of those photosynthetic prokaryotes. Even though genetic manipulations have not yet been performed with success, many genomic and proteomic features such as stress adaptation, nitrogen fixation, or biofuel production have been characterized. Many of above-mentioned studies aimed to optimize the cultivation conditions. Factors like the light intensity and quality, the nitrogen source, or different modes of growth (auto-, hetero-, or mixotrophic have been studied in detail. The scaling-up of the biomass production using photobioreactors, either closed or open, was also investigated to increase the production of useful compounds. The richness of nutrients contained in the genus Arthrospira can be used for promising applications in the biomedical domain. Ingredients such as the calcium spirulan, immulina, C-phycocyanin, and γ-linolenic acid (GLA show a strong biological activity. Recently, its use in the fight against cancer cells was documented in many publications. The health-promoting action of “Spirulina” has been demonstrated in the case of cardiovascular diseases and age-related conditions. Some compounds also have potent immunomodulatory properties, promoting the growth of beneficial gut microflora, acting as antimicrobial and antiviral. Products derived from Arthrospira were shown to successfully replace biomaterial scaffolds in regenerative medicine. Supplementation with the cyanobacterium also improves the health of livestock and quality of the products of animal origin. They were also used in cosmetic preparations.

Presentation Time Concerning System-Paced Multimedia Instructions and the Superiority of Learner Pacing

Science.gov (United States)

Stiller, Klaus D.; Petzold, Kirstin; Zinnbauer, Peter

2011-01-01

The superiority of learner-paced over system-paced instructions was demonstrated in multiple experiments. In these experiments, the system-paced presentations were highly speeded, causing cognitive overload, while the learner-paced instructions allowed adjustments of the presentational flow to the learner's needs by pacing facilities, mostly…

Removal of cyanobacterial blooms in Taihu Lake using local soils II. Effective removal of Microcystis aeruginosa using local soils and sediments modified by chitosan

International Nuclear Information System (INIS)

Zou Hua; Pan Gang; Chen Hao; Yuan Xianzheng

2006-01-01

After sepiolite was modified with Fe 3+ to increase its surface charge, the initial algal removal rate increased significantly, but its Q 8h was not improved substantially at clay loadings below 0.1 g/L. Modification on netting and bridging properties of clays by either chitosan or polyacrylamide (PAM) dramatically increased flocculation (Q 8h ) of MA cells in freshwaters. Algal removal efficiencies of different solids, including Type III clays, local soils and sediments, were all improved to a similar level of >90% at a total loading of 0.011 g/L (contained 0.001 g/L chitosan) after they were modified with chitosan, making the idea of clearing up algal blooms using local soils/sediments possible. The mechanism of netting and bridging was confirmed to be the most important factor in improving the removal efficiency of cells, whereas clays also played important roles in the sedimentation of the floc. -- Chitosan modification can turn many solids, such as local clays and soils, into highly effective flocculants in removing harmful cyanobacterial blooms in freshwaters

Cyanobacteria as photosynthetic biocatalysts: a systems biology perspective.

Science.gov (United States)

Gudmundsson, Steinn; Nogales, Juan

2015-01-01

The increasing need to replace oil-based products and to address global climate change concerns has triggered considerable interest in photosynthetic microorganisms. Cyanobacteria, in particular, have great potential as biocatalysts for fuels and fine-chemicals. During the last few years the biotechnological applications of cyanobacteria have experienced an unprecedented increase and the use of these photosynthetic organisms for chemical production is becoming a tangible reality. However, the field is still immature and many concerns about the economic feasibility of the biotechnological potential of cyanobacteria remain. In this review we describe recent successes in biofuel and fine-chemical production using cyanobacteria. We discuss the role of the photosynthetic metabolism and highlight the need for systems-level metabolic optimization in order to achieve the true potential of cyanobacterial biocatalysts.

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The carbonate concretions occurring at the bottom of Talchir fissile shale facies preserved signatures of various trace fossils along with a cast of doubtful organisms and cyanobacterial mat structures. The host shale deposited under glacial melt water fed lacustrine condition.The concretions,formed in poorly oxygenated ...

Multi-mission space science data processing systems - Past, present, and future

Science.gov (United States)

Stallings, William H.

1990-01-01

Packetized telemetry that is consistent with the international Consultative Committee for Space Data Systems (CCSDS) has been baselined for future NASA missions such as Space Station Freedom. Some experiences from past and present multimission systems are examined, including current experiences in implementing a CCSDS standard packetized data processing system, relative to the effectiveness of the multimission approach in lowering life cycle cost and the complexity of meeting new mission needs. It is shown that the continued effort toward standardization of telemetry and processing support will permit the development of multimission systems needed to meet the increased requirements of future NASA missions.

Dynamics of Total Microcystin LR Concentration in Three Subtropical Hydroelectric Generation Reservoirs in Uruguay, South America.

Science.gov (United States)

González-Piana, Mauricio; Fabián, Daniel; Piccardo, Andrea; Chalar, Guillermo

2017-10-01

This study analyzed the temporal dynamics of total microcystin LR concentrations between the years of 2012 and 2015 in the Bonete, Baygorria and Palmar hydroelectric generation reservoirs in the central region of the Negro River, Uruguay. The three reservoirs showed differents total microcystin LR concentration, with no significant differences among them. Over 20 sampling dates, the three reservoirs exhibited total microcystin LR concentrations on eight occasions that corresponded to a slight to moderate human health risk according to WHO guideline values for recreational waters. By determining the concentration of microcystin LR in cyanobacterial biomass, we identified cyanobacterial populations that occurred over time with varying degrees of toxin production (maximal 85.4 µg/mm 3 ). The microcystin LR concentration in Bonete was positively correlated with temperature (r = 0.587) and cyanobacterial biomass (r = 0.736), in Baygorria with cyanobacterial biomass (r = 0.521), and in Palmar with temperature (r = 0.500) and negatively correlated with ammonia (r = -0.492). Action is needed to reduce the presence of toxic cyanobacteria in these systems. A decrease in the use of agrochemicals and management changes in the reservoir basins could be successful long-term measures.

LOFT data acquisition and visual display system (DAVDS) presentation program

International Nuclear Information System (INIS)

Bullock, M.G.; Miyasaki, F.S.

1976-03-01

The Data Acquisition and Visual Display System (DAVDS) at the Loss-of-Fluid Test Facility (LOFT) has 742 data channel recording capability of which 576 are recorded digitally. The purpose of this computer program is to graphically present the data acquired and/or processed by the LOFT DAVDS. This program takes specially created plot data buffers of up to 1024 words and generates time history plots on the system electrostatic printer-plotter. The data can be extracted from two system input devices: Magnetic disk or digital magnetic tape. Versatility has been designed in the program by providing the user three methods of scaling plots: Automatic, control record, and manual. Time required to produce a plot on the system electrostatic printer-plotter varies from 30 to 90 seconds depending on the options selected. The basic computer and program details are described

Biologically active compounds from cyanobacteria extracts: in vivo and in vitro aspects

Directory of Open Access Journals (Sweden)

Luciana R. Carvalho

2013-05-01

Full Text Available An investigation was directed towards the antiacetylcholinesterase activity of the acid aqueous and methanolic extracts of five cyanobacterial taxa, which encompasses an enzymatic inhibition essay and the evaluation of the physiological responses of mice to cyanobacterial extracts along with toxicological observations. The strains Calothrix sp. CCIBt 3320, Tolypothrix sp. CCIBt 3321, Phormidium cf. amoenum CCIBt 3412, Phormidium sp. CCIBt 3265, and Geitlerinema splendidum CCIBt 3223 were from the São Paulo Botanical Institute Cyanobacterial Culture Collection and all of them showed inhibitory effect on acetylcholinesterase activity (in vitro and caused systemic effects similar to those described for anticholinesterase drugs (in vivo. With the exception of G. splendidum and Tolypothrix sp. strains, all extracts produced reversible antiacetylcolinesterase effects in mice. Complementary histopathological studies were carried out on tissues from animals administered with Phormidium sp. and P. cf. amoenum.

Biologically active compounds from cyanobacteria extracts: in vivo and in vitro aspects

Directory of Open Access Journals (Sweden)

Luciana R. Carvalho

2013-06-01

Full Text Available An investigation was directed towards the antiacetylcholinesterase activity of the acid aqueous and methanolic extracts of five cyanobacterial taxa, which encompasses an enzymatic inhibition essay and the evaluation of the physiological responses of mice to cyanobacterial extracts along with toxicological observations. The strains Calothrix sp. CCIBt 3320, Tolypothrix sp. CCIBt 3321, Phormidium cf. amoenum CCIBt 3412, Phormidium sp. CCIBt 3265, and Geitlerinema splendidum CCIBt 3223 were from the São Paulo Botanical Institute Cyanobacterial Culture Collection and all of them showed inhibitory effect on acetylcholinesterase activity (in vitro and caused systemic effects similar to those described for anticholinesterase drugs (in vivo. With the exception of G. splendidum and Tolypothrix sp. strains, all extracts produced reversible antiacetylcolinesterase effects in mice. Complementary histopathological studies were carried out on tissues from animals administered with Phormidium sp. and P. cf. amoenum.

COMPUTER SUPPORT SYSTEMS FOR ESTIMATING CHEMICAL TOXICITY: PRESENT CAPABILITIES AND FUTURE TRENDS

Science.gov (United States)

Computer Support Systems for Estimating Chemical Toxicity: Present Capabilities and Future Trends A wide variety of computer-based artificial intelligence (AI) and decision support systems exist currently to aid in the assessment of toxicity for environmental chemicals. T...

Monitoring osseointegration and developing intelligent systems (Conference Presentation)

Science.gov (United States)

Salvino, Liming W.

2017-05-01

Effective monitoring of structural and biological systems is an extremely important research area that enables technology development for future intelligent devices, platforms, and systems. This presentation provides an overview of research efforts funded by the Office of Naval Research (ONR) to establish structural health monitoring (SHM) methodologies in the human domain. Basic science efforts are needed to utilize SHM sensing, data analysis, modeling, and algorithms to obtain the relevant physiological and biological information for human-specific health and performance conditions. This overview of current research efforts is based on the Monitoring Osseointegrated Prosthesis (MOIP) program. MOIP develops implantable and intelligent prosthetics that are directly anchored to the bone of residual limbs. Through real-time monitoring, sensing, and responding to osseointegration of bones and implants as well as interface conditions and environment, our research program aims to obtain individualized actionable information for implant failure identification, load estimation, infection mitigation and treatment, as well as healing assessment. Looking ahead to achieve ultimate goals of SHM, we seek to expand our research areas to cover monitoring human, biological and engineered systems, as well as human-machine interfaces. Examples of such include 1) brainwave monitoring and neurological control, 2) detecting and evaluating brain injuries, 3) monitoring and maximizing human-technological object teaming, and 4) closed-loop setups in which actions can be triggered automatically based on sensors, actuators, and data signatures. Finally, some ongoing and future collaborations across different disciplines for the development of knowledge automation and intelligent systems will be discussed.

75 FR 35096 - Federal Employees' Retirement System; Present Value Factors

Science.gov (United States)

2010-06-21

... by the Board of Actuaries of the Civil Service Retirement System. DATES: The revised present value.... ADDRESSES: Send requests for actuarial assumptions and data to the Board of Actuaries, care of Gregory Kissel, Actuary, Office of Planning and Policy Analysis, Office of Personnel Management, Room 4307, 1900...

Cyanobacterial Lactate Oxidases Serve as Essential Partners in N2 Fixation and Evolved into Photorespiratory Glycolate Oxidases in Plants[w

Science.gov (United States)

Hackenberg, Claudia; Kern, Ramona; Hüge, Jan; Stal, Lucas J.; Tsuji, Yoshinori; Kopka, Joachim; Shiraiwa, Yoshihiro; Bauwe, Hermann; Hagemann, Martin

2011-01-01

Glycolate oxidase (GOX) is an essential enzyme involved in photorespiratory metabolism in plants. In cyanobacteria and green algae, the corresponding reaction is catalyzed by glycolate dehydrogenases (GlcD). The genomes of N2-fixing cyanobacteria, such as Nostoc PCC 7120 and green algae, appear to harbor genes for both GlcD and GOX proteins. The GOX-like proteins from Nostoc (No-LOX) and from Chlamydomonas reinhardtii showed high l-lactate oxidase (LOX) and low GOX activities, whereas glycolate was the preferred substrate of the phylogenetically related At-GOX2 from Arabidopsis thaliana. Changing the active site of No-LOX to that of At-GOX2 by site-specific mutagenesis reversed the LOX/GOX activity ratio of No-LOX. Despite its low GOX activity, No-LOX overexpression decreased the accumulation of toxic glycolate in a cyanobacterial photorespiratory mutant and restored its ability to grow in air. A LOX-deficient Nostoc mutant grew normally in nitrate-containing medium but died under N2-fixing conditions. Cultivation under low oxygen rescued this lethal phenotype, indicating that N2 fixation was more sensitive to O2 in the Δlox Nostoc mutant than in the wild type. We propose that LOX primarily serves as an O2-scavenging enzyme to protect nitrogenase in extant N2-fixing cyanobacteria, whereas in plants it has evolved into GOX, responsible for glycolate oxidation during photorespiration. PMID:21828292

76 FR 32243 - Federal Employees' Retirement System; Present Value Factors

Science.gov (United States)

2011-06-03

... adopted by the Board of Actuaries of the Civil Service Retirement System. DATES: The revised present value.... ADDRESSES: Send requests for actuarial assumptions and data to the Board of Actuaries, care of Gregory Kissel, Actuary, Office of Planning and Policy Analysis, Office of Personnel Management, Room 4307, 1900...

The effect of sulfate concentration on (sub)millimeter-scale sulfide δ 34S in hypersaline cyanobacterial mats over the diurnal cycle

Science.gov (United States)

Fike, David A.; Finke, Niko; Zha, Jessica; Blake, Garrett; Hoehler, Tori M.; Orphan, Victoria J.

2009-10-01

Substantial isotopic fractionations are associated with many microbial sulfur metabolisms and measurements of the bulk δ 34S isotopic composition of sulfur species (predominantly sulfates and/or sulfides) have been a key component in developing our understanding of both modern and ancient biogeochemical cycling. However, the interpretations of bulk δ 34S measurements are often non-unique, making reconstructions of paleoenvironmental conditions or microbial ecology challenging. In particular, the link between the μm-scale microbial activity that generates isotopic signatures and their eventual preservation as a bulk rock value in the geologic record has remained elusive, in large part because of the difficulty of extracting sufficient material at small scales. Here we investigate the potential for small-scale (˜100 μm-1 cm) δ 34S variability to provide additional constraints for environmental and/or ecological reconstructions. We have investigated the impact of sulfate concentrations (0.2, 1, and 80 mM SO 4) on the δ 34S composition of hydrogen sulfide produced over the diurnal (day/night) cycle in cyanobacterial mats from Guerrero Negro, Baja California Sur, Mexico. Sulfide was captured as silver sulfide on the surface of a 2.5 cm metallic silver disk partially submerged beneath the mat surface. Subsequent analyses were conducted on a Cameca 7f-GEO secondary ion mass spectrometer (SIMS) to record spatial δ 34S variability within the mats under different environmental conditions. Isotope measurements were made in a 2-dimensional grid for each incubation, documenting both lateral and vertical isotopic variation within the mats. Typical grids consisted of ˜400-800 individual measurements covering a lateral distance of ˜1 mm and a vertical depth of ˜5-15 mm. There is a large isotopic enrichment (˜10-20‰) in the uppermost mm of sulfide in those mats where [SO 4] was non-limiting (field and lab incubations at 80 mM). This is attributed to rapid recycling of

The importance of extremophile cyanobacteria in the production of biologically active compounds

Directory of Open Access Journals (Sweden)

Drobac-Čik Aleksandra V.

2007-01-01

Full Text Available Due to their ability to endure extreme conditions, terrestrial cyanobacteria belong to a group of organisms known as "extremophiles". Research so far has shown that these organisms posses a great capacity for producing biologically active compounds (BAC. The antibacterial and antifungal activities of methanol extracts of 21 cyanobacterial strains belonging to Anabaena and Nostoc genera, previously isolated from different soil types and water resources in Serbia, were evaluated. In general, larger number of cyanobacterial strains showed antifungal activity. In contrast to Nostoc, Anabaena strains showed greater diversity of antibacterial activity (mean value of percentages of sensitive targeted bacterial strains 3% and 25.9% respectively. Larger number of targeted fungi was sensitive to cultural liquid extract (CL, while crude cell extract (CE affected more bacterial strains. According to this investigation, the higher biological activity of terrestrial strains as representatives of extremophiles may present them as significant BAC producers. This kind of investigation creates very general view of cyanobacterial possibility to produce biologically active compounds but it points out the necessity of exploring terrestrial cyanobacterial extremophiles as potentially excellent sources of these substances and reveals the most prospective strains for further investigations.

Present status and problems of remote systems technology in nuclear industry

Energy Technology Data Exchange (ETDEWEB)

1989-02-01

This reports the activities of Special Committee on Remote Systems Technology, Atomic Energy Society of Japan, during the period from Oct. 1984 to Sep. 1988. The Committee studied and reviewed the present status and problems of remote operation and maintenance in various fields of nuclear industry. Reported items are; reactor operation, reprocessing, nuclear fusion and decommissioning. It also reviews robotics and remote systems tehcnology applied to space and marine development.

Present status and problems of remote systems technology in nuclear industry

International Nuclear Information System (INIS)

1989-01-01

This reports the activities of Special Committee on Remote Systems Technology, Atomic Energy Society of Japan, during the period from Oct. 1984 to Sep. 1988. The Committee studied and reviewed the present status and problems of remote operation and maintenance in various fields of nuclear industry. Reported items are; reactor operation, reprocessing, nuclear fusion and decommissioning. It also reviews robotics and remote systems tehcnology applied to space and marine development. (author)

Behavioral Risk Factor Surveillance System (BRFSS) Prevalence Data (2011 to present)

Data.gov (United States)

U.S. Department of Health & Human Services — 2011 to present. BRFSS combined land line and cell phone prevalence data. BRFSS is a continuous, state-based surveillance system that collects information about...

ANAPHYLACTOID SHOCK FOLLOWING HYMENOPTERA STING AS A PRESENTING SYMPTOM OF SYSTEMIC MASTOCYTOSIS

NARCIS (Netherlands)

KORS, JW; VANDOORMAAL, JJ; DEMONCHY, JGR

Systemic mastocytosis is a rare and chronic disorder characterized by a pathologically increased number of mast cells in various tissues and overproduction of mast cell mediators. From a group of 1 5 patients (I 0 females, 5 males) with systemic mastocytosis five female patients presented with a

Central nervous system lymphoma: magnetic resonance imaging features at presentation

Directory of Open Access Journals (Sweden)

Ricardo Schwingel

2012-02-01

Full Text Available OBJECTIVE: This paper aimed at studying presentations of the central nervous system (CNS lymphoma using structural images obtained by magnetic resonance imaging (MRI. METHODS: The MRI features at presentation of 15 patients diagnosed with CNS lymphoma in a university hospital, between January 1999 and March 2011, were analyzed by frequency and cross tabulation. RESULTS: All patients had supratentorial lesions; and four had infra- and supratentorial lesions. The signal intensity on T1 and T2 weighted images was predominantly hypo- or isointense. In the T2 weighted images, single lesions were associated with a hypointense signal component. Six patients presented necrosis, all of them showed perilesional abnormal white matter, nine had meningeal involvement, and five had subependymal spread. Subependymal spread and meningeal involvement tended to occur in younger patients. CONCLUSION: Presentations of lymphoma are very pleomorphic, but some of them should point to this diagnostic possibility.

Development of SMES for power system control: present status and perspective

International Nuclear Information System (INIS)

Ohsaki, H.; Taniguchi, S.; Nagaya, S.; Akita, S.; Koso, S.; Tatsuta, M.

2004-01-01

A present Japanese national project for SMES development focuses on the development of cost reduction technologies for a small-scale SMES for power system control. Optimal SMES system concepts were developed for power system stabilization and for load fluctuation compensation or frequency regulation. Performance of the designed superconductors was analyzed through fabrication and tests of short sample superconductors. Then, two kinds of model coil systems were manufactured and tested for evaluation of the design concepts and cost reduction technology developments. A multi-pole solenoid coil set as a model coil system for load fluctuation compensation SMES was successfully tested, for example, in 10 000-pulse iterative charge-discharge operations. In addition, application of high-T C superconductors to SMES has been studied for further cost reduction, more reliable operation, etc

The FODA-TDMA satellite access scheme - Presentation, study of the system, and results

Science.gov (United States)

Celandroni, Nedo; Ferro, Erina

1991-12-01

A description is given of FODA-TDMA, a satellite access scheme designed for mixed traffic. The study of the system is presented and the choice of some parameters is justified. A simplified analytic solution is found, describing the steady-state behavior of the system. Some results of the simulation tests for an already existing hardware environment are also presented for the channel speeds of 2 and 8 Mb/s, considering both the stationary and the transient cases. The results of the experimentation at 2 Mb/s on the satellite Eutelsat-F2 are also presented and compared with the results of the simulation.

The Anabaena sp. PCC 7120 Exoproteome: Taking a Peek outside the Box

Directory of Open Access Journals (Sweden)

Paulo Oliveira

2015-01-01

Full Text Available The interest in examining the subset of proteins present in the extracellular milieu, the exoproteome, has been growing due to novel insights highlighting their role on extracellular matrix organization and biofilm formation, but also on homeostasis and development. The cyanobacterial exoproteome is poorly studied, and the role of cyanobacterial exoproteins on cell wall biogenesis, morphology and even physiology is largely unknown. Here, we present a comprehensive examination of the Anabaena sp. PCC 7120 exoproteome under various growth conditions. Altogether, 139 proteins belonging to 16 different functional categories have been identified. A large fraction (48% of the identified proteins is classified as “hypothetical”, falls into the “other categories” set or presents no similarity to other proteins. The evidence presented here shows that Anabaena sp. PCC 7120 is capable of outer membrane vesicle formation and that these vesicles are likely to contribute to the exoproteome profile. Furthermore, the activity of selected exoproteins associated with oxidative stress has been assessed, suggesting their involvement in redox homeostasis mechanisms in the extracellular space. Finally, we discuss our results in light of other cyanobacterial exoproteome studies and focus on the potential of exploring cyanobacteria as cell factories to produce and secrete selected proteins.

N:P ratios, light limitation, and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution

International Nuclear Information System (INIS)

Havens, K.E.; James, R.T.; East, T.L.; Smith, V.H.

2003-01-01

Low ratios of N:P and low underwater irradiance control dominance of cyanobacteria in a subtropical lake. - A long-term (28-year) data set was used to investigate historical changes in concentrations of phosphorus (P), nitrogen (N), N:P ratios, and Secchi disk transparency in a shallow subtropical lake (Lake Okeechobee, Florida, USA). The aim was to evaluate changes in the risk of N 2 -fixing cyanobacterial blooms, which have infrequently occurred in the lake's pelagic zone. Predictions regarding bloom risk were based on previously published N:P ratio models. Temporal trends in the biomass of cyanobacteria were evaluated using phytoplankton data collected in 1974, 1989-1992, and 1997-2000. Concentrations of pelagic total P increased from near 50 μg l -1 in the mid-1970s to over 100 μg l -1 in the late 1990s. Coincidentally, the total N:P (mass) ratio decreased from 30:1 to below 15:1, and soluble N:P ratio decreased from 15:1 to near 6:1, in the lake water. Published empirical models predict that current conditions favor cyanobacteria. The observations confirm this prediction: cyanobacteria presently account for 50-80% of total phytoplankton biovolume. The historical decrease in TN:TP ratio in the lake can be attributed to a decreased TN:TP ratio in the inflow water and to a decline in the lake's assimilation of P, relative to N. Coincident with these declines in total and soluble N:P ratios, Secchi disk transparency declined from 0.6 m to near 0.3 m, possibly due to increased mineral turbidity in the lake water. Empirical models predict that under the turbid, low irradiance conditions that prevail in this lake, non-heterocystous cyanobacteria should dominate the phytoplankton. Our observations confirmed this prediction: non-N 2 -fixing taxa (primarily Oscillatoria and Lyngbya spp.) typically dominated the cyanobacteria community during the last decade. The only exception was a year with very low water levels, when heterocystous N 2 -fixing Anabaena became

N:P ratios, light limitation, and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution.

Science.gov (United States)

Havens, Karl E; James, R Thomas; East, Therese L; Smith, Val H

2003-01-01

A long-term (28-year) data set was used to investigate historical changes in concentrations of phosphorus (P), nitrogen (N), N:P ratios, and Secchi disk transparency in a shallow subtropical lake (Lake Okeechobee, Florida, USA). The aim was to evaluate changes in the risk of N2-fixing cyanobacterial blooms, which have infrequently occurred in the lake's pelagic zone. Predictions regarding bloom risk were based on previously published N:P ratio models. Temporal trends in the biomass of cyanobacteria were evaluated using phytoplankton data collected in 1974, 1989-1992, and 1997-2000. Concentrations of pelagic total P increased from near 50 microg l-1 in the mid-1970s to over 100 microg l-1 in the late 1990s. Coincidentally, the total N:P (mass) ratio decreased from 30:1 to below 15:1, and soluble N:P ratio decreased from 15:1 to near 6:1, in the lake water. Published empirical models predict that current conditions favor cyanobacteria. The observations confirm this prediction: cyanobacteria presently account for 50-80% of total phytoplankton biovolume. The historical decrease in TN:TP ratio in the lake can be attributed to a decreased TN:TP ratio in the inflow water and to a decline in the lake's assimilation of P, relative to N. Coincident with these declines in total and soluble N:P ratios, Secchi disk transparency declined from 0.6 m to near 0.3 m, possibly due to increased mineral turbidity in the lake water. Empirical models predict that under the turbid, low irradiance conditions that prevail in this lake, non-heterocystous cyanobacteria should dominate the phytoplankton. Our observations confirmed this prediction: non-N2-fixing taxa (primarily Oscillatoria and Lyngbya spp.) typically dominated the cyanobacteria community during the last decade. The only exception was a year with very low water levels, when heterocystous N2-fixing Anabaena became dominant. In the near-shore regions of this shallow lake, low N:P ratios potentially favor blooms of N2-fixing

The Online Histogram Presenter for the ATLAS experiment: A modular system for histogram visualization

International Nuclear Information System (INIS)

Dotti, Andrea; Adragna, Paolo; Vitillo, Roberto A

2010-01-01

The Online Histogram Presenter (OHP) is the ATLAS tool to display histograms produced by the online monitoring system. In spite of the name, the Online Histogram Presenter is much more than just a histogram display. To cope with the large amount of data, the application has been designed to minimise the network traffic; sophisticated caching, hashing and filtering algorithms reduce memory and CPU usage. The system uses Qt and ROOT for histogram visualisation and manipulation. In addition, histogram visualisation can be extensively customised through configuration files. Finally, its very modular architecture features a lightweight plug-in system, allowing extensions to accommodate specific user needs. After an architectural overview of the application, the paper is going to present in detail the solutions adopted to increase the performance and a description of the plug-in system.

The Online Histogram Presenter for the ATLAS experiment: A modular system for histogram visualization

Energy Technology Data Exchange (ETDEWEB)

Dotti, Andrea [CERN, CH-1211 Genve 23 Switzerland (Switzerland); Adragna, Paolo [Physics Department, Queen Mary, University of London Mile End Road London E1 4RP UK (United Kingdom); Vitillo, Roberto A, E-mail: andrea.dotti@cern.c [INFN Sezione di Pisa, Ed. C Largo Bruno Pontecorvo 3, 56127 Pisa (Italy)

2010-04-01

The Online Histogram Presenter (OHP) is the ATLAS tool to display histograms produced by the online monitoring system. In spite of the name, the Online Histogram Presenter is much more than just a histogram display. To cope with the large amount of data, the application has been designed to minimise the network traffic; sophisticated caching, hashing and filtering algorithms reduce memory and CPU usage. The system uses Qt and ROOT for histogram visualisation and manipulation. In addition, histogram visualisation can be extensively customised through configuration files. Finally, its very modular architecture features a lightweight plug-in system, allowing extensions to accommodate specific user needs. After an architectural overview of the application, the paper is going to present in detail the solutions adopted to increase the performance and a description of the plug-in system.

Present status and issues for accelerator driven transmutation system

International Nuclear Information System (INIS)

Mizumoto, Motoharu

2003-01-01

Proper treatment of high-level nuclear wastes (HLW) that are produced in operation of nuclear power plants is one of the most important problems for further utilization of nuclear energy. The purpose of the accelerator driven nuclear waste transmutation system (ADS) is to transmute these nuclei to stable or short-lived nuclei by various radiation-induced nuclear reactions. When ADS for HLW can be realized, burden to deep geological disposal can be considerably reduced. In the paper, present status and issues for ADS will be discussed. (author)

Environmental factors that influence cyanobacteria and geosmin occurrence in reservoirs

Science.gov (United States)

Journey, Celeste A.; Beaulieu, Karen M.; Bradley, Paul M.; Bradley, Paul M.

2013-01-01

Phytoplankton are small to microscopic, free-floating algae that inhabit the open water of freshwater, estuarine, and saltwater systems. In freshwater lake and reservoirs systems, which are the focus of this chapter, phytoplankton communities commonly consist of assemblages of the major taxonomic groups, including green algae, diatoms, dinoflagellates, and cyanobacteria. Cyanobacteria are a diverse group of single-celled organisms that can exist in a wide range of environments, not just open water, because of their adaptability. It is the adaptability of cyanobacteria that enables this group to dominate the phytoplankton community and even form nuisance or harmful blooms under certain environmental conditions. In fact, cyanobacteria are predicted to adapt favorably to future climate change in freshwater systems compared to other phytoplankton groups because of their tolerance to rising temperatures, enhanced vertical thermal stratification of aquatic ecosystems, and alterations in seasonal and interannual weather patterns. Understanding those environmental conditions that favor cyanobacterial dominance and bloom formation has been the focus of research throughout the world because of the concomitant production and release of nuisance and toxic cyanobacterial-derived compounds. However, the complex interaction among the physical, chemical, and biological processes within lakes, reservoirs, and large rivers often makes it difficult to identify primary environmental factors that cause the production and release of these cyanobacterial by-products.

System to determine present elements in oily samples

International Nuclear Information System (INIS)

Mendoza G, Y.

2004-11-01

In the Chemistry Department of the National Institute of Nuclear Investigations of Mexico, dedicated to analyze samples of oleaginous material and of another origin, to determine the elements of the periodic table present in the samples, through the Neutron activation analysis technique (NAA). This technique has been developed to determine majority elements in any solid, aqueous, industrial and environmental sample, which consists basically on to irradiate a sample with neutrons coming from the TRIGA Mark III reactor and to carry out the analysis to obtain those gamma spectra that it emits, for finally to process the information, the quantification of the analysis it is carried out in a manual way, which requires to carry out a great quantity of calculations. The main objective of this project is the development of a software that allows to carry out the quantitative analysis of the NAA for the multielemental determination of samples in an automatic way. To fulfill the objective of this project it has been divided in four chapters: In the first chapter it is shortly presented the history on radioactivity and basic concepts that will allow us penetrate better to this work. In the second chapter the NAA is explained which is used in the sample analysis, the description of the process to be carried out, its are mentioned the characteristics of the used devices and an example of the process is illustrated. In the third chapter it is described the development of the algorithm and the selection of the programming language. The fourth chapter it is shown the structure of the system, the general form of operation, the execution of processes and the obtention of results. Later on the launched results are presented in the development of the present project. (Author)

Front end embedded microprocessors in the JET computer-based control system, past, present and future

International Nuclear Information System (INIS)

Steed, C.A.; VanderBeken, H.; Browne, M.L.; Fullard, K.; Reed, K.; Tilley, M.; Schmidt, V.

1987-01-01

A brief history of the use of Front End Microprocessors in the JET Control and Data Acquisition System (CODAS) is presented. The present expansion in their use from 2 or 3 in 1983 to 27 now, is covered along with the reasoning behind their present usage. Finally, their future planned use in the area of remote handling is discussed and the authors present views on the use of front end processing in future large distributed control systems are presented

Cyanobacteria-mediated phenylpropanoids and phytohormones in rice (Oryza sativa) enhance plant growth and stress tolerance.

Science.gov (United States)

Singh, Dhananjaya P; Prabha, Ratna; Yandigeri, Mahesh S; Arora, Dilip K

2011-11-01

Phenylpropanoids, flavonoids and plant growth regulators in rice (Oryza sativa) variety (UPR 1823) inoculated with different cyanobacterial strains namely Anabaena oryzae, Anabaena doliolum, Phormidium fragile, Calothrix geitonos, Hapalosiphon intricatus, Aulosira fertilissima, Tolypothrix tenuis, Oscillatoria acuta and Plectonema boryanum were quantified using HPLC in pot conditions after 15 and 30 days. Qualitative analysis of the induced compounds using reverse phase HPLC and further confirmation with LC-MS/MS showed consistent accumulation of phenolic acids (gallic, gentisic, caffeic, chlorogenic and ferulic acids), flavonoids (rutin and quercetin) and phytohormones (indole acetic acid and indole butyric acid) in rice leaves. Plant growth promotion (shoot, root length and biomass) was positively correlated with total protein and chlorophyll content of leaves. Enzyme activity of peroxidase and phenylalanine ammonia lyase and total phenolic content was fairly high in rice leaves inoculated with O. acuta and P. boryanum after 30 days. Differential systemic accumulation of phenylpropanoids in plant leaves led us to conclude that cyanobacterial inoculation correlates positively with plant growth promotion and stress tolerance in rice. Furthermore, the study helped in deciphering possible mechanisms underlying plant growth promotion and stress tolerance in rice following cyanobacterial inoculation and indicated the less explored avenue of cyanobacterial colonization in stress tolerance against abiotic stress.

PipY, a Member of the Conserved COG0325 Family of PLP-Binding Proteins, Expands the Cyanobacterial Nitrogen Regulatory Network

Directory of Open Access Journals (Sweden)

José I. Labella

2017-07-01

Full Text Available Synechococcus elongatus PCC 7942 is a paradigmatic model organism for nitrogen regulation in cyanobacteria. Expression of genes involved in nitrogen assimilation is positively regulated by the 2-oxoglutarate receptor and global transcriptional regulator NtcA. Maximal activation requires the subsequent binding of the co-activator PipX. PII, a protein found in all three domains of life as an integrator of signals of the nitrogen and carbon balance, binds to PipX to counteract NtcA activity at low 2-oxoglutarate levels. PII-PipX complexes can also bind to the transcriptional regulator PlmA, whose regulon remains unknown. Here we expand the nitrogen regulatory network to PipY, encoded by the bicistronic operon pipXY in S. elongatus. Work with PipY, the cyanobacterial member of the widespread family of COG0325 proteins, confirms the conserved roles in vitamin B6 and amino/keto acid homeostasis and reveals new PLP-related phenotypes, including sensitivity to antibiotics targeting essential PLP-holoenzymes or synthetic lethality with cysK. In addition, the related phenotypes of pipY and pipX mutants are consistent with genetic interactions in the contexts of survival to PLP-targeting antibiotics and transcriptional regulation. We also showed that PipY overexpression increased the length of S. elongatus cells. Taken together, our results support a universal regulatory role for COG0325 proteins, paving the way to a better understanding of these proteins and of their connections with other biological processes.

Cyanobacterial diversity and related sedimentary facies as a function of water flow conditions: Example from the Monasterio de Piedra Natural Park (Spain)

Science.gov (United States)

Berrendero, Esther; Arenas, Concha; Mateo, Pilar; Jones, Brian

2016-05-01

The River Piedra in the Monasterio de Piedra Natural Park (NE Spain) is a modern tufa-depositing river that encompasses various depositional environments that are inhabited by different cyanobacterial populations. Molecular (16S rDNA) and morphological analyses of the cyanobacteria from different facies showed that Phormidium incrustatum dominates in the fast-flowing water areas where the mean depositional rate is 1.6 cm/year. Stromatolites in these areas are formed of palisades of hollow calcite tubes (inner diameter of 6.0-7.5 μm, walls 2-12 μm thick) that formed through calcite encrustation around the filaments followed by decay of the trichomes. In contrast, in slow-flowing water areas with lower depositional rates (mean depositional rate of 0.3 cm/year), Phormidium aerugineo-caeruleum is the dominant species. In these areas, randomly oriented calcite tubes (inner diameter of 5-6 μm, walls 3-8 μm thick) formed by calcite encrustation, are found in thin and uneven laminae and as scattered tubes in the loose lime mud and sand-sized carbonate sediment. Although this species did not build laminated deposits, it gave cohesiveness to the loose sediment. In the stepped and low waterfalls, with intermediate deposition rates (mean depositional rate of 0.9 cm/year), both species of Phormidium are found in association with spongy moss and algal boundstones, which is consistent with the variable flow conditions in this setting. The calcite encrustations on the cyanobacteria from different environments exhibit irregular patterns that may be linked to changes in the calcite saturation index. The physicochemical conditions associated with extracellular polymeric substances may be more significant to CaCO3 precipitation in microbial mats in slow-flowing water conditions than in fast-flowing water conditions. These results show that flow conditions may influence the distribution of different cyanobacteria that, in turn, leads to the development of different sedimentary

Strategic Planning and Decision Analysis: Presentation of the COSIMA Software System

DEFF Research Database (Denmark)

This paper presents a composite decision support system, COSIMA, programmed in MS Excel. COSIMA provides assistance to the decision maker as concerns complex decisions and strategic planning. The COSIMA software is designed as interconnected modules which make it possible to conduct Cost-Benefit...

Screen-Capturing System with Two-Layer Display for PowerPoint Presentation to Enhance Classroom Education

Science.gov (United States)

Lai, Yen-Shou; Tsai, Hung-Hsu; Yu, Pao-Ta

2011-01-01

This paper proposes a new presentation system integrating a Microsoft PowerPoint presentation in a two-layer method, called the TL system, to promote learning in a physical classroom. With the TL system, teachers can readily control hints or annotations as a way of making them visible or invisible to students so as to reduce information load. In…

Engineering cyanobacteria to generate high-value products.

Science.gov (United States)

Ducat, Daniel C; Way, Jeffrey C; Silver, Pamela A

2011-02-01

Although many microorganisms have been used for the bioindustrial generation of valuable metabolites, the productive potential of cyanobacterial species has remained largely unexplored. Cyanobacteria possess several advantages as organisms for bioindustrial processes, including simple input requirements, tolerance of marginal agricultural environments, rapid genetics, and carbon-neutral applications that could be leveraged to address global climate change concerns. Here, we review recent research involving the engineering of cyanobacterial species for the production of valuable bioindustrial compounds, including natural cyanobacterial products (e.g. sugars and isoprene), biofuels (e.g. alcohols, alkanes and hydrogen), and other commodity chemicals. Biological and economic obstacles to scaled cyanobacterial production are highlighted, and methods for increasing cyanobacterial production efficiencies are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Proteomic Analysis of Metabolic Responses to Biofuels and Chemicals in Photosynthetic Cyanobacteria.

Science.gov (United States)

Sun, T; Chen, L; Zhang, W

2017-01-01

Recent progresses in various "omics" technologies have enabled quantitative measurements of biological molecules in a high-throughput manner. Among them, high-throughput proteomics is a rapidly advancing field that offers a new means to quantify metabolic changes at protein level, which has significantly facilitated our understanding of cellular process, such as protein synthesis, posttranslational modifications, and degradation in responding to environmental perturbations. Cyanobacteria are autotrophic prokaryotes that can perform oxygenic photosynthesis and have recently attracted significant attentions as one promising alternative to traditionally biomass-based "microbial cell factories" to produce green fuels and chemicals. However, early studies have shown that the low tolerance to toxic biofuels and chemicals represented one major hurdle for further improving productivity of the cyanobacterial production systems. To address the issue, metabolic responses and their regulation of cyanobacterial cells to toxic end-products need to be defined. In this chapter, we discuss recent progresses in interpreting cyanobacterial responses to biofuels and chemicals using high-throughput proteomics approach, aiming to provide insights and guidelines on how to enhance tolerance and productivity of biofuels or chemicals in the renewable cyanobacteria systems in the future. © 2017 Elsevier Inc. All rights reserved.

Self-organization in Complex Systems The Past, Present, and Future of Synergetics : International Symposium

CERN Document Server

Pelster, Axel

2016-01-01

This proceedings volume contains talks and poster presentations from the International Symposium "Self-Organization in Complex Systems: The Past, Present, and Future of Synergetics", which took place at Hanse-Wissenschaftskolleg, an Institute of Advanced Studies, in Delmenhorst, Germany, during the period November 13 - 16, 2012. The Symposium was organized in honour of Hermann Haken, who celebrated his 85th birthday in 2012. With his fundamental theory of Synergetics he had laid the mathematical-physical basis for describing and analyzing self-organization processes in a diversity of fields of research. The quest for common and universal principles of self-organization in complex systems was clearly covered by the wide range of interdisciplinary topics reported during the Symposium. These extended from complexity in classical systems and quantum systems over self-organisation in neuroscience even to the physics of finance. Moreover, by combining a historical view with a present status report the Symposium con...

Improved Fab presentation on phage surface with the use of molecular chaperone coplasmid system.

Science.gov (United States)

Loh, Qiuting; Leong, Siew Wen; Tye, Gee Jun; Choong, Yee Siew; Lim, Theam Soon

2015-05-15

The low presentation efficiency of Fab (fragment antigen binding) fragments during phage display is largely due to the complexity of disulphide bond formation. This can result in the presentation of Fab fragments devoid of a light chain during phage display. Here we propose the use of a coplasmid system encoding several molecular chaperones (DsbA, DsbC, FkpA, and SurA) to improve Fab packaging. A comparison was done using the Fab fragment from IgG and IgD. We found that the use of the coplasmid during phage packaging was able to improve the presentation efficiency of the Fab fragment on phage surfaces. A modified version of panning using the coplasmid system was evaluated and was successful at enriching Fab binders. Therefore, the coplasmid system would be an attractive alternative for improved Fab presentation for phage display. Copyright © 2015 Elsevier Inc. All rights reserved.

Oil-Free Shaft Support System Rotordynamics: Past, Present, and Future Challenges and Opportunities

Science.gov (United States)

DellaCorte, Christopher

2011-01-01

Recent breakthroughs in Oil-Free technologies have enabled new high-speed rotor systems and turbomachinery. Such technologies can include compliant-surface gas bearings, magnetic bearings, and advanced solid lubricants and tribo-materials. This presentation briefly reviews critical technology developments and the current state-of-the-art, emerging Oil-Free rotor systems and discusses obstacles preventing more widespread use. Key examples of "best practices" for deploying Oil-Free technologies will be presented and remaining major technical questions surrounding Oil-Free technologies will be brought forward.

Texosome-based drug delivery system for cancer therapy: from past to present

International Nuclear Information System (INIS)

Mahmoodzadeh Hosseini, Hamideh; Halabian, Raheleh; Amin, Mohsen; Imani Fooladi, Abbas Ali

2015-01-01

Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor microenvironment, causes tumor growth and enhances tumor progression. Thus, cancer immunotherapy can be an appropriate approach to provoke the systemic immune system to combat tumor expansion. Texosomes, which are endogenous nanovesicles released by all tumor cells, contribute to cell-cell communication and modify the phenotypic features of recipient cells due to the texosomes’ ability to transport biological components. For this reason, texosome-based delivery system can be a valuable strategy for therapeutic purposes. To improve the pharmaceutical behavior of this system and to facilitate its use in medical applications, biotechnology approaches and mimetic techniques have been utilized. In this review, we present the development history of texosome-based delivery systems and discuss the advantages and disadvantages of each system

Android application and REST server system for quasar spectrum presentation and analysis

Science.gov (United States)

Wasiewicz, P.; Pietralik, K.; Hryniewicz, K.

2017-08-01

This paper describes the implementation of a system consisting of a mobile application and RESTful architecture server intended for the analysis and presentation of quasars' spectrum. It also depicts the quasar's characteristics and significance to the scientific community, the source for acquiring astronomical objects' spectral data, used software solutions as well as presents the aspect of Cloud Computing and various possible deployment configurations.

Assessment of present and future large-scale semiconductor detector systems

International Nuclear Information System (INIS)

Spieler, H.G.; Haller, E.E.

1984-11-01

The performance of large-scale semiconductor detector systems is assessed with respect to their theoretical potential and to the practical limitations imposed by processing techniques, readout electronics and radiation damage. In addition to devices which detect reaction products directly, the analysis includes photodetectors for scintillator arrays. Beyond present technology we also examine currently evolving structures and techniques which show potential for producing practical devices in the foreseeable future

Detection of the cyanobacterial hepatotoxins microcystins

International Nuclear Information System (INIS)

McElhiney, Jacqui; Lawton, Linda A.

2005-01-01

Concern regarding the presence of microcystins in drinking water and their possible contamination in food (e.g., salad vegetables, fish, shellfish) has resulted in the need for reliable methods for the detection and accurate quantification of this class of toxins. Currently, routine analysis of microcystins is most commonly carried out using high-performance liquid chromatography with photodiode array detection (HPLC-PDA), although more sensitive biological assays such as antibody-based ELISAs and protein phosphatase inhibition assays have also proven useful. However, many of these methods have been hindered by the availability of a wide range of purified microcystins. Although over 60 variants have now been reported, only a very small number are commercially available and calibrated standards are not yet obtainable. This has led to the common practice of reporting microcystin-LR equivalence regardless of which variant is present. The increased availability of HPLC with online mass spectral analysis (HPLC-MS) may facilitate more accurate detection of toxin variants but as several microcystins share the same molecular mass, definitive identification can be difficult. A further difficulty in analyzing microcystins is the requirement for sample processing before analysis. Solid phase extraction (SPE) is typically used to enrich environmental concentrations of microcystins, or to eliminate contaminants from complex samples such as animal and plant tissues. Recently, new technologies employing recombinant antibodies and molecularly imprinted polymers have been exploited to develop assays and biosensors for microcystins. These novel detection systems are highly sensitive, often do not require sample processing, and offer a simpler, less expensive alternative to analytical techniques. They have also been successfully employed in solid phase extraction formats for the concentration and clean up of environmental samples before HPLC analysis

Rapid Isolation of a Single-Chain Antibody against the Cyanobacterial Toxin Microcystin-LR by Phage Display and Its Use in the Immunoaffinity Concentration of Microcystins from Water

Science.gov (United States)

McElhiney, Jacqui; Drever, Mathew; Lawton, Linda A.; Porter, Andy J.

2002-01-01

A naïve (unimmunized) human semisynthetic phage display library was employed to isolate recombinant antibody fragments against the cyanobacterial hepatotoxin microcystin-LR. Selected antibody scFv genes were cloned into a soluble expression vector and expressed in Escherichia coli for characterization against purified microcystin-LR by competition enzyme-linked immunosorbent assay (ELISA). The most sensitive single-chain antibody (scAb) isolated was capable of detecting microcystin-LR at levels below the World Health Organization limit in drinking water (1 μg liter−1) and cross-reacted with three other purified microcystin variants (microcystin-RR, -LW, and -LF) and the related cyanotoxin nodularin. Extracts of the cyanobacterium Microcystis aeruginosa were assayed by ELISA, and quantifications of microcystins in toxic samples showed good correlation with analysis by high-performance liquid chromatography. Immobilized scAb was also used to prepare immunoaffinity columns, which were assessed for the ability to concentrate microcystin-LR from water for subsequent analysis by high-performance liquid chromatography. Anti-microcystin-LR scAb was immobilized on columns via a hexahistidine tag, ensuring maximum exposure of antigen binding sites, and the performance of the columns was evaluated by directly applying 150 ml of distilled water spiked with 4 μg of purified microcystin-LR. The procedure was simple, and a recovery rate of 94% was achieved following elution in 1 ml of 100% methanol. Large-scale, low-cost production of anti-microcystin-LR scAb in E. coli is an exciting prospect for the development of biosensors and on-line monitoring systems for microcystins and will also facilitate a range of immunoaffinity applications for the cleanup and concentration of these toxins from environmental samples. PMID:12406716

Genes, Genomes, and Assemblages of Modern Anoxygenic Photosynthetic Cyanobacteria as Proxies for Ancient Cyanobacteria

Science.gov (United States)

Grim, S. L.; Dick, G.

2015-12-01

Oxygenic photosynthetic (OP) cyanobacteria were responsible for the production of O2 during the Proterozoic. However, the extent and degree of oxygenation of the atmosphere and oceans varied for over 2 Ga after OP cyanobacteria first appeared in the geologic record. Cyanobacteria capable of anoxygenic photosynthesis (AP) may have altered the trajectory of oxygenation, yet the scope of their role in the Proterozoic is not well known. Modern cyanobacterial populations from Middle Island Sinkhole (MIS), Michigan and a handful of cultured cyanobacterial strains, are capable of OP and AP. With their metabolic versatility, these microbes may approximate ancient cyanobacterial assemblages that mediated Earth's oxygenation. To better characterize the taxonomic and genetic signatures of these modern AP/OP cyanobacteria, we sequenced 16S rRNA genes and conducted 'omics analyses on cultured strains, lab mesocosms, and MIS cyanobacterial mat samples collected over multiple years from May to September. Diversity in the MIS cyanobacterial mat is low, with one member of Oscillatoriales dominating at all times. However, Planktothrix members are more abundant in the cyanobacterial community in late summer and fall. The shift in cyanobacterial community composition may be linked to seasonally changing light intensity. In lab mesocosms of MIS microbial mat, we observed a shift in dominant cyanobacterial groups as well as the emergence of Chlorobium, bacteria that specialize in AP. These shifts in microbial community composition and metabolism are likely in response to changing environmental parameters such as the availability of light and sulfide. Further research is needed to understand the impacts of the changing photosynthetic community on oxygen production and the entire microbial consortium. Our study connects genes and genomes of AP cyanobacteria to their environment, and improves understanding of cyanobacterial metabolic strategies that may have shaped Earth's redox evolution.

The failure combination method: presentation, application to a simple collection of systems

International Nuclear Information System (INIS)

Llory, M.; Villemeur, A.

1981-11-01

The main advantages of this particular method for analyzing the reliability and safety of systems, the method of failure combinations, are presented. This is an inductive method of analysis; it makes it possible to pursue the Failure Modes and Effect Analysis (FMEA) until overall failures are obtained. In this manner, through an inductive approach all the combinations of failure modes leading to abnormal functioning of systems are obtained. It also makes it possible to carry out the overall study of complex systems in interaction and the systematic inventory of abnormal functioning of these systems, as from the failure modes of the components and their combinations. It can be used as from the design stages of systems and is an excellent dialogue tool between the various specialists concerned in problems of safety, operation and reliability [fr

Spatial Variability of Cyanobacteria and Heterotrophic Bacteria in Lake Taihu (China).

Science.gov (United States)

Qian, Haifeng; Lu, Tao; Song, Hao; Lavoie, Michel; Xu, Jiahui; Fan, Xiaoji; Pan, Xiangliang

2017-09-01

Cyanobacterial blooms frequently occur in Lake Taihu (China), but the intertwined relationships between biotic and abiotic factors modulating the frequency and duration of the blooms remain enigmatic. To better understand the relationships between the key abiotic and biotic factors and cyanobacterial blooms, we measured the abundance and diversity of prokaryotic organisms by high-throughput sequencing, the abundance of key genes involved in microcystin production and nitrogen fixation or loss as well as several physicochemical parameters at several stations in Lake Taihu during a cyanobacterial bloom of Microcystis sp.. Measurements of the copy number of denitrification-related genes and 16S rRNA analyses show that denitrification potential and denitrifying bacteria abundance increased in concert with non-diazotrophic cyanobacteria (Microcystis sp.), suggesting limited competition between cyanobacteria and heterotrophic denitrifiers for nutrients, although potential bacteria-mediated N loss may hamper Microcystis growth. The present study provides insight into the importance of different abiotic and biotic factors in controlling cyanobacteria and heterotrophic bacteria spatial variability in Lake Taihu.

Emerging experimental and computational technologies for purpose designed engineering of photosynthetic prokaryotes

KAUST Repository

Lindblad, Peter

2016-01-25

With recent advances in synthetic molecular tools to be used in photosynthetic prokaryotes, like cyanobacteria, it is possible to custom design and construct microbial cells for specific metabolic functions. This cross-disciplinary area of research has emerged within the interfaces of advanced genetic engineering, computational science, and molecular biotechnology. We have initiated the development of a genetic toolbox, using a synthetic biology approach, to custom design, engineer and construct cyanobacteria for selected function and metabolism. One major bottleneck is a controlled transcription and translation of introduced genetic constructs. An additional major issue is genetic stability. I will present and discuss recent progress in our development of genetic tools for advanced cyanobacterial biotechnology. Progress on understanding the electron pathways in native and engineered cyanobacterial enzymes and heterologous expression of non-native enymzes in cyanobacterial cells will be highlighted. Finally, I will discuss our attempts to merge synthetic biology with synthetic chemistry to explore fundamantal questions of protein design and function.

Cyanobacteria and cyanotoxins in fishponds and their effects on fish tissue.

Science.gov (United States)

Drobac, Damjana; Tokodi, Nada; Lujić, Jelena; Marinović, Zoran; Subakov-Simić, Gordana; Dulić, Tamara; Važić, Tamara; Nybom, Sonja; Meriluoto, Jussi; Codd, Geoffrey A; Svirčev, Zorica

2016-05-01

Cyanobacteria can produce toxic metabolites known as cyanotoxins. Common and frequently investigated cyanotoxins include microcystins (MCs), nodularin (NOD) and saxitoxins (STXs). During the summer of 2011 extensive cyanobacterial growth was found in several fishponds in Serbia. Sampling of the water and fish (common carp, Cyprinus carpio) was performed. Water samples from 13 fishponds were found to contain saxitoxin, microcystin, and/or nodularin. LC-MS/MS showed that MC-RR was present in samples of fish muscle tissue. Histopathological analyses of fish grown in fishponds with cyanotoxin production showed histopathological damage to liver, kidney, gills, intestines and muscle tissues. This study is among the first so far to report severe hyperplasia of intestinal epithelium and severe degeneration of muscle tissue of fish after cyanobacterial exposure. These findings emphasize the importance of cyanobacterial and cyanotoxin monitoring in fishponds in order to recognize cyanotoxins and their potential effects on fish used for human consumption and, further, on human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Remote sampling system in reprocessing: present and future perspective

International Nuclear Information System (INIS)

Garcha, J.S.; Balakrishnan, V.P.; Rao, M.K.

1990-01-01

For the process and inventory control of the reprocessing plant operation it is essential to analyse the samples from the various process vessels to assess the plant performance and take corrective action if needed in the operating parameters. In view of the very high radioactive inventory in the plant, these plants are operated remotely behind thick shielding. The liquid sampling also has to be carried out by remote techniques only as no direct approach is feasible. A vacuum assisted air lift method is employed for the purpose of obtaining samples from remotely located process vessels. A brief description of the present technique, the design criteria, various interlocks and manual operations involved during sampling and despatching the same to the analytical laboratory is given in the paper. A design approach for making the sampling system, a fully automated remote operation has been attempted in this paper. Utilisation of custom built robots and dedicated computer for the various operations and interlocks has been visualised to ensure a complete remotised system for the adoption in future plants. (author). 2 figs., 2 tabs

76 FR 55213 - Technical Amendments to Federal Employees' Retirement System; Present Value Conversion Factors...

Science.gov (United States)

2011-09-07

... Employees' Retirement System; Present Value Conversion Factors for Spouses of Deceased Separated Employees... to read as follows: Appendix A to Subpart C of Part 843--Present Value Conversion Factors for Earlier...

System to determine present elements in oily samples; Sistema para determinar elementos presentes en muestras oleosas

Energy Technology Data Exchange (ETDEWEB)

Mendoza G, Y

2004-11-01

In the Chemistry Department of the National Institute of Nuclear Investigations of Mexico, dedicated to analyze samples of oleaginous material and of another origin, to determine the elements of the periodic table present in the samples, through the Neutron activation analysis technique (NAA). This technique has been developed to determine majority elements in any solid, aqueous, industrial and environmental sample, which consists basically on to irradiate a sample with neutrons coming from the TRIGA Mark III reactor and to carry out the analysis to obtain those gamma spectra that it emits, for finally to process the information, the quantification of the analysis it is carried out in a manual way, which requires to carry out a great quantity of calculations. The main objective of this project is the development of a software that allows to carry out the quantitative analysis of the NAA for the multielemental determination of samples in an automatic way. To fulfill the objective of this project it has been divided in four chapters: In the first chapter it is shortly presented the history on radioactivity and basic concepts that will allow us penetrate better to this work. In the second chapter the NAA is explained which is used in the sample analysis, the description of the process to be carried out, its are mentioned the characteristics of the used devices and an example of the process is illustrated. In the third chapter it is described the development of the algorithm and the selection of the programming language. The fourth chapter it is shown the structure of the system, the general form of operation, the execution of processes and the obtention of results. Later on the launched results are presented in the development of the present project. (Author)

Respiratory toxicity of cyanobacterial aphantoxins from Aphanizomenon flos-aquae DC-1 in the zebrafish gill

Energy Technology Data Exchange (ETDEWEB)

Zhang, De Lu, E-mail: deluzh@163.com [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Liu, Si Yi [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Jing [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Zhang, Jian Kun [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Hu, Chun Xiang, E-mail: cxhu@ihb.ac.cn [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China); Liu, Yong Ding [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China)

2016-07-15

aphantoxins or PSPs lead to structural damage and altered function in the gills of zebrafish, including changes in histological structure and increases in the activities of AST and ALT. The inhibition of the activities of AChE and MAO suggest that aphantoxins or PSPs could induce respiratory toxicity in the zebrafish gill. Furthermore, these parameters may be used as bioindicators for investigating aphantoxin exposure and cyanobacterial blooms in nature.

Toxicology of freshwater cyanobacteria.

Science.gov (United States)

Liyanage, H M; Arachchi, D N Magana; Abeysekara, T; Guneratne, L

2016-07-02

Many chemical contaminants in drinking water have been shown to cause adverse health effects in humans after prolonged exposure. Cyanobacteria are one of the most potent and diverse groups of photosynthetic prokaryotes. One key component of cyanobacterial success in the environment is the production of potent toxins as secondary metabolites, which have been responsible for numerous adverse health impacts in humans. Anthropogenic activities have led to the increase of eutrophication in freshwater bodies' worldwide, causing cyanobacterial blooms to become more frequent. The present article will discuss about harmful cyanobacteria and their toxicology with special references to microcystin, nodularin, and cylindrospermopsin.

Present status of cryogenic system for e-linac at VECC

International Nuclear Information System (INIS)

Ahammed, Manir; Mondal, Manas; Pal, Sandip; Duttagupta, Anjan; Bandyopadhyay, Arup; Naik, Vaishali; Chakrabarti, Alok; Laxdal, Robert E.; Koveshnikov, Alexy

2015-01-01

VECC is constructing a 50 MeV, 100 kW, superconducting electron linear accelerator (e-Linac) for the upcoming ANURIB (Advanced National facility for Unstable and Rare Isotope Beams) project at the new campus. Presently a 10 MeV injector for the e-Linac is being developed in collaboration with TRIUMF laboratory in Canada.The Injector comprises a 300 kV electron gun, low energy beam transport (LEBT) line and an injector cryo-module (ICM) that houses one 9-cell beta=1, 1.3 GHz niobium elliptical cavity operated at 2K. Alternatively, a capture cryo-module (CCM) having two single cell beta=1, 1.3 GHz niobium cavities that will allow the electron gun to be operated at 100 kV is also being developed. The e-Linac has been jointly designed by VECC and TRIUMF. The ICM is being built by TRIUMF whereas front-end of the injector is being built indigenously at VECC. In this report the details and present status of the cryogenic system for the e-Linac will be presented

One Health and Cyanobacteria in Freshwater Systems: Animal Illnesses and Deaths are Sentinel Events for Human Health Risks

Science.gov (United States)

Harmful cyanobacterial blooms have adversely impacted human and animal health for thousands of years. Recently, the health impacts of harmful cyanobacteria blooms are becoming more frequently detected and reported. However, reports of human and animal illnesses or deaths associat...

Past, present, and future design of urban drainage systems with focus on Danish experiences

DEFF Research Database (Denmark)

Arnbjerg-Nielsen, Karsten

2011-01-01

over time? Based on an analysis of the underlying key drivers of changes that are expected to affect urban drainage systems the current problems and their predicted development over time are presented. One key issue is management of risk and uncertainties and therefore a framework for design......Climate change will influence the water cycle substantially, and extreme precipitation will become more frequent in many regions in the years to come. How should this fact be incorporated into design of urban drainage systems, if at all? And how important is climate change compared to other changes...... and analysis of urban structures in light of present and future uncertainties is presented....

Cost-volume-profit and net present value analysis of health information systems.

Science.gov (United States)

McLean, R A

1998-08-01

The adoption of any information system should be justified by an economic analysis demonstrating that its projected benefits outweigh its projected costs. Analysis differ, however, on which methods to employ for such a justification. Accountants prefer cost-volume-profit analysis, and economists prefer net present value analysis. The article explains the strengths and weaknesses of each method and shows how they can be used together so that well-informed investments in information systems can be made.

Functional network macroscopes for probing past and present Earth system dynamics (Invited)

Science.gov (United States)

Donges, J. F.

2013-12-01

The Earth, as viewed from a physicist's perspective, is a dynamical system of great complexity. Functional complex networks are inferred from observational data and model runs or constructed on the basis of theoretical considerations. Representing statistical interdependencies or causal interactions between objects (e.g., Earth system subdomains, processes, or local field variables), functional complex networks are conceptually well-suited for naturally addressing some of the fundamental questions of Earth system analysis concerning, among others, major dynamical patterns, teleconnections, and feedback loops in the planetary machinery, as well as critical elements such as thresholds, bottlenecks, and switches. The first part of this talk concerns complex network theory and network-based time series analysis. Regarding complex network theory, the novel contributions include consistent frameworks for analyzing the topology of (i) general networks of interacting networks and (ii) networks with vertices of heterogeneously distributed weights, as well as (iii) an analytical theory for describing spatial networks. In the realm of time series analysis, (i) recurrence network analysis is put forward as a theoretically founded, nonlinear technique for the study of single, but possibly multivariate time series. (ii) Coupled climate networks are introduced as an exploratory tool of data analysis for quantitatively characterizing the intricate statistical interdependency structure within and between several fields of time series. The second part presents applications for detecting dynamical transitions (tipping points) in time series and studying bottlenecks in the atmosphere's general circulation structure. The analysis of paleoclimate data reveals a possible influence of large-scale shifts in Plio-Pleistocene African climate variability on events in human evolution. This presentation summarizes the contents of the dissertation titled "Functional network macroscopes for

Presentation of the escadre system, together with a practical application

International Nuclear Information System (INIS)

Dufresne, J.; Cenerino, G.; Dumas, J.M.; Gauvain, J.; Fermandjian, J.; L'Heriteau, J.P.; Lhiaubet, G.

1988-08-01

The Institute for Nuclear Safety and Protection (IPSN) is in charge of research in phenomenology of severe accidents which are not taken into account in the design basis but which could occur on the dfferent types of reactor operated in France. Related potential applications are varied and include: - assessment of radioactive release as to nature, quantity and kinetics, in order to validate the population evacuation plans, - analysis of the efficiency of the procedures and corrective actions envisaged by the operating utilities to minimize the consequences of severe accidents, - general risk surveys for the PRA programs. In order to carry out this task effectively, the IPSN has developed a set of computer programs to model on the one hand, the physics of fission product transfers (release from damaged fuel, vapour and aerosol behavior, transport outside the reactor containment), and on the other hand, the core, primary system and containment thermal hydraulics (including the incidence of safeguard systems, ultimate emergency procedures and corium-concrete interaction) determining fission product transfer kinetics. The system is completed by provision for modelling fission product atmophere, aquatic and hydrological transfers outside the containment. This computer program, known as ESCADRE, is presented in this paper

An Automatic Monitoring System for High-Frequency Measuring and Real-Time Management of Cyanobacterial Blooms in Urban Water Bodies

Directory of Open Access Journals (Sweden)

Viet Tran Khac

2018-01-01

Full Text Available Urban lakes mitigate the negative impacts on the hydrological cycle and improve the quality of life in cities. Worldwide, the concern increases for the protection and management of urban water bodies. Since the physical-chemical and biological conditions of a small aquatic ecosystem can vary rapidly over time, traditional low frequency measurement approaches (weekly or monthly sampling limits the knowledge and the transfer of research outcomes to management decision-making. In this context, this paper presents an automatic monitoring system including a full-scale experimental site and a data transfer platform for high-frequency observations (every 5 min in a small and shallow urban lake (Lake Champs-sur-Marne, Paris, France, 10.3 ha. Lake stratification and mixing periods can be clearly observed, these periods are compared with the dynamic patterns of chlorophyll-a, phycocyanin, dissolved oxygen and pH. The results indicate that the phytoplankton growth corresponds with dissolved oxygen cycles. However, thermal stratification cannot totally explain the entire dynamic patterns of different physical-chemical and ecological variables. Besides, the cyanobacteria is one of the dominating groups of phytoplankton blooms during the lake stratification periods (8 August–29 September 2016. During the cooling mixed period (29 September–19 October 2016, the high concentration of chlorophyll-a is mainly caused by the other phytoplankton species, such as diatoms. Perspectives are discussed in order to apply this observation system for real-time management of water bodies and lakes.

Current status of multiple antigen-presenting peptide vaccine systems: Application of organic and inorganic nanoparticles

Directory of Open Access Journals (Sweden)

Taguchi Hiroaki

2011-08-01

Full Text Available Abstract Many studies are currently investigating the development of safe and effective vaccines to prevent various infectious diseases. Multiple antigen-presenting peptide vaccine systems have been developed to avoid the adverse effects associated with conventional vaccines (i.e., live-attenuated, killed or inactivated pathogens, carrier proteins and cytotoxic adjuvants. Recently, two main approaches have been used to develop multiple antigen-presenting peptide vaccine systems: (1 the addition of functional components, e.g., T-cell epitopes, cell-penetrating peptides, and lipophilic moieties; and (2 synthetic approaches using size-defined nanomaterials, e.g., self-assembling peptides, non-peptidic dendrimers, and gold nanoparticles, as antigen-displaying platforms. This review summarizes the recent experimental studies directed to the development of multiple antigen-presenting peptide vaccine systems.

Groundwater shapes sediment biogeochemistry and microbial diversity in a submerged Great Lake sinkhole.

Science.gov (United States)

Kinsman-Costello, L E; Sheik, C S; Sheldon, N D; Allen Burton, G; Costello, D M; Marcus, D; Uyl, P A Den; Dick, G J

2017-03-01

For a large part of earth's history, cyanobacterial mats thrived in low-oxygen conditions, yet our understanding of their ecological functioning is limited. Extant cyanobacterial mats provide windows into the putative functioning of ancient ecosystems, and they continue to mediate biogeochemical transformations and nutrient transport across the sediment-water interface in modern ecosystems. The structure and function of benthic mats are shaped by biogeochemical processes in underlying sediments. A modern cyanobacterial mat system in a submerged sinkhole of Lake Huron (LH) provides a unique opportunity to explore such sediment-mat interactions. In the Middle Island Sinkhole (MIS), seeping groundwater establishes a low-oxygen, sulfidic environment in which a microbial mat dominated by Phormidium and Planktothrix that is capable of both anoxygenic and oxygenic photosynthesis, as well as chemosynthesis, thrives. We explored the coupled microbial community composition and biogeochemical functioning of organic-rich, sulfidic sediments underlying the surface mat. Microbial communities were diverse and vertically stratified to 12 cm sediment depth. In contrast to previous studies, which used low-throughput or shotgun metagenomic approaches, our high-throughput 16S rRNA gene sequencing approach revealed extensive diversity. This diversity was present within microbial groups, including putative sulfate-reducing taxa of Deltaproteobacteria, some of which exhibited differential abundance patterns in the mats and with depth in the underlying sediments. The biological and geochemical conditions in the MIS were distinctly different from those in typical LH sediments of comparable depth. We found evidence for active cycling of sulfur, methane, and nutrients leading to high concentrations of sulfide, ammonium, and phosphorus in sediments underlying cyanobacterial mats. Indicators of nutrient availability were significantly related to MIS microbial community composition, while LH

Response of cyanobacteria to the fountain-based water aeration system in Jeziorak Mały urban lake

Directory of Open Access Journals (Sweden)

Zębek Elżbieta

2014-03-01

Full Text Available This study of cyanobacteria phytoplankton was conducted from May to August in 2002, 2003 and 2005 during fountain-based water aeration in the pelagial of the Jeziorak Mały urban lake in Poland. Additional water mixing by this installation’s activity changed the cyanobacterial growth conditions. Although less of their proportion was noted in total phytoplankton abundance, higher mean abundance and biomass were recorded at the fountain than at the lake centre. Higher water temperature in the surface layer favoured cyanobacterial growth at the fountain, while higher iron concentration stimulated their development in the lake’s centre. This was supported by positive correlations between their abundance and these water parameters. Moreover, the fountain’s activity contributed to the cyanobacteria sinking in the water column. The higher abundance of cyanobacteria was found at 1m depth in May, July and August than in the fountain surface layer. Additional water mixing during fountain activity caused also a shift in their abundance maximum (C - June and F - August and contributed to intensive organic matter decomposition. These conditions promoted cyanobacterial nutrient uptake from the water at the fountain, and this is supported by the negative correlation between their abundance and orthophosphate and total nitrogen concentrations. Generally, water mixing during the fountain’s activity does not inhibit the growth of cyanobacteria. This phenomenon disturbed abundance dynamics of the cyanobacteria in summer months but didn’t contribute to their abundance decrease. It is important for these results to be considered in future management of shallow urban lakes.

Units of measurement past, present and future international system of units

CERN Document Server

Gupta, S V

2010-01-01

It is for the first time that the subject of quantities and their respective units is dealt this much in detail a glimpse of units of measurements of base quantities of length, time, mass and volume is given for ancient India three and four dimensional systems of measurement units are critically examined establishment of the fact that only four base units are needed to describe a system of units the basics to arrive at the unit of a derived quantity are explained basic, derived and dimensionless quantities including quantity calculus are introduced life history of scientists concerned with measurements units are presented to be inspiring to working metrologists and students. The International System of Units including, Metre Convention Treaty and its various organs including International National of Weights and Measure are described. The realisation of base units is given in detail. Classes of derived units within the SI, units permitted for time to come, units outside SI but used in special fields of measur...

Behavioral Risk Factor Surveillance System (BRFSS) Age-Adjusted Prevalence Data (2011 to present)

Data.gov (United States)

U.S. Department of Health & Human Services — 2011 to present. BRFSS combined land line and cell phone age-adjusted prevalence data. The BRFSS is a continuous, state-based surveillance system that collects...

Utilization of KSC Present Broadband Communications Data System for Digital Video Services

Science.gov (United States)

Andrawis, Alfred S.

2002-01-01

This report covers a visibility study of utilizing present KSC broadband communications data system (BCDS) for digital video services. Digital video services include compressed digital TV delivery and video-on-demand. Furthermore, the study examines the possibility of providing interactive video on demand to desktop personal computers via KSC computer network.

Streptococcus pneumoniae sepsis as the initial presentation of systemic lupus erythematosus

Directory of Open Access Journals (Sweden)

Erdem I

2016-09-01

Full Text Available Ilknur Erdem,1 Senay Elbasan Omar,1 Ridvan Kara Ali,1 Hayati Gunes,2 Aynur Eren Topkaya2 1Department of Infectious Diseases, 2Department of Medical Microbiology, Faculty of Medicine, Namik Kemal University, Tekirdag, Turkey Objective: Infections are among the most important causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE but are rare initial presentation of the disease. Therefore, in this study, we describe a case of Streptococcus pneumoniae sepsis in a young woman with previously undiagnosed SLE. Case report: A 23-year-old female patient was admitted to our outpatient clinic complaining of high fever (40°C, chills, fatigue, generalized myalgia, and cough with brown sputum for 5 days. Blood cultures grew gram-positive coccus defined as S. pneumoniae using standard procedures. Antinuclear antibody was positive at a titer of 1/1,000, and anti-double-stranded DNA was positive at 984 IU/mL. She was diagnosed with SLE. Her respiratory symptoms and pleural effusion were considered to be due to pulmonary manifestation of SLE. Conclusion: The underlying immunosuppression caused by SLE could have predisposed the patient to invasive pneumococcal disease. It may also occur as a primary presenting feature, although a rare condition. Keywords: Streptococcus pneumoniae, sepsis, systemic lupus erythematosus

Substrates of Peltigera Lichens as a Potential Source of Cyanobionts.

Science.gov (United States)

Zúñiga, Catalina; Leiva, Diego; Carú, Margarita; Orlando, Julieta

2017-10-01

Photobiont availability is one of the main factors determining the success of the lichenization process. Although multiple sources of photobionts have been proposed, there is no substantial evidence confirming that the substrates on which lichens grow are one of them. In this work, we obtained cyanobacterial 16S ribosomal RNA gene sequences from the substrates underlying 186 terricolous Peltigera cyanolichens from localities in Southern Chile and maritime Antarctica and compared them with the sequences of the cyanobionts of these lichens, in order to determine if cyanobacteria potentially available for lichenization were present in the substrates. A phylogenetic analysis of the sequences showed that Nostoc phylotypes dominated the cyanobacterial communities of the substrates in all sites. Among them, an overlap was observed between the phylotypes of the lichen cyanobionts and those of the cyanobacteria present in their substrates, suggesting that they could be a possible source of lichen photobionts. Also, in most cases, higher Nostoc diversity was observed in the lichens than in the substrates from each site. A better understanding of cyanobacterial diversity in lichen substrates and their relatives in the lichens would bring insights into mycobiont selection and the distribution patterns of lichens, providing a background for hypothesis testing and theory development for future studies of the lichenization process.

Present SLAC accelerator computer control system features

International Nuclear Information System (INIS)

Davidson, V.; Johnson, R.

1981-02-01

The current functional organization and state of software development of the computer control system of the Stanford Linear Accelerator is described. Included is a discussion of the distribution of functions throughout the system, the local controller features, and currently implemented features of the touch panel portion of the system. The functional use of our triplex of PDP11-34 computers sharing common memory is described. Also included is a description of the use of pseudopanel tables as data tables for closed loop control functions

Structure and data presentation in the data acquisition system for the SFINKS device

International Nuclear Information System (INIS)

Kul'man, N.Yu.

1988-01-01

The aim of the paper is to create a convenient system to describe the data structure coming from the data acquisition electronics. A language to describe the data structure to accordance with the setup detectors which allows one to make changes in the processing system with the changes of the setup configuration has been proposed. The inner presentation is realized in the form of trees in the ZBOOK system, widely used in high energy physics. Events are treated according to the description and are in the ZBOOK banks. The data are written on the tape in the computer-independent EP-format

Development of the electric power system in Macedonia - past, present, future state

International Nuclear Information System (INIS)

1996-01-01

The first part presents an overview of the chronological development of the Electric Power System (EPS) of Macedonia. The second part is dedicated to its present situation and to the actual operation conditions and problems in this regard. The third part describes the development engagements. These engagements are directed on one hand, towards finding solutions for the energy conditions in the next 5-10 years and, on the other hand, towards the preparation of the electrical plants and objects for the next 25-40 years, which are determined by various development parameters for the general and industrial progress of the state. (author)

Study of anti-inflammatory, anti-diabetic, and analgesic activity of ...

African Journals Online (AJOL)

Admin

2012-04-17

Apr 17, 2012 ... Natural products have been isolated from wide variety of taxa and tested ... Studies on marine cyanobacterial species ... compound present in the extract of O. annae. MATERIALS AND METHODS. Algae and culture conditions.

Methods for the selective detection of alkyne-presenting molecules and related compositions and systems

Science.gov (United States)

Valdez, Carlos A.; Vu, Alexander K.

2017-10-17

Provided herein are methods for selectively detecting an alkyne-presenting molecule in a sample and related detection reagents, compositions, methods and systems. The methods include contacting a detection reagent with the sample for a time and under a condition to allow binding of the detection reagent to the one or more alkyne-presenting molecules possibly present in the matrix to the detection reagent. The detection reagent includes an organic label moiety presenting an azide group. The binding of the azide group to the alkyne-presenting molecules results in emission of a signal from the organic label moiety.

Associations between cyanobacteria and indices of secondary production in the western basin of Lake Erie

Science.gov (United States)

Larson, James H.; Evans, Mary Anne; Kennedy, Robert J.; Bailey, Sean; Loftin, Keith A.; Laughrey, Zachary; Femmer, Robin; Schaeffer, Jeff; Richardson, William B.; Wynne, Timothy; Nelson, J. C.; Duris, Joseph W.

2018-01-01

Large lakes provide a variety of ecological services to surrounding cities and communities. Many of these services are supported by ecological processes that are threatened by the increasing prevalence of cyanobacterial blooms which occur as aquatic ecosystems experience cultural eutrophication. Over the past 10 yr, Lake Erie experienced cyanobacterial blooms of increasing severity and frequency, which have resulted in impaired drinking water for the surrounding communities. Cyanobacterial blooms may impact ecological processes that support other services, but many of these impacts have not been documented. Secondary production (production of primary consumers) is an important process that supports economically important higher trophic levels. Cyanobacterial blooms may influence secondary production because cyanobacteria are a poor‐quality food resource and cyanotoxins may be harmful to consumers. Over 3 yr at 34 sites across the western basin of Lake Erie, we measured three indices of secondary production that focus on the dominant bivalve taxa: (1) growth of a native unionid mussel, (2) the size of young‐of‐year dreissenid mussels, and (3) the mass of colonizing animals on a Hester‐Dendy sampler. Associations between these indices and cyanobacterial data were estimated to assess whether cyanobacteria are associated with variation in secondary production in the western basin of Lake Erie. The results suggest cyanobacterial abundance alone is only weakly associated with secondary production, but that cyanotoxins have a larger effect on secondary production. Given recurring late‐summer cyanobacterial blooms, this impact on secondary production has the potential to undermine Lake Erie's ability to sustain important ecosystem services.

Effect of salinity changes on the bacterial diversity, photosynthesis and oxygen consumption of cyanobacterial mats from an intertidal flat of the Arabian Gulf.

Science.gov (United States)

Abed, Raeid M M; Kohls, Katharina; de Beer, Dirk

2007-06-01

The effects of salinity fluctuation on bacterial diversity, rates of gross photosynthesis (GP) and oxygen consumption in the light (OCL) and in the dark (OCD) were investigated in three submerged cyanobacterial mats from a transect on an intertidal flat. The transect ran 1 km inland from the low water mark along an increasingly extreme habitat with respect to salinity. The response of GP, OCL and OCD in each sample to various salinities (65 per thousand, 100 per thousand, 150 per thousand and 200 per thousand) were compared. The obtained sequences and the number of unique operational taxonomic units showed clear differences in the mats' bacterial composition. While cyanobacteria decreased from the lower to the upper tidal mat, other bacterial groups such as Chloroflexus and Cytophaga/Flavobacteria/Bacteriodetes showed an opposite pattern with the highest dominance in the middle and upper tidal mats respectively. Gross photosynthesis and OCL at the ambient salinities of the mats decreased from the lower to the upper tidal zone. All mats, regardless of their tidal location, exhibited a decrease in areal GP, OCL and OCD rates at salinities > 100 per thousand. The extent of inhibition of these processes at higher salinities suggests an increase in salt adaptation of the mats microorganisms with distance from the low water line. We conclude that the resilience of microbial mats towards different salinity regimes on intertidal flats is accompanied by adjustment of the diversity and function of their microbial communities.

Present status of control system at the SRRC

International Nuclear Information System (INIS)

Jan, G.J.; Chen, J.; Chen, C.J.; Wang, C.S.

1992-01-01

The modern control technique was used to design and set up a control system for the synchrotron radiation facilities at the synchrotron radiation research center (SRRC). This control system will be finally to operate the dedicated machine to provide the 1.3 GeV synchrotron radiation light. The control system will control and monitor the components of storage ring, beam transport and injector system. The concept of the philosophy is to design a unique, simple structure and object-oriented graphic display control system. The SRRC control system has the major features such as two level architecture, high speed local area network with high level protocol, high speed microprocessor based VME crate, object-oriented high performance control console and graphic display. The computer hardware system was set up and tested. The software in top level computers which include database server, network server, upload program, data access program, alarm checking and display, as well as graphics user interface (GUI) program were developed and tested. The operational system and device driver on the field level controller were implemented. The overall performance of the SRRC control system were tested and evaluation. The preliminary results showed that SRRC control system is simple, flexible, expandable and upgradable open system to control and monitor devices on the small scale synchrotron radiation facility. (author)

TMX magnet system, present and future

International Nuclear Information System (INIS)

Wong, R.L.; Pedrotti, L.R.; Leavitt, G.A.; Waugh, A.F.; Chargin, A.K.; Calderon, M.O.

1979-01-01

The magnetic field design and the mechanical design of the TMX magnet system were previously reported by Chen and Hinkle. This paper is a summary of the work that has been accomplished in the two years since then

Radio frequency systems for present and future accelerators

International Nuclear Information System (INIS)

Raka, E.C.

1987-01-01

Rf systems are described for the FNAL Main Ring and Tevatron Ring, CERN SPS and LEP, and HERA proton acceleration system, CERN PS e + e/sup minus/ acceleration system, and CERN EPA monochromatic cavity. Low impedance rf systems in CERN ISR, the Brookhaven CBA, and SSC are also discussed

A common transport system for methionine, L-methionine-DL-sulfoximine (MSX), and phosphinothricin (PPT) in the diazotrophic cyanobacterium Nostoc muscorum.

Science.gov (United States)

Singh, Arvind Kumar; Syiem, Mayashree B; Singh, Rajkumar S; Adhikari, Samrat; Rai, Amar Nath

2008-05-01

We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.

Simplified life-cycle analysis of PV systems in buildings: present situation and future trends

International Nuclear Information System (INIS)

Frankl, P.; Masini, A.; Gamberale, M.; Toccaceli, D.

1998-01-01

The integration of photovoltaic (PV) systems in buildings shows several advantages compared to conventional PV power plants. The main objectives of the present study are the quantitative evaluation of the benefits of building-integrated PV systems over their entire life-cycle and the identification of best solutions to maximise their energy efficiency and CO 2 mitigation potential. In order to achieve these objectives, a simplified life-cycle analysis (LCA) has been carried out. Firstly, a number of existing applications have been studied. Secondly, a parametric analysis of possible improvements in the balance-of-system (BOS) has been developed. Finally, the two steps have been combined with the analysis of crystalline silicon technologies. Results are reported in terms of several indicators: energy pay-back time, CO 2 yield and specific CO 2 emissions. The Indicators show that the integration of PV systems in buildings clearly increases the environmental benefits of present PV technology. These benefits will further increase with future PV technologies. Future optimised PV roof-integrated systems are expected to have an energy pay-back time of around 1-5 years (1 year with heat recovery) and to save during their lifetime more than 20 times the amount of CO 2 emitted during their manufacturing (34 times with heat recovery). (Author)

Application of carbon nanotube technology for removal of contaminants in drinking water: A review

International Nuclear Information System (INIS)

Upadhyayula, Venkata K.K.; Deng, Shuguang; Mitchell, Martha C.; Smith, Geoffrey B.

2009-01-01

Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

The Mirror Fusion Test Facility cryogenic system: Performance, management approach, and present equipment status

International Nuclear Information System (INIS)

Slack, D.S.; Chronis, W.C.

1987-01-01

The cryogenic system for the Mirror Fusion Test Facility (MFTF) is a 14-kW, 4.35-K helium refrigeration system that proved to be highly successful and cost-effective. All operating objectives were met, while remaining within a few percent of initial cost and schedule plans. The management approach used in MFTF allowed decisions to be made quickly and effectively, and it helped keep costs down. Manpower levels, extent and type of industrial participation, key aspects of subcontractor specifications, and subcontractor interactions are reviewed, as well as highlights of the system tests, operation, and present equipment status. Organizations planning large, high-technology systems may benefit from this experience with the MFTF cryogenic system

Maps of sharpness: a methodology to present results of quality control for mammographic system

International Nuclear Information System (INIS)

Oliveira, Henrique Jesus Quintino de; Marques, Marcio Alexandre; Frere, Annie France; Schiable, Homero; Marques, Paulo M. Azevedo; Irita, Ricardo Toshiyuki

1996-01-01

A new method for evaluating radiologic imaging systems quality is presented. This method intends to relate the numeric results from quality control procedures to the magnitude of shadow and penumbra in the image from given objects. This evaluation is based on a computer simulation and it can be performed for any system and any object placed in any location of the radiation field

ORF Alignment: NC_005945 [GENIUS II[Archive

Lifescience Database Archive (English)

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ORF Alignment: NC_007530 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_007530 gi|47526471 >1dlwA 1 115 7 124 8e-22 ... ref|YP_017820.1| protozoan/cyanoba...cterial globin family protein [Bacillus anthracis ... str. 'Ames Ancestor'] ref|NP_843684.1| ... protozoa...n/cyanobacterial globin family protein [Bacillus ... anthracis str. Ames] ref|YP_027388.1| ... protozoa...racis str. ... A2012] gb|AAP25170.1| protozoan/cyanobacterial globin ... family protein [Bacil...lus anthracis str. Ames] ... gb|AAT30295.1| protozoan/cyanobacterial globi

ORF Alignment: NC_003997 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_003997 gi|30261307 >1dlwA 1 115 7 124 8e-22 ... ref|YP_017820.1| protozoan/cyanoba...cterial globin family protein [Bacillus anthracis ... str. 'Ames Ancestor'] ref|NP_843684.1| ... protozoa...n/cyanobacterial globin family protein [Bacillus ... anthracis str. Ames] ref|YP_027388.1| ... protozoa...racis str. ... A2012] gb|AAP25170.1| protozoan/cyanobacterial globin ... family protein [Bacil...lus anthracis str. Ames] ... gb|AAT30295.1| protozoan/cyanobacterial globi

ORF Alignment: NC_003995 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_003995 gi|21399119 >1dlwA 1 115 7 124 8e-22 ... ref|YP_017820.1| protozoan/cyanoba...cterial globin family protein [Bacillus anthracis ... str. 'Ames Ancestor'] ref|NP_843684.1| ... protozoa...n/cyanobacterial globin family protein [Bacillus ... anthracis str. Ames] ref|YP_027388.1| ... protozoa...racis str. ... A2012] gb|AAP25170.1| protozoan/cyanobacterial globin ... family protein [Bacil...lus anthracis str. Ames] ... gb|AAT30295.1| protozoan/cyanobacterial globi

Alarm filtering and presentation

International Nuclear Information System (INIS)

Bray, M.A.

1989-01-01

This paper discusses alarm filtering and presentation in the control room of nuclear and other process control plants. Alarm generation and presentation is widely recognized as a general process control problem. Alarm systems often fail to provide meaningful alarms to operators. Alarm generation and presentation is an area in which computer aiding is feasible and provides clear benefits. Therefore, researchers have developed several computerized alarm filtering and presentation approaches. This paper discusses problems associated with alarm generation and presentation. Approaches to improving the alarm situation and installation issues of alarm system improvements are discussed. The impact of artificial intelligence (AI) technology on alarm system improvements is assessed. (orig.)

Role of habitat and great oxidation event on the occurrence of three ...

Indian Academy of Sciences (India)

We conducted a survey to find out the genes coding for cyanobacterial Ci transporters in 40 cyanobacterialphyla with respect to transporters present in Gloeobacter violaceous PCC 7421, an early-diverging cyanobacterium. Anattempt was also made to correlate the prevalence of the kind of transporter present in the ...

Interspecific differences between D. pulex and D. magna in tolerance to cyanobacteria with protease inhibitors.

Directory of Open Access Journals (Sweden)

Christian J Kuster

Full Text Available It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from different habitats in Europe and North America. To test for interspecific differences in the daphnids' tolerance to cyanobacteria, their somatic and population growth rates were determined for each D. magna and D. pulex clone after exposure to varying concentrations of two Microcystis aeruginosa strains. The M. aeruginosa strains NIVA and PCC(- contained either chymotrypsin or trypsin inhibitors, but no microcystins. Mean somatic and population growth rates on a diet with 20% NIVA were significantly more reduced in D. pulex than in D. magna. On a diet with 10% PCC(-, the population growth of D. pulex was significantly more reduced than that of D. magna. This indicates that D. magna is more tolerant to cyanobacteria with protease inhibitors than D. pulex. The reduction of growth rates was possibly caused by an interference of cyanobacterial inhibitors with proteases in the gut of Daphnia, as many other conceivable factors, which might have been able to explain the reduced growth, could be excluded as causal factors. Protease assays revealed that the sensitivities of chymotrypsins and trypsins to cyanobacterial protease inhibitors did not differ between D. magna and D. pulex. However, D. magna exhibited a 2.3-fold higher specific chymotrypsin activity than D. pulex, which explains the observed higher tolerance to cyanobacterial protease inhibitors of D. magna. The present study suggests that D. magna may control the development of cyanobacterial blooms more efficiently than D. pulex due to differences in their tolerance to cyanobacteria with protease

The anhydrobiotic cyanobacterial cell

International Nuclear Information System (INIS)

Potts, M.

1996-01-01

The cyanobacterium Nostoc commune has been developed as the prokaryotic model for the anhydrobiotic cell and it provides the means to answer fundamental questions about desiccation tolerance. The anhydrobiotic cell is characterized by its singular lack of water — with contents as low as 0.02 g H 2 O g -1 dry weight. These levels are orders of magnitude lower than those found either in bacterial spores or in cells subjected to acute salt (osmotic) stress. Mechanisms that contribute to the desiccation tolerance of N. commune include the selective stabilization of anhydrous proteins, the secretion of water- and lipid-soluble UV-absorbing pigments, and the secretion of a complex glycan that immobilizes the cells, immobilizes water stress proteins and the UV-absorbing pigments, and which may confer the properties of a mechanical glass upon colonies. Rehydration of desiccated cells induces an instantaneous resumption of metabolic activities, including membrane transport and global lipid biosynthesis. These initial recoveries may not follow classical Arrhenius-based kinetics. The rehydrating cell exhibits a stringent, stepwise recovery of physiological capacities beginning with respiration, then photosynthesis and finally nitrogen fixation. Protein turnover, de novo protein synthesis and a rapid rise in the intracellular ATP pool accompany these recoveries. During the early stages of rehydration, the de novo transcription of one gene set (rpoC1C2) is achieved using an extant DNA-dependent RNA polymerase holoenzyme that remains stable in desiccated cells. These properties of desiccation-tolerant cyanobacleria, present in extant forms such as N. commune and Chroococcidiopsis spp., may have been utilized by the eoanhydrobiotes. However, it is the desiccation-tolerant cyanobacterium as a whole, and not some collection of disparate properties, that must be considered as the primary strategy for the achievement of desiccation tolerance. (author)

Genetic divergence among toxic and non-toxic cyanobacteria of the dry zone of Sri Lanka.

Science.gov (United States)

Liyanage, Harshini M; Magana Arachchi, Dhammika N; Chandrasekaran, Naduviladath V

2016-01-01

Sri Lanka has rich cyanobacterial diversity, however, only few studies have been conducted to identify the potential toxin producers in water bodies used for human consumption. As the detection of cyanotoxin is vital in water quality management, a study was done by employing 16S rRNA gene to explore the genetic divergence, phylogenetic relationships and potential toxin producing cyanobacteria in reservoirs and well waters in the dry zone of Sri Lanka. Forty five, 16S rRNA gene sequences were assayed and phylogenetic tree was constructed. Among 45 isolates, 20 isolates were classified as unidentified cyanobacteria and considered as novel cyanobacterial genera. Of 25 identified isolates, seven isolates were identified up to species level. With 16S rRNA phylogeny, 20 unidentified cyanobacterial isolates were able to place on their taxonomic positions up to order level. Results revealed that water samples understudy had vast cyanobacterial diversity with potential microcystin (MC) and cylindrospermopsin (CYN) producers and eleven clusters clearly demonstrated five cyanobacterial orders with more than 90% similarity irrespective to their toxicity which showed the suitability of 16S rRNA gene for taxonomic differentiation. Sixteen isolates had the potential to produce MC and two isolates to produce CYN. Findings of the study confirm the rich cyanobacterial diversity and the divergence among the potential cyanotoxin producers in the dry zone water bodies of Sri Lanka.

Cyanotoxins are not implicated in the etiology of coral black band disease outbreaks on Pelorus Island, Great Barrier Reef.

Science.gov (United States)

Glas, Martin S; Motti, Cherie A; Negri, Andrew P; Sato, Yui; Froscio, Suzanne; Humpage, Andrew R; Krock, Bernd; Cembella, Allan; Bourne, David G

2010-07-01

Cyanobacterial toxins (i.e. microcystins) produced within the microbial mat of coral black band disease (BBD) have been implicated in disease pathogenicity. This study investigated the presence of toxins within BBD lesions and other cyanobacterial patch (CP) lesions, which, in some instances ( approximately 19%), facilitated the onset of BBD, from an outbreak site at Pelorus Island on the inshore, central Great Barrier Reef (GBR). Cyanobacterial species that dominated the biomass of CP and BBD lesions were cultivated and identified, based on morphology and 16S rRNA gene sequences, as Blennothrix- and Oscillatoria-affiliated species, respectively, and identical to cyanobacterial sequences retrieved from previous molecular studies from this site. The presence of the cyanotoxins microcystin, cylindrospermopsin, saxitoxin, nodularin and anatoxin and their respective gene operons in field samples of CP and BBD lesions and their respective culture isolations was tested using genetic (PCR-based screenings), chemical (HPLC-UV, FTICR-MS and LC/MS(n)) and biochemical (PP2A) methods. Cyanotoxins and cyanotoxin synthetase genes were not detected in any of the samples. Cyanobacterial species dominant within CP and BBD lesions were phylogenetically distinct from species previously shown to produce cyanotoxins and isolated from BBD lesions. The results from this study demonstrate that cyanobacterial toxins appear to play no role in the pathogenicity of CP and BBD at this site on the GBR.

Impact of Environmental Factors on the Regulation of Cyanotoxin Production

Science.gov (United States)

Boopathi, Thangavelu; Ki, Jang-Seu

2014-01-01

Cyanobacteria are capable of thriving in almost all environments. Recent changes in climatic conditions due to increased human activities favor the occurrence and severity of harmful cyanobacterial bloom all over the world. Knowledge of the regulation of cyanotoxins by the various environmental factors is essential for effective management of toxic cyanobacterial bloom. In recent years, progress in the field of molecular mechanisms involved in cyanotoxin production has paved the way for assessing the role of various factors on the cyanotoxin production. In this review, we present an overview of the influence of various environmental factors on the production of major group of cyanotoxins, including microcystins, nodularin, cylindrospermopsin, anatoxins and saxitoxins. PMID:24967641

Technical Meeting on Grading of the Application of Management System Requirements. Presentations

International Nuclear Information System (INIS)

2012-01-01

The objectives of this Technical Meeting are threefold: - to share international experiences and lessons learned, as well as exchange views on best practices and strategies to overcome the difficulties encountered; - to review and discuss the draft technical report on 'Grading the Application of Management System Requirements, to allow the participants to contribute to the improvement of the document and to enrich it with practical examples; and - to strengthen the international networking of specialists in the field. The topics covered during the meeting will include: - Examples and case studies presented by participants from countries with nuclear facilities (mainly focused on NPPs, and, where appropriate, from research reactors, fuel cycle and waste management facilities) on grading the application of management system requirements and lessons learned. - Reviewing and improving the final draft of a technical report on 'Grading the Application of Management System Requirements', which will supersede the previous guidance: Grading of Quality Assurance Requirement: A Manual (Technical Reports Series No. 328)

Apparent bioaccumulation of cylindrospermopsin and paralytic shellfish toxins by finfish in Lake Catemaco (Veracruz, Mexico).

Science.gov (United States)

Berry, J P; Jaja-Chimedza, A; Dávalos-Lind, L; Lind, O

2012-01-01

Compared to the well-characterized health threats associated with contamination of fish and shellfish by algal toxins in marine fisheries, the toxicological relevance of the bioaccumulation of toxins from cyanobacteria (blue-green algae), as the primary toxigenic algae in freshwater systems, remains relatively unknown. Lake Catemaco (Veracruz, Mexico) is a small, tropical lake system specifically characterized by a year-round dominance of the known toxigenic cyanobacterial genus, Cylindrospermopsis, and by low, but detectable, levels of both a cyanobacterial hepatotoxin, cylindrospermopsin (CYN), and paralytic shellfish toxins (PSTs). In the present study, we evaluated, using enzyme-linked immunoassay (ELISA), levels of both toxins in several species of finfish caught and consumed locally in the region to investigate the bioaccumulation of, and possible health threats associated with, these toxins as potential foodborne contaminants. ELISA detected levels of both CYN and PSTs in fish tissues from the lake. Levels were generally low (≤ 1 ng g(-1) tissue); however, calculated bioaccumulation factors (BAFs) indicate that toxin levels exceed the rather low levels in the water column and, consequently, indicated bioaccumulation (BAF >1). A reasonable correlation was observed between measured bioaccumulation of CYN and PSTs, possibly indicating a mutual source of both toxins, and most likely cells of Cylindrospermopsis, the dominant cyanobacteria in the lake, and a known producer of both metabolites. The potential roles of trophic transport in the system, as well as possible implications for human health with regards to bioaccumulation, are discussed.

Numerous Fusiform and Saccular Cerebral Aneurysms in Central Nervous System Lupus Presenting with Ischemic Stroke.

Science.gov (United States)

Majidi, Shahram; Leon Guerrero, Christopher R; Gandhy, Shreya; Burger, Kathleen M; Sigounas, Dimitri

2017-07-01

Central nervous system (CNS) involvement occurs in up to 50% of patients with systemic lupus erythematosus (SLE). Cerebral aneurysm formation is a rare complication of CNS lupus. The majority of these patients present with subarachnoid hemorrhage. We report a patient with an active SLE flare who presented with a recurrent ischemic stroke and was found to have numerous unruptured fusiform and saccular aneurysms in multiple vascular territories. He was treated with high-dose steroid and rituximab along with aspirin and blood pressure control for stroke prevention. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Moving beyond the presentation layer content and context in the Dewey Decimal Classification (DDC) system

CERN Document Server

Mitchell, Joan S

2013-01-01

Can the Dewey Decimal System meet the needs of the rapidly changing information environment?Moving Beyond the Presentation Layer explores the Dewey Decimal System from a variety of perspectives, each of which peels away a bit of the ?presentation layer??the familiar linear notational sequence-to reveal the content and context offered by the DDS. Library professionals from around the word examine how the content and context offered by the DDS can evolve to meet the needs of the changing information environment, with a special focus on the impact of the Internet on current and future

Hypermedia presentation generation for semantic web information systems

NARCIS (Netherlands)

Frasincar, F.

2005-01-01

Due to Web popularity many information systems have been made available through the Web, resulting in so-called Web Information Systems (WIS). Due to the complex requirements that WIS need to ful??ll, the design of these systems is not a trivial task. Design methodologies provide guidelines for the

Hydrothermal systems on Mars: an assessment of present evidence

Science.gov (United States)

Farmer, J. D.

1996-01-01

Hydrothermal processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and hydrothermal processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient hydrothermal systems on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for hydrothermal mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient hydrothermal systems would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of hydrothermal systems being dominated by magma-cryosphere interactions. Given the smaller

Comparative Measurement of Microcystins in Diverse Surface Waters using ADDA-ELISA, LC-MS/MS, and MMPB Technical

Science.gov (United States)

The measurement of microcystins, cyanotoxins associated with cyanobacterial blooms which are increasingly prevalent in inland waters, is complicated by the diversity of congeners which have been observed in the environment. At present, more than 150 microcystin congeners have bee...

Comparative measurement of microcystins in diverse surface waters using ADDA-ELISA, LC-MS/MS, and MMPB techniques

Science.gov (United States)

The measurement of microcystins, cyanotoxins associated with cyanobacterial blooms which are increasingly prevalent in inland waters, is complicated by the diversity of congeners which have been observed in the environment. At present, more than 150 microcystin congeners have bee...

Ultra-fast secure communication with complex systems in classical channels (Conference Presentation)

KAUST Repository

Mazzone, Valerio

2017-04-28

Developing secure communications is a research area of growing interest. During the past years, several cryptographic schemes have been developed, with Quantum cryptography being a promising scheme due to the use of quantum effects, which make very difficult for an eavesdropper to intercept the communication. However, practical quantum key distribution methods have encountered several limitations; current experimental realizations, in fact, fail to scale up on long distances, as well as in providing unconditional security and speed comparable to classical optical communications channels. Here we propose a new, low cost and ultra-fast cryptographic system based on a fully classical optical channel. Our cryptographic scheme exploits the complex synchronization of two different random systems (one on the side of the sender and another on the side of the receiver) to realize a “physical” one paid system. The random medium is created by an optical chip fabricated through electron beam lithography on a Silicon On Insulator (SOI) substrate. We present experiments with ps lasers and commercial fibers, showing the ultrafast distribution of a random key between two users (Alice and Bob), with absolute no possibility for a passive/active eavesdropper to intercept the communication. Remarkably, this system enables the same security of quantum cryptography, but with the use of a classical communication channel. Our system exploits a unique synchronization that exists between two different random systems, and at such is extremely versatile and can enable safe communications among different users in standards telecommunications channels.

Toxic cyanobacteria blooms in the Lithuanian part of the Curonian Lagoon

Directory of Open Access Journals (Sweden)

Artūras Razinkovas

2009-06-01

Full Text Available The phenomenon of cyanobacteria (blue-green algae blooms in the Baltic and the surrounding freshwater bodies has been known for several decades. The presence of cyanobacterial toxic metabolites in the Curonian Lagoon has been investigated and demonstrated for the first time in this work (2006-2007. Microcystis aeruginosa was the most common and widely distributed species in the 2006 blooms. Nodularia spumigena was present in the northern part of the Curonian Lagoon, following the intrusion of brackish water from the Baltic Sea; this is the first time that this nodularin-(NOD-producing cyanobacterium has been recorded in the lagoon. With the aid of high-performance liquid chromatography (HPLC, four microcystins (MC-LR, MC-RR, MC-LY, MC-YR and nodularin were detected in 2006. The presence of these cyanobacterial hepatotoxic cyclic peptides was additionally confirmed by enzyme-linked immunosorbent assay (ELISA and protein phosphatase inhibition assay (PP1. Microcystin-LR, the most frequent of them, was present in every sample at quite high concentrations (from <0.1 to 134.2 µg dm-3. In 2007, no cyanobacterial bloom was recorded and cyanotoxins were detected in only 4% of the investigated samples. A comparably high concentration of nodularin was detected in the northern part of the Curonian Lagoon. In one sample dimethylated MC-RR was also detected (concentration 7.5 µg dm-3.

Pneumatosis Intestinalis as the Initial Presentation of Systemic Sclerosis: A Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Farshid Ejtehadi

2012-01-01

Full Text Available Introduction. Pneumatosis intestinalis (PI is an uncommon pathology characterised by the presence of gas within the intestinal wall. It has been associated with various conditions, including connective tissue diseases. This is the first report of PI being the initial presentation of systemic sclerosis. Case Presentation. The patient, a 75-year-old female, presented with an 8-month history of worsening dysphagia and epigastric pain, as well as other nonspecific symptoms. Initial investigations with an oesophagogastroduodenoscopy diagnosed Candida oesophagitis and also identified an extrinsic compression of the gastric antrum. Subsequently a CT scan of the abdomen and pelvis showed moderately dilated small bowel loops and PI. Due to the patient’s stability, non-critical clinical condition, conservative management was instituted. More detailed investigations confirmed the diagnosis of systemic sclerosis with positive anticentromeric and antinuclear antibodies. The patient improved on methotrexate and was discharged with appropriate outpatient follow-up. Discussion. PI is a rare but well-documented pathology associated with connective tissue diseases, such as systemic sclerosis. In most cases, conservative management is preferable to surgical intervention, depending on the patient’s clinical presentation and progress. This is the first report of PI being the initial presentation of a patient with systemic sclerosis responsive to conservative management.

Remote sensing of cyanobacteria-dominant algal blooms and water quality parameters in Zeekoevlei, a small hypertrophic lake, using MERIS

CSIR Research Space (South Africa)

Matthews, MW

2010-09-01

Full Text Available Eutrophication and cyanobacterial algal blooms present an increasing threat to the health of freshwater ecosystems and to humans who use these resources for drinking and recreation. Remote sensing is being used increasingly as a tool for monitoring...

Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

DEFF Research Database (Denmark)

Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo

2011-01-01

In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique...

Orofacial granulomatosis in children can be the initial manifestation of systemic disease: a presentation of two cases

DEFF Research Database (Denmark)

Simonsen, Anne Birgitte; Deleuran, Mette

2014-01-01

Orofacial granulomatosis is a chronic granulomatous condition characterized by relapsing and remitting lip swelling and oral involvement that may include deep ulcers, tags and cobblestone formation. It occurs as an independent entity but also in conjunction with systemic diseases...... such as tuberculosis, sarcoidosis and Crohn's disease. The clinical presentation is not indicative of concomitant systemic disease. To highlight the importance of thorough examination to rule out systemic disease, we present two childhood cases of orofacial granulomatosis, one of which was associated to Crohn......'s disease....

The present PC-based systems at Vietnam Atomic Energy Commission and the Y2K issue

International Nuclear Information System (INIS)

Vuong Huu Tan

1999-01-01

After finishing the IAEA TC Project oil renovation of the Dalat reactor control and instrumentation system, several PC-based systems such as Reactor Data Display System, Area Monitoring System, Reactor Protocol System and so on were newly designed and developed. These systems play an important role for observation, operation and maintenance support of the reactor. Besides, there are also several PC-based systems related to alpha, beta and gamma spectrometers. In this report we present the main functions of each system and discussion oil the Y2K issue in Vietnam and in Vietnam Atomic Energy Commission in particular. (author)

Characterizing volumetric discontinuities present in NPP heat exchangers with EASY: an eddy current data analysis system

Energy Technology Data Exchange (ETDEWEB)

Alencar, Donizete A.; Silva Junior, Silverio F., E-mail: daa@cdtn.b, E-mail: silvasf@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

Eddy current is a very important NDT inspection method widely used to perform integrity evaluation of tubes installed in heat exchangers. For nuclear power plants, a classical example is the remote inspection of steam generators and condensers, as well as other ordinary auxiliary equipment. Data evaluation can be performed by means of precise phase and amplitude measurements of complex impedance signals, represented as Lissajous figures plotted on the screen of the inspection systems. This paper presents the software EASY, a computer assisted analysis system developed at CDTN to help the characterization of volumetric discontinuities present in heat exchangers tubes. Data to be analyzed are obtained from commercial eddy current equipment data file, such as ECT MAD8D. Main advantage of that system is its portability and easy use, since it can be executed in ordinary PC, under Microsoft Windows operating system. (author)

Characterizing volumetric discontinuities present in NPP heat exchangers with EASY: an eddy current data analysis system

International Nuclear Information System (INIS)

Alencar, Donizete A.; Silva Junior, Silverio F.

2011-01-01

Eddy current is a very important NDT inspection method widely used to perform integrity evaluation of tubes installed in heat exchangers. For nuclear power plants, a classical example is the remote inspection of steam generators and condensers, as well as other ordinary auxiliary equipment. Data evaluation can be performed by means of precise phase and amplitude measurements of complex impedance signals, represented as Lissajous figures plotted on the screen of the inspection systems. This paper presents the software EASY, a computer assisted analysis system developed at CDTN to help the characterization of volumetric discontinuities present in heat exchangers tubes. Data to be analyzed are obtained from commercial eddy current equipment data file, such as ECT MAD8D. Main advantage of that system is its portability and easy use, since it can be executed in ordinary PC, under Microsoft Windows operating system. (author)

Presentation Technique

International Nuclear Information System (INIS)

Froejmark, M.

1992-10-01

The report presents a wide, easily understandable description of presentation technique and man-machine communication. General fundamentals for the man-machine interface are illustrated, and the factors that affect the interface are described. A model is presented for describing the operators work situation, based on three different levels in the operators behaviour. The operator reacts routinely in the face of simple, known problems, and reacts in accordance with predetermined plans in the face of more complex, recognizable problems. Deep fundamental knowledge is necessary for truly complex questions. Today's technical status and future development have been studied. In the future, the operator interface will be based on standard software. Functions such as zooming, integration of video pictures, and sound reproduction will become common. Video walls may be expected to come into use in situations in which several persons simultaneously need access to the same information. A summary of the fundamental rules for the design of good picture ergonomics and design requirements for control rooms are included in the report. In conclusion, the report describes a presentation technique within the Distribution Automation and Demand Side Management area and analyses the know-how requirements within Vattenfall. If different systems are integrated, such as geographical information systems and operation monitoring systems, strict demands are made on the expertise of the users for achieving a user-friendly technique which is matched to the needs of the human being. (3 figs.)

The impact of warming and nutrients on algae production and microcystins in seston from the iconic lake lesser Prespa, Greece

NARCIS (Netherlands)

Maliaka, Valentini; Faassen, Elisabeth J.; Smolders, Alfons J.P.; Lürling, Miquel

2018-01-01

Lake Lesser Prespa and its adjacent pond, Vromolimni in Greece, is a shallow freshwater system and a highly protected area hosting an exceptional biodiversity. The occurrence of microcystins (MCs) producing cyanobacterial blooms in these waters during recent years can be harmful to the wildlife. We