WorldWideScience

Sample records for nitrogen-fixing blue-green algae

  1. Effect of Nanohexaconazole on Nitrogen Fixing Blue Green Algae and Bacteria.

    Science.gov (United States)

    Kumar, Rajesh; Gopal, Madhuban; Pabbi, Sunil; Paul, Sangeeta; Alam, Md Imteyaz; Yadav, Saurabh; Nair, Kishore Kumar; Chauhan, Neetu; Srivastava, Chitra; Gogoi, Robin; Singh, Pradeep Kumar; Goswami, Arunava

    2016-01-01

    Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.

  2. Blue-green algae

    Science.gov (United States)

    ... about the use of blue-green algae during pregnancy and breast-feeding. Stay on the safe side and avoid use. "Auto-immune diseases" such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), pemphigus vulgaris (a skin ...

  3. Freshwater Cyanobacteria (Blue-Green Algae) Toxins: Isolation and Characterization

    Science.gov (United States)

    1989-01-15

    exclusively caused by strains of species that are members of the L division Cyanophyta , commonly called blue -green algae or cyanobacteria . Although...0 0 Lfl (NAD FRESHWATER CYANOBACTERIA ( BLUE -GREEN ALGAE ) TOXINS: ISOLATION AND CHARACTERIZATION ANNCUAL REPORT Wayne W. Carmichael Sarojini Bose...Frederick, Maryland 21701-5012 62770A 6277GA871 AA 378 11 TITLE &who* Secwn~y C11mrfaon) Freshwater Cyanobacteria ( blue -green algae ) Toxins: Isolation

  4. Factors influencing dark nitrogen fixation in a blue-green alga.

    Science.gov (United States)

    Fay, P

    1976-03-01

    Nitrogen-fixing activity declines first rapidly and then more gradually when Anabaenopsis circularis is transferred from light into dark conditions. The rate and duration of dark acetylene reduction (nitrogen fixation) depend upon conditions prevailing during the preceding light period. Factors (such as light intensity, CO2 concentration, and supply of glucose), which in the light affect photosynthesis and the accumulation of reserve carbon, have a profound effect on dark nitrogen fixation. Glucose greatly promotes nitrogen fixation in the light and supports prolonged nitrogenase activity in the dark. The results suggest that heterotrophic nitrogen fixation by blue-green algae in the field may be important both under light and dark conditions.

  5. [Phycobiliproteins of blue-green, red and cryptophytic algae].

    Science.gov (United States)

    Stadnichuk, I N; Gusev, M V

    1979-04-01

    The present-day concepts on phycobiliproteins, the protein pigments of blue-green, red and cryptophyte algae are reviewed. The functions, distribution, localization, physico-chemical, spectral and immunochemical properties of phycobiliproteins are described. The properties of the polypeptide protein subunits and the composition and chemical structure of chromophores as well as their binding to the apoprotein molecules are discussed.

  6. Subunit structure of the phycobiliproteins of blue-green algae.

    Science.gov (United States)

    Glazer, A N; Cohen-Bazire, G

    1971-07-01

    The phycobiliproteins of the blue-green algae Synechococcus sp. and Aphanocapsu sp. were characterized with respect to homogeneity, isoelectric point, and subunit composition. Each of the biliproteins consisted of two different noncovalently associated subunits, with molecular weights of about 20,000 and 16,000 for phycocyanin, 17,500 and 15,500 for allophycocyanin, and 22,000 and 20,000 for phycoerythrin. Covalently bound chromophore was associated with each subunit.

  7. Freshwater Cyanobacteria (Blue-Green Algae) Toxins: Isolation and Characterization

    Science.gov (United States)

    1985-10-01

    9, 1985. Toxic peptides of freshwater cyanobacteria (blue-green algae) from two European Hicr tis aegi and one Canadian &nAnbaflo s- agua were...8217Algal toxin from Potable Water Supplies: A Pilot Plant Investi- gation. p. 26 In Technical papers presented at the Tenth Federal Convention of the...W.H. Watson. Studies on aphantoxin from A12han izomenon flos- aguae in New Hampshire. In: Carmichael, W.W. (ed.) The Water Envir’onment: Algal Toxins and

  8. Phycobilisomes from Blue-Green and Red Algae

    Science.gov (United States)

    Gantt, Elisabeth; Lipschultz, Claudia A.; Grabowski, Joseph; Zimmerman, Burke K.

    1979-01-01

    A general procedure for the isolation of functionally intact phycobilisomes was devised, based on modifications of previously used procedures. It has been successful with numerous species of red and blue-green algae (Anabaena variabilis, Anacystis nidulans, Agmenellum quadruplicatum, Fremyella diplosiphon, Glaucosphaera vacuolata, Griffithsia pacifica, Nemalion multifidum, Nostoc sp., Phormidium persicinum, Porphyridium cruentum, P. sordidum, P. aerugineum, Rhodosorus marinus). Isolation was carried out in 0.75 molar K-phosphate (pH 6.8 to 7.0) at 20 to 23 C on sucrose step gradients. Lower temperature (4 to 10 C) was usually unfavorable resulting in uncoupling of energy transfer and partial dissociation of the phycobilisomes, sometimes with complete loss of allophycocyanin. Intact phycobilisomes were characterized by fluorescence emission peaks of 670 to 675 nanometers at room temperature, and 678 to 685 nanometers at liquid nitrogen temperature. Uncoupling and subsequent dissociation of phycobilisomes, in lowered ionic conditions, varied with the species and the degree of dissociation but occurred preferentially between phycocyanin and allophycocyanin, or between phycocyanin and phycoerythrin. PMID:16660778

  9. Isolation of plasmid from the blue-green alga Spirulina platensis

    Science.gov (United States)

    Qin, Song; Tong, Shun; Zhang, Peijun; Tseng, C. K.

    1993-09-01

    CCC plasmid was isolated from an economically important blue-green alga — Spirulina platensis (1.7×106 dalton from the S6 strain and 1.2×106 dalton from the F3 strain) using a rapid method based on ultrasonic disruption of algal cells and alkaline removal of chromosomal DNA. The difference in the molecular weight of the CCC DNAs from the two strains differing in form suggests that plasmid may be related with the differentiation of algal form. This modified method, which does not use any lysozyme, is a quick and effective method of plasmid isolation, especially for filamentous blue-green algae.

  10. Bioelectricity generation and microcystins removal in a blue-green algae powered microbial fuel cell.

    Science.gov (United States)

    Yuan, Yong; Chen, Qing; Zhou, Shungui; Zhuang, Li; Hu, Pei

    2011-03-15

    Bioelectricity production from blue-green algae was examined in a single chamber tubular microbial fuel cell (MFC). The blue-green algae powered MFC produced a maximum power density of 11 4 mW/m(2) at a current density of 0.55 mA/m(2). Coupled with the bioenergy generation, high removal efficiencies of chemical oxygen demand (COD) and nitrogen were also achieved in MFCs. Over 78.9% of total chemical oxygen demand (TCOD), 80.0% of soluble chemical oxygen demand (SCOD), 91.0% of total nitrogen (total-N) and 96.8% ammonium-nitrogen (NH(3)-N) were removed under closed circuit conditions in 12 days, which were much more effective than those under open circuit and anaerobic reactor conditions. Most importantly, the MFC showed great ability to remove microcystins released from blue-green algae. Over 90.7% of MC-RR and 91.1% of MC-LR were removed under closed circuit conditions (500Ω). This study showed that the MFC could provide a potential means for electricity production from blue-green algae coupling algae toxins removal.

  11. The rapid quantitation of the filamentous blue-green alga plectonema boryanum by the luciferase assay for ATP

    Science.gov (United States)

    Bush, V. N.

    1974-01-01

    Plectonema boryanum is a filamentous blue green alga. Blue green algae have a procaryotic cellular organization similar to bacteria, but are usually obligate photoautotrophs, obtaining their carbon and energy from photosynthetic mechanism similar to higher plants. This research deals with a comparison of three methods of quantitating filamentous populations: microscopic cell counts, the luciferase assay for ATP and optical density measurements.

  12. Modeling the Role of Zebra Mussels in the Proliferation of Blue-green Algae in Saginaw Bay, Lake Huron

    Science.gov (United States)

    Under model assumptions from Saginaw Bay 1991, selective rejection of blue-green algae by zebra mussels appears to be a necessary factor in the enhancement of blue-green algae production in the presence of zebra mussels. Enhancement also appears to depend on the increased sedime...

  13. Endolithic blue-green algae in the dry valleys: primary producers in the antarctic desert ecosystem.

    Science.gov (United States)

    Friedmann, E I; Ocampo, R

    1976-09-24

    Endolithic unicellular blue-green algae occur under the surface of orthoquartzite rocks in the dry valleys of southern Victoria Land, Antarctica. This report of primary producers in the Antarctic desert ecosystem suggests that, in future efforts to detect life in extraterrestrial (for example, martian) environments, scientists should consider the possible existence of endolithic life forms.

  14. Phycobiliproteins: A Novel Green Tool from Marine Origin Blue-Green Algae and Red Algae.

    Science.gov (United States)

    Chandra, Rashmi; Parra, Roberto; Iqbal, Hafiz M N

    2017-01-01

    Marine species are comprising about a half of the whole global biodiversity; the sea offers an enormous resource for novel bioactive compounds. Several of the marine origin species show multifunctional bioactivities and characteristics that are useful for a discovery and/or reinvention of biologically active compounds. For millennia, marine species that includes cyanobacteria (blue-green algae) and red algae have been targeted to explore their enormous potential candidature status along with a wider spectrum of novel applications in bio- and non-bio sectors of the modern world. Among them, cyanobacteria are photosynthetic prokaryotes, phylogenetically a primitive group of Gramnegative prokaryotes, ranging from Arctic to Antarctic regions, capable of carrying out photosynthesis and nitrogen fixation. In the recent decade, a great deal of research attention has been paid on the pronouncement of bio-functional proteins along with novel peptides, vitamins, fine chemicals, renewable fuel and bioactive compounds, e.g., phycobiliproteins from marine species, cyanobacteria and red algae. Interestingly, they are extensively commercialized for natural colorants in food and cosmetics, antimicrobial, antioxidant, anti-inflammatory, neuroprotective, hepatoprotective agents and fluorescent neo-glycoproteins as probes for single particle fluorescence imaging fluorescent applications in clinical and immunological analysis. However, a comprehensive knowledge and technological base for augmenting their commercial utilities are lacking. Therefore, this paper will provide an overview of the phycobiliproteins-based research literature from marine cyanobacteria and red algae. This review is also focused towards analyzing global and commercial activities with application oriented-based research. Towards the end, the information is also given on the potential biotechnological and biomedical applications of phycobiliproteins. Copyright© Bentham Science Publishers; For any queries, please

  15. Strong tolerance of blue-green alga Microcystis flos-aquae to very high pressure

    Science.gov (United States)

    Ono, F.; Nishihira, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Saigusa, M.; Matsushima, Y.; Yamazaki, D.; Ito, E.

    2015-09-01

    It was shown in our previous reports that a few spores of moss Venturiella could tolerate the very high pressure of 20 GPa for 30 min and germinated a protonema to the length of 30 μm. However, these spores did not grow any further, and disappeared at around 30 days of incubation after seeded. On the other hand, colonies of blue-green alga Microcystis flos-aquae came to appear about 76 days after the moss spores were seeded. Many of these colonies appeared at the places where the moss spores had disappeared. These colonies were formed by the algae that had adhered to the spore cases of the moss and survived after exposure to the very high pressure of 20 GPa. Though the appearance of the colonies of high pressure exposed algae was delayed by about 50 days compared with that of the control group which was not exposed to high pressure, there seems no difference in their shape and color from those of the control group. The pressure tolerance of blue-green alga is found to be enormously strong, and it can survive after exposure to the high pressure which corresponds to the depth of about 550-600 km from the surface of the Earth, just above the lower mantle.

  16. Cloning and sequencing of the ferredoxin gene of blue-green alga Anabaena siamensis

    Science.gov (United States)

    Li, Shou-Dong; Song, Li-Rong; Liu, Yong-Ding; Zhao, Jin-Dong

    1998-03-01

    The structure gene for ferredoxin, petFI, from Anabaena siamensis has been amplified by polymerase chain reaction(PCR) and cloned into cloning vector pGEM-3zf(+). The nucleotide sequence of petFI has been determined with silver staining sequencing method. There is 96.8% homology between coding region of petFI from A. siamensis and that of petFI from A. sp. 7120. Amino acid sequences of seven strains of blue-green algae are compared.

  17. Langmuir-Blodgett film of phycobilisomes from blue-green alga Spirulina platensis.

    Science.gov (United States)

    Chen, Chao; Zhang, Yu-Zhong; Chen, Xiu-Lan; Zhou, Bai-Cheng; Gao, Hong-Jun

    2003-10-01

    The phycobilisomes were isolated from blue-green alga Spirulina platensis, and could form monolayer film at air/water interface. The monolayer film of phycobilisomes was transferred to newly cleaved mica, and coated with gold. Scanning tunneling microscope was used to investigate the structure of the Langmuir-Blodgett film of phycobilisomes. It was shown that phycobilisomes in the monolayer arrayed in rows with core attaching on the substrate surface and rods radiating towards the air phase, this phenomenon was similar to the arrangement of phycobilisomes on cytoplasmic surface of thylakoid membrane in vivo. The possible applications of the Langmuir-Blodgett film of phycobilisomes were also discussed.

  18. Distribution of blue-green algae (Cyanophyta in streams of Mt. Stara planina: Serbia

    Directory of Open Access Journals (Sweden)

    Simić Snežana B.

    2002-01-01

    Full Text Available Distribution of blue-green algae was studied at 14 sites along five streams in the Stara Planina mountains. Algological samples were taken from the community of benthos and periphyton in the spring (March-May 1991, summer (June-August 1991, August 1996, July 1997, and autumn (September-November 1991, September 1997. Algae of the classes Chamaesiphonophyceae (species of the genus Chamaesiphon and Hormogoniophyceae (species of the genera Symploca, Phormidium, Oscillatoria, Schizothrix, Nostoc, Rivularia Homoeothrix, Tolypothrix, and Plectonema were recorded. The species Chamaesiphon cylindricus, Symploca radians, Phormidium coutinhoi, Nostoc coeruleum, Homoeothrix janthina, Plectonema thomasinianum, and Tolypothrix distorta were registered herein first time in Serbia. Occurrence of blue-green algae in highland brooks and rivers of the Stara Planina mountains was monitored in relation to a large number of abiotic factors e.g. altitude above level, stream dimensions (width and depth, substrate bottom type (%, current flow rate, water temperature and pH oxygen concentration, concentrations of nitrates and phosphates, and BOD5, using Principal Coordinates analysis (PCX.

  19. Development of a UV laser-induced fluorescence lidar for monitoring blue-green algae in Lake Suwa.

    Science.gov (United States)

    Saito, Yasunori; Takano, Kengo; Kobayashi, Fumitoshi; Kobayashi, Kazuki; Park, Ho-Dong

    2014-10-20

    We developed a UV (355 nm) laser-induced fluorescence (LIF) lidar for monitoring the real-time status of blue-green algae. Since the fluorescence spectrum of blue-green algae excited by 355 nm showed the specific fluorescence at 650 nm, the lidar was designed to be able to detect the 650 nm fluorescence as a surveillance method for the algae. The usefulness was confirmed by observation at Lake Suwa over four years (2005-2008). The detection limit of the LIF lidar was 16.65 mg/L for the blue-green algae, which is the range of concentrations in the safe level set by the World Health Organization.

  20. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms

    Energy Technology Data Exchange (ETDEWEB)

    Uma Suganya, K.S. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Govindaraju, K., E-mail: govindtu@gmail.com [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Ganesh Kumar, V.; Stalin Dhas, T.; Karthick, V. [Centre for Ocean Research, Sathyabama University, Chennai 600 119 (India); Singaravelu, G. [Nanoscience Division, Department of Zoology, Thiruvalluvar University, Vellore 632115 (India); Elanchezhiyan, M. [Department of Microbiology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600113 (India)

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet–visible (UV–vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ∼ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. - Highlights: • Size controlled synthesis of gold nanoparticles from blue green alga Spirulina platensis • Stability of gold nanoparticles at different temperatures • Potent antibacterial efficacy against Gram positive organisms.

  1. Biochemical Basis of Obligate Autotrophy in Blue-Green Algae and Thiobacilli

    Science.gov (United States)

    Smith, Arnold J.; London, Jack; Stanier, Roger Y.

    1967-01-01

    Differential rates of incorporation of sugars, organic acids, and amino acids during autotrophic growth of several blue-green algae and thiobacilli have been determined. In obligate autotrophs (both blue-green algae and thiobacilli), exogenously furnished organic compounds make a very small contribution to cellular carbon; acetate, the most readily incorporated compound of those studied, contributes about 10% of newly synthesized cellular carbon. In Thiobacillus intermedius, a facultative chemoautotroph, acetate contributes over 40% of newly synthesized cellular carbon, and succinate and glutamate almost 90%. In the obligate autotrophs, carbon from pyruvate, acetate, and glutamate is incorporated into restricted groups of cellular amino acids, and the patterns of incorporation in all five organisms are essentially identical. These patterns suggest that the tricarboxylic acid cycle is blocked at the level of α-ketoglutarate oxidation. Enzymatic analyses confirmed the absence of α-ketoglutarate dehydrogenase in the obligate autotrophs, and also revealed that they lacked reduced nicotinamide adenine dinucleotide oxidase, and had extremely low levels of malic and succinic dehydrogenase. These enzymatic deficiencies were not manifested by the two facultative chemoautotrophs examined. On the basis of the data obtained, an interpretation of obligate autotrophy in both physiological and evolutionary terms has been developed. PMID:4963789

  2. Studies on the proteins of mass-cultivated, blue-green alga (Spirulina platensis)

    Energy Technology Data Exchange (ETDEWEB)

    Annusuyadevi, M.; Subbulakshmi, G.; Madhair' devi, K.; Venkalaramein, L.V.

    1981-05-01

    The characteristics of the protein of fresh-water, mass-cultured Spirulina platensis have been studied. The solubility of this algal protein in water and various aqueous solvents has been estimated. The total protein content of the blue-green algae was approximately 50-55% of which nearly 9.9% was nonprotein nitrogen. About 80% of the total protein nitrogen can be extracted by three successive extractions with water. Ths isoelectric point of this algal protein is found to be 3.0. The total proteins were characterized physicochemically by standard techniques. In the ultracentrifuge total proteins resolve into two major components with S20w values of 2.6 and 4.7 S. The polyacrylamide gel electrophoretic pattern of the total protein showed seven bands including three prominent ones. The in vitro digestibility of the total protein of fresh algae was found to be 85% when assayed with a pepsin-pancreatin system.

  3. Production and utilization of the blue-green alga Spirulina in India. [Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Becker, E.W.; Venkataraman, L.V.

    1984-01-01

    Initiated by Indo-German cooperation on large-scale cultivation of micro-algae, aspects of production, processing and utilization of the blue-green alga (cyanobacterium) Spirulina platensis were studied with regard to Indian conditions, with the immediate objective of utilising the algal biomass at rural levels as animal feed. Thus, simple techniques involving less energy and capital were tested for their suitability. The algal material produced was analyzed for its chemical composition, nutritional quality, supplementary value and toxicological safety. The results obtained demonstrated that Spirulina represents an unobjectionable source of unconventional protein of good quality. Short-term feeding tests with rats did not reveal any negative symptoms which would impair the utilization of Spirulina as food or feed.

  4. Diurnal variation in n(2) fixation and photosynthesis by aquatic blue-green algae.

    Science.gov (United States)

    Peterson, R B; Friberg, E E; Burris, R H

    1977-01-01

    Rates of (14)CO(2) fixation, O(2) evolution, and N(2) fixation (acetylene reduction) by natural populations of blue-green algae recovered from Lake Mendota were measured at frequent intervals between sunrise and sunset. Photosynthesis and N(2) fixation were depressed during midday when light intensity was greatest. As the light intensity rose, most of the algal population migrated to deeper, light-limited waters where radiation damage would be diminished. As the relative rate of N(2) fixation compared to CO(2) fixation increases with depth, it is suggested that the algae maintain balanced growth by migrating vertically via buoyancy regulation. High concentrations of dissolved O(2) in lake water may inhibit N(2) fixation by enhancing photorespiration. Several factors such as photosynthetic rate, light intensity, dissolved O(2), species composition, and vertical and horizontal migration all affect observed rates of in situ N(2) fixation.

  5. Purification and characterization of phycocyanin from the blue-green alga Aphanizomenon flos-aquae.

    Science.gov (United States)

    Benedetti, Serena; Rinalducci, Sara; Benvenuti, Francesca; Francogli, Sonia; Pagliarani, Silvia; Giorgi, Luca; Micheloni, Mauro; D'Amici, Gian Maria; Zolla, Lello; Canestrari, Franco

    2006-03-20

    Aphanizomenon flos-aquae (AFA) is a blue-green alga and represents a nutrient-dense food source. In this study the presence of phycocyanin (PC), a blue protein belonging to the photosynthetic apparatus, has been demonstrated in AFA. An efficient method for its separation has been set up: PC can be purified by a simple single step chromatographic run using a hydroxyapatite column (ratio A620/A280 of 4.78), allowing its usage for health-enhancing properties while eliminating other aspecific algal components. Proteomic investigation and HPLC analysis of purified AFA phycobilisomes revealed that, contrary to the well-characterized Synechocystis and Spirulina spp., only one type of biliprotein is present in phycobilisomes: phycocyanins with no allo-phycocyanins. Two subunit polypeptides of PC were also separated: the beta subunit containing two bilins as chromophore and the alpha subunit containing only one.

  6. Mössbauer study of cobalt and iron in the cyanobacterium (blue green alga)

    Science.gov (United States)

    Ambe, Shizuko

    1990-07-01

    Mössbauer emission and absorption studies have been performed on cobalt and iron in the cyanobacterium (blue-green alga). The Mössbauer spectrum of the cyanobacterium cultivated with57Co is decomposed into two doublets. The parameters of the major doublet are in good agreement with those of cyanocobalamin (vitamin B12) labeled with57Co. The other minor doublet has parameters close to those of Fe(II) coordinated with six nitrogen atoms. These suggest that cobalt is used for the biosynthesis of vitamin B12 or its analogs in the cyanobacterium. The spectra of the cyanobacterium grown with57Fe show that iron is in the high-spin trivalent state and possibly in the form of ferritin, iron storage protein.

  7. Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.

    Science.gov (United States)

    Suganya, K S Uma; Govindaraju, K; Kumar, V Ganesh; Dhas, T Stalin; Karthick, V; Singaravelu, G; Elanchezhiyan, M

    2015-02-01

    Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet-visible (UV-vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ~ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus.

  8. Calcium spirulan, an inhibitor of enveloped virus replication, from a blue-green alga Spirulina platensis.

    Science.gov (United States)

    Hayashi, T; Hayashi, K; Maeda, M; Kojima, I

    1996-01-01

    Bioactivity-directed fractionation of a hot H2O extract from a blue-green alga Spirulina platensis led to the isolation of a novel sulfated polysaccharide named calcium spirulan (Ca-SP) as an antiviral principle. This polysaccharide was composed of rhamnose, ribose, mannose, fructose, galactose, xylose, glucose, glucuronic acid, galacturonic acid, sulfate, and calcium. Ca-SP was found to inhibit the replication of several enveloped viruses, including Herpes simplex virus type 1, human cytomegalovirus, measles virus, mumps virus, influenza A virus, and HIV-1. It was revealed that Ca-SP selectively inhibited the penetration of virus into host cells. Retention of molecular conformation by chelation of calcium ion with sulfate groups was suggested to be indispensable to its antiviral effect.

  9. Energy transfer from carotenoids to chlorophyll in blue-green, red and green algae and greening bean leaves

    NARCIS (Netherlands)

    Goedheer, J.C.

    1969-01-01

    From fluorescence action spectra, fluorescence spectra and absorption spectra measured at room temperature and at 77 °K of light petroleum (b.p. 40–60°)-treated and normal chloroplasts, it is concluded that: 1. 1. In blue-green and red algae energy transfer from β-carotene to chlorophyll occurs in

  10. Extraction of nutraceuticals from Spirulina (blue-green alga): A bioorganic chemistry practice using thin-layer chromatography.

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J; Luna-Freire, Kristerson R; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together current research, theory, and practice, and always in accordance with pedagogical ideas.

  11. Energy transfer from carotenoids to chlorophyll in blue-green, red and green algae and greening bean leaves

    NARCIS (Netherlands)

    Goedheer, J.C.

    1969-01-01

    From fluorescence action spectra, fluorescence spectra and absorption spectra measured at room temperature and at 77 °K of light petroleum (b.p. 40–60°)-treated and normal chloroplasts, it is concluded that: 1. 1. In blue-green and red algae energy transfer from β-carotene to chlorophyll occurs in

  12. Extraction of Nutraceuticals from Spirulina (Blue-Green Alga): A Bioorganic Chemistry Practice Using Thin-layer Chromatography

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J.; Luna-Freire, Kristerson R.; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together…

  13. Extraction of Nutraceuticals from Spirulina (Blue-Green Alga): A Bioorganic Chemistry Practice Using Thin-layer Chromatography

    Science.gov (United States)

    Herrera Bravo de Laguna, Irma; Toledo Marante, Francisco J.; Luna-Freire, Kristerson R.; Mioso, Roberto

    2015-01-01

    Spirulina is a blue-green alga (cyanobacteria) with high nutritive value. This work provides an innovative and original approach to the consideration of a bioorganic chemistry practice, using Spirulina for the separation of phytochemicals with nutraceutical characteristics via thin-layer chromatography (TLC) plates. The aim is to bring together…

  14. Ecosystem manipulation for increasing biological N2 fixation by blue-green algae (CYANOBACTERIA) in lowland rice fields

    OpenAIRE

    Grant, I.F.; Roger, Pierre-Armand; Watanabe, I.

    1986-01-01

    An introduction to the soil/floodwater ecosystem of lowland rice fields is given. Two primary consumers are particularly important in limiting the growth and N2-fixing activities of blue-green algae in irrigated rice ; the OSTRACODA (Class CRUSTACEA) and the PULMONATA (MULUSCA). Control of grazing by neem seeds AZADIRACHTA INDICA A. Juss and cultural practices enhanced BGA biomass and increased N2-fixation ten fold. Significant increases in rice grain protein occur if heterocystous algae bloo...

  15. The influence of nitrogen on heterocyst production in blue-green algae

    Science.gov (United States)

    Ogawa, Roann E.; Carr, John F.

    1969-01-01

    A series of experiments on heterocyst production in Anabaena variabilis provides some strong indirect evidence for the role of heterocysts in nitrogen fixation. Of the algae tested (Anabaena variabilis, A. inaequalis, A. cylindrica, A. flos-aquae, Tolypothrix distorta, Gloeotrichia echinulata, Aphanizomenon flos-aquae, Oscillatoria sp., and Microcystis aeruginosa), only those with heterocysts grew in a nitrate-free medium. Growth in the nitrate-free medium was accompanied by an increase in heterocysts. Heterocyst formation in A. variabilis was evident 24 hr after transfer from a nitrate-containing to a nitrate-free medium. The number of heterocysts was altered by changes in the nitrogen source. Numbers were lowest when NH4-N was used as a nitrogen source and highest when nitrogen (N2-N) was derived from the atmosphere. Heterocyst numbers could also be regulated by controlling the concentration of NO3-N in the medium. Heterocyst production depended on the absence of combined nitrogen and the presence of phosphate. Data are presented on the occurrence of blue-green algae (with heterocysts) in Lake Erie and the environmental conditions apparently necessary for them to become dominant.

  16. BIOGENESIS OF THYLAKOID MEMBRANES WITH RECONSTRUCTION OF CHLOROPHYLL-PROTEIN COMPLEXES IN DELETION-MUTANT OF ORF469 IN BLUE-GREEN ALGA

    Institute of Scientific and Technical Information of China (English)

    WuQingyu; WangRuiyong; XuHong; WireVermaas

    1997-01-01

    The transformable blue green alga is used productively for mutation and deletion studies to provide functional information regarding photosynthetic reaction center complexes. We wish to take the application of transformable blue-green algal systems one step further ,and set out the

  17. Requirement of low oxidation-reduction potential for photosynthesis in a blue-green alga (Phormidium sp.).

    Science.gov (United States)

    Weller, D; Doemel, W; Brock, T D

    1975-06-20

    Photosynthesis in a Phormidium species which forms dense conical-shaped structures in thermal springs is strongly inhibited by aeration but is stimulated by sulfide and other agents (cysteine, thioglycolate, sulfite) which lower the oxidation-reduction potential. The compact structures which this alga forms in nature may restrict oxygen penetration from the enviroment so that the anaerobic or microaerophilic conditions necessary ofr photosynthesis can develop. The alga may be defective in a regulatory mechanism that controls the reoxidation of reduced pyridine nucleotides formed during photosynthesis. It is suggested that other mat-forming and benthic blue-green algae may also prefer anaerobib conditions for growth and photosynthesis.

  18. Degradation of tricyclazole: Effect of moisture, soil type, elevated carbon dioxide and Blue Green Algae (BGA).

    Science.gov (United States)

    Kumar, Naveen; Mukherjee, Irani; Sarkar, Bipasa; Paul, Ranjit Kumar

    2017-01-05

    Pesticide persistence and degradation in soil are influenced by factors like soil characteristics, light, moisture etc. Persistence of tricyclazole was studied under different soil moisture regimes viz., dry, field capacity and submerged in two different soil types viz., Inceptisol and Ultisol from Delhi and Karnataka, respectively. Tricyclazole dissipated faster in submerged (t1/2 160.22-177.05d) followed by field capacity (t1/2 167.17-188.07d) and dry (t1/2 300.91-334.35d) in both the soil types. Half-life of tricyclazole in Delhi field capacity soil amended with Blue Green Algae (BGA), was 150.5d as compared to 167.1d in unamended soil. In Karnataka soil amended with BGA the half-lives were 177.0d compared to 188.0d in unamended soil, indicating that BGA amendment enhanced the rate of dissipation of in both the selected soils. Tricyclazole was found to be stable in water over a pH range of 3-9, the half life in paddy field was 60.20d and 5.47d in paddy soil and paddy water, respectively. Statistical analysis and Duncan's Multiple Range Test (DMRT) revealed significant effect of moisture regime, organic matter and atmospheric CO2 level on dissipation of tricyclazole from soil and pH of water (at 95% confidence level p<0.0001). Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Colony development and physiological characterization of the edible blue-green alga, Nostoc sphaeroides (Nostocaceae, Cyanophyta)

    Institute of Scientific and Technical Information of China (English)

    Zhongyang Deng; Qiang Hu; Fan Lu; Guoxiang Liu; Zhengyu Hu

    2008-01-01

    The edible blue-green alga,Nostoc sphaeroides Kützing,is able to form microcolorties and spherical macrocolonies.It has been used as a potent herbal medicine and dietary supplement for centuries because of its nutraceutical and pharmacological benefits.However,lim-ited information is available on the development of the spherical macrocolonies and the environmental factors that affect their structure.This report described the morphogenesis of N.Sphaeroides from single trichomes to macrocolonies.During the process,most structural features of macrocolonies of various sizes were dense maculas,rings,the compact core and the formation of liquid core;and the filaments within the macrocolonies showed different lengths and arrays depending on the sizes of macrocolonies.Meanwhile temperature and light intensity also strongly affected the internal structure of macrocolonies.As microcolonies further increased in size to form 30 mm mac-rocolonies,the colonies differentiated into distinct outer,middle and inner layers.The filaments of the outer layer showed higher max-imum photosynthetic rates,higher light saturation point,and higher photosynthetic efficiency than those of the inner layer;whereas the filaments of the inner layer had a higher content of chlorophyll a and phycobiliproteins than those of the outer layer.The results obtained in this study were important for the mass cultivation of N.Sphaeroides as a nutraceutical product.

  20. Blue-Green Algae Inhibit the Development of Atherosclerotic Lesions in Apolipoprotein E Knockout Mice.

    Science.gov (United States)

    Ku, Chai Siah; Kim, Bohkyung; Pham, Tho X; Yang, Yue; Wegner, Casey J; Park, Young-Ki; Balunas, Marcy; Lee, Ji-Young

    2015-12-01

    Hyperlipidemia and inflammation contribute to the development of atherosclerotic lesions. Our objective was to determine antiatherogenic effect of edible blue-green algae (BGA) species, that is, Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), in apolipoprotein E knockout (ApoE(-/-)) mice, a well-established mouse model of atherosclerosis. Male ApoE(-/-) mice were fed a high-fat/high-cholesterol (HF/HC, 15% fat and 0.2% cholesterol by wt) control diet or a HF/HC diet supplemented with 5% (w/w) of NO or SP powder for 12 weeks. Plasma total cholesterol (TC) and triglycerides (TG) were measured, and livers were analyzed for histology and gene expression. Morphometric analysis for lesions and immunohistochemical analysis for CD68 were conducted in the aorta and the aortic root. NO supplementation significantly decreased plasma TC and TG, and liver TC, compared to control and SP groups. In the livers of NO-fed mice, less lipid droplets were present with a concomitant decrease in fatty acid synthase protein levels than the other groups. There was a significant increase in hepatic low-density lipoprotein receptor protein levels in SP-supplemented mice than in control and NO groups. Quantification of aortic lesions by en face analysis demonstrated that both NO and SP decreased aortic lesion development to a similar degree compared with control. While lesions in the aortic root were not significantly different between groups, the CD68-stained area in the aortic root was significantly lowered in BGA-fed mice than controls. In conclusion, both NO and SP supplementation decreased the development of atherosclerotic lesions, suggesting that they may be used as a natural product for atheroprotection.

  1. Hypocholesterolemic effect of Nostoc commune var. sphaeroides Kützing, an edible blue-green alga.

    Science.gov (United States)

    Rasmussen, Heather E; Blobaum, Kara R; Jesch, Elliot D; Ku, Chai Siah; Park, Young-Ki; Lu, Fan; Carr, Timothy P; Lee, Ji-Young

    2009-10-01

    Intake of an edible blue-green alga Nostoc commune var. sphaeroides Kützing (N. Commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect have not been elucidated. To elucidate the mechanisms underlying the cholesterol-lowering effect of N. commune in mice. Male C57BL/6J mice were fed the AIN-93 M diet supplemented with 0 or 5% (wt/wt) dried N. Commune for 4 weeks. Lipid levels in the plasma and liver, intestinal cholesterol absorption and fecal sterol excretion were measured. Expression of hepatic and intestinal genes involved in cholesterol metabolism was evaluated by quantitative realtime PCR. N. commune supplementation significantly reduced total plasma cholesterol and triglyceride concentrations by approximately 20% compared to controls. Intestinal cholesterol absorption was significantly decreased, while fecal neutral sterol output was significantly increased in N. commune-fed mice. mRNA levels of the cholesterol transporters such as Niemann Pick C1 Like 1, scavenger receptor class B type 1, ATP-binding cassette transporters G5 and A1 in small intestine were not significantly different between two groups. Hepatic lipid contents including total cholesterol, triglyceride and free cholesterol in N. commune-fed mice were not significantly altered. However, the expression of cholesterol modulating genes including sterol regulatory element binding protein-2 and 3-hydroxy-3-methylglutaryl coenzyme A reductase were significantly increased in mice fed N. commune. N. commune supplementation exerted a hypocholesterolemic effect in mice, largely in part, by reducing intestinal cholesterol absorption and promoting fecal neutral sterol excretion.

  2. Interactions of carbon and nitrogen metabolism with changing light intensity in natural populations and cultures of planktonic blue-green algae

    Energy Technology Data Exchange (ETDEWEB)

    Ward, A.K.

    1978-01-01

    This study dealt with the factors contributing to the occurrence of blue-green algae in the plankton of lakes. Blue-green algal populations were examined in two different aquatic systems, moderately productive Lawrence Lake and hypereutrophic Wintergreen Lake, with regard to inorganic nitrogen source, light intensity and regime, and species of blue-green algae present. In order to understand the relationship between light and nitrogen source better among natural populations, representative species of blue-green algae, including isolates of Aphanizomenon flos-aquae, Microcystis aeruginosa, and Anabaena flos-aquae, were grown in laboratory cultures under continuously high, variable, and continuously low light at intensities similar to those in the lakes.

  3. Reclamation with blue-green algae: changes in nucleic acids, protein and nitrogen content of algae exposed to solid waste of a chlor-alkali factory

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, B.B.; Nanda, D.R.; Misra, B.N.

    1985-01-01

    During an attempt at the possible reclamation of solid waste from a chlor-alkali factory by blue-green algae, the effects of the solid waste on biochemical variables were studied. DNA, RNA, protein, and algal nitrogen content of the algal material showed a significant decrease with increase in time and also solid waste concentration. An increase in RNA/DNA ratio and a decrease in protein/RNA ratio were also observed. Algae accumulated appreciable amounts of mercury from the waste, showing dependence on both concentration and time. Significant correlations were obtained between mercury uptake and concentrations of the waste and between different combinations of algae and mercury uptake.

  4. The occurrence and biosynthesis of gamma-linolenic acid in a blue-green alga,Spirulina platensis.

    Science.gov (United States)

    Nichols, B W; Wood, B J

    1968-01-01

    The acyl-lipid and fatty acid composition of six blue-green algae, namely,Spirulina platensis, Myxosarcina chroococcoides, Chlorogloea fritschii, Anabaena cylindrica, Anabaena flos-aquae, and Mastigocladus laminosus is reported.All contain major proportions of mono-and digalactosyl diglyceride, sulfoquinovosyl diglyceride, and phosphatidyl glycerol, but none possess lecithin, phophatidyl ethanolamine, or phosphatidyl inositol. Trans-3-hexadecenoic acid was absent from all extracts.The analyses provide further evidence that there is no general chemical or physical requirement for any specific fatty acid in photosynthesis. S. platensis is unique among photoautotrophic organisms so far studied, containing major quantities of gamma-linolenic acid (6,9,12-octadecatrienoic acid). This acid is synthesized by the alga by direct desaturation of linoleic acid and is primarily located in the mono- and digalactosyl diglyceride fractions.The possible phylogenetic relationship betweenS. platensis and other plant forms is discussed.

  5. Bioaccumulation of Cr(III ions by Blue Green-alga Spirulina sp. Part II. Mathematical Modeling

    Directory of Open Access Journals (Sweden)

    Katarzyna Chojnacka

    2007-01-01

    Full Text Available In the present paper bioaccumulation of Cr(III ions by blue-green algae Spirulina sp. is discussed. We found that the process consisted of two stages: passive in which Cr(III ions are bound to the surface of cells, identical with biosorption and active, metabolism-dependent, in which Cr(III ions are transported into the cellular interior. The passive stage occurs in both living and non-living cells and the active only in living biomass. Two distinctive mathematical models of the process were proposed. The first was physical model basing on the identified mechanism of the process. In the second model, artificial neural networks were proposed.

  6. Isolation and characterization of lipopolysaccharides from cell walls of blue-green algae of the genus Phormidium.

    Science.gov (United States)

    Mikheyskaya, L V; Ovodova, R G; Ovodov, Y S

    1977-04-01

    Lipopolysaccharide (LPS) fractions were isolated from three species of blue-green algae of the genus Phormidium, namely, P. africanum, P. laminosum, and P. uncinatum, by using a phenol-water procedure followed by exhaustive extraction with ammonium oxalate. The materials obtained were shown to be closely related biochemically. Nearly 60% of the LPS consisted of the polysaccharides galactose, glucose, mannose, xylose, arabinose, and rhamnose and an unidentified, fast-moving sugar residue. In addition, glucosamine, galactosamine, and 2-keto-3-deoxyoctonate were detected. Oleic, stearic, and palmitic acids were found in the hydrolysate of the lipid component, which averaged 1.5% of the LPS. Concomitantly, the protein component (7 to 20%) was shown to contain the following amino acids: aspartic acid, threonine, serine glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, and arginine. Whole cells, as well as the LPS, of Phormidium possessed antigenic properties.

  7. Occurrence and purification on microcystis species. Toxicology of blue-green algae toxins; Aoko/sono hassei to joka taisaku. Aoko no yudoku busshitsu no dokusei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, K. [National Inst. for Environmental Studies, Tsukuba (Japan)

    1994-09-10

    In recent years the blue-green algae has occurred tremendously in the lakes at every places in the world, and therefore it has become a social problem. Especially in Australia and New Zealand, the damages not only on the cattles and the wild animals, they have commenced to develop up to the health problems of the residents. By a progress of the study of the blue-green algae toxins, a structure and toxicity of many blue-green algae toxins have been made clear. The microcystin which it one of them, is a hepatic toxin produced by the microcystis, anabaena and oscillatoria. By the way, because it was made clear recently by a study done by the National Cancer Center that it had a carcinogenesis promotion action, its action has been paid attention over again. In the blue-green algae toxins, besides the microcystin it is made clear that there are the nervus toxins such as the anatoxin-a and anatoxin-a (s) produced by anabaena, the aphantoxin produced by aphanizomenon and so forth. In this paper, as for the toxicity manifestation mechanism of the microcystin which is thought to become a point at issue in Japan, an information up to date is introduced. 17 refs., 2 figs.

  8. Artificial microfossils - Experimental studies of permineralization of blue-green algae in silica.

    Science.gov (United States)

    Oehler, J. H.; Schopf, J. W.

    1971-01-01

    A technique has been developed to artificially fossilize microscopic algae in crystalline silica under conditions of moderately elevated temperature and pressure. The technique is designed to simulate geochemical processes thought to have resulted in the preservation of organic microfossils in Precambrian bedded cherts. In degree of preservation and mineralogic setting, the artificially permineralized microorganisms are comparable to naturally occurring fossil algae.

  9. Effects of blue-green algae extracts on the proliferation of human adult stem cells in vitro: a preliminary study.

    Science.gov (United States)

    Shytle, Douglas R; Tan, Jun; Ehrhart, Jared; Smith, Adam J; Sanberg, Cyndy D; Sanberg, Paul R; Anderson, Jerry; Bickford, Paula C

    2010-01-01

    Adult stem cells are known to have a reduced restorative capacity as we age and are more vulnerable to oxidative stress resulting in a reduced ability of the body to heal itself. We have previously reported that a proprietary nutraceutical formulation, NT-020, promotes proliferation of human hematopoietic stem cells in vitro and protects stem cells from oxidative stress when given chronically to mice in vivo. Because previous reports suggest that the blue green algae, Aphanizomenon flos-aquae (AFA) can modulate immune function in animals, we sought to investigate the effects of AFA on human stem cells in cultures. Two AFA products were used for extraction: AFA whole (AFA-W) and AFA cellular concentrate (AFA-C). Water and ethanol extractions were performed to isolate active compounds for cell culture experiments. For cell proliferation analysis, human bone marrow cells or human CD34+ cells were cultured in 96 well plates and treated for 72 hours with various extracts. An MTT assay was used to estimate cell proliferation. We report here that the addition of an ethanol extract of AFA-cellular concentrate further enhances the stem cell proliferative action of NT-020 when incubated with human adult bone marrow cells or human CD34+ hematopoietic progenitors in culture. Algae extracts alone had only moderate activity in these stem cell proliferation assays. This preliminary study suggests that NT-020 plus the ethanol extract of AFA cellular concentrate may act to promote proliferation of human stem cell populations.

  10. Anti-cancer effects of blue-green alga Spirulina platensis, a natural source of bilirubin-like tetrapyrrolic compounds.

    Science.gov (United States)

    Koníčková, Renata; Vaňková, Kateřina; Vaníková, Jana; Váňová, Kateřina; Muchová, Lucie; Subhanová, Iva; Zadinová, Marie; Zelenka, Jaroslav; Dvořák, Aleš; Kolář, Michal; Strnad, Hynek; Rimpelová, Silvie; Ruml, Tomáš; J Wong, Ronald; Vítek, Libor

    2014-01-01

    Spirulina platensis is a blue-green alga used as a dietary supplement because of its hypocholesterolemic properties. Among other bioactive substances, it is also rich in tetrapyrrolic compounds closely related to bilirubin molecule, a potent antioxidant and anti-proliferative agent. The aim of our study was to evaluate possible anticancer effects of S. platensis and S. platensis-derived tetrapyrroles using an experimental model of pancreatic cancer. The anti-proliferative effects of S. platensis and its tetrapyrrolic components [phycocyanobilin (PCB) and chlorophyllin, a surrogate molecule for chlorophyll A] were tested on several human pancreatic cancer cell lines and xenotransplanted nude mice. The effects of experimental therapeutics on mitochondrial reactive oxygen species (ROS) production and glutathione redox status were also evaluated. Compared to untreated cells, experimental therapeutics significantly decreased proliferation of human pancreatic cancer cell lines in vitro in a dose-dependent manner (from 0.16 g•L-1 [S. platensis], 60 μM [PCB], and 125 μM [chlorophyllin], palga. Furthermore, it seems that dietary supplementation with this alga might enhance systemic pool of tetrapyrroles, known to be higher in subjects with Gilbert syndrome.

  11. Purification and characterization of cytochrome f-556.5 from the blue-green alga Spirulina platensis.

    Science.gov (United States)

    Böhme, H; Pelzer, B; Böger, P

    1980-10-03

    The membrane-bound cytochrome f-556.5 from the blue-green alga Spirulina platensis was purified to apparent homogeneity. Most of its properties are comparable to cytochrome f isolated from higher plants and green algae. It is clearly distinguishable from soluble cytochrome c-554, also present in Spirulina, which probably replaces the function of plastocyanin in photosynthetic electron transport. 1. The reduced form of cytochrome f exhibits an asymmetrical alpha-band with a maximum at 556.5 nm, and a pronounced shoulder at 550 nm. The beta-, gamma and delta-bands coincide with those described for Scenedesmus cytochrome f-553, with maxima at 524 (532), 422, 331 and a protein peak at 276 nm. The maximum of ferricytochrome f is at 410.5 nm; there is no indication of a weak 695 nm band, described for soluble c-type cytochromes. The purest preparations had a delta/protein-peak ratio of 0.8; the gamma/alpha ratio was 7.3. Formation of a pyridine hemochromogen with a maximum at 550 nm indicated a c-type cytochrome. The molar extinction coefficient at 556.5 nm is 30200, the differential extinction coefficient 21 500. 2. The molecular weight determined by gel filtration or SDS-polyacrylamide gel electrophoresis is 33 000 and 34 000, respectively. 3. The redox properties differ from those described for other cytochromes f isolated from green algae and higher plants: the midpoint redox potential is significantly more negative (+318 mV, pH 7.0) and from pH 6 to 10 no pH dependence is observed. 4. The isoelectric point was determined at pH 3.95, which is more acidic as compared to other cytochromes f. 5. Comparison of the amino acid composition indicated a distant relationship to higher plant cytochrome f and a closer relationship to cytochrome f from green algae.

  12. Promotive effect of se on the growth and antioxidation of a blue-green alga Spirulina maxima

    Science.gov (United States)

    Zhi-Gang, Zhou; Zhi-Li, Liu

    1998-12-01

    Cultures of a blue-green alga Spirulina maxima (Setch. et Gard.) Geitler with various concentrations of Se in Zarrouk's medium showed that not higher than 40 mg/L Se could promote its growth. The present experiments showed that S. maxima grown under normal conditions, has an oxidant stress defence system for hydrogen peroxide (H2O2) removal, which is the Halliwell-Asada pathway. When 4 to 20 mg/L Se was added to the algal medium, this pathway was replaced by a so-called Sestressed pathway containing GSH peroxidase (GSH-POD). As a result of the occurrence of both higher activity of GSH-POD and lower levels of hydroxyl radical (OH·), the Se-stressed pathway scavenged H2O2 so effectively that the growth of S. maxima was promoted by 4 to 20 mg/L Se. While GSH-POD activity of the alga disappeared at 40 mg/L Se, the recovery of ascorbate peroxidase was observed. The lower levels of ascorbic acid and GSH made the Halliwell-Asada pathway for scavenging H2O2 less effective, while the highest activity of catalase might be responsible in part for the H2O2 removal, causing the level of OH· in S. maxima grown at 40 mg/L Se to be much higher than the OH· level in this alga grown at 4 to 20 mg/L Se, but lower than that in the control. The OH· level changes caused the growth of S. maxima cultured at 40 mg/L Se to increase slightly to close to that of the control.

  13. Antioxidant properties of a novel phycocyanin extract from the blue-green alga Aphanizomenon flos-aquae.

    Science.gov (United States)

    Benedetti, Serena; Benvenuti, Francesca; Pagliarani, Silvia; Francogli, Sonia; Scoglio, Stefano; Canestrari, Franco

    2004-09-24

    Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga (cyanophyta) rich in phycocyanin (PC), a photosynthetic pigment with antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate the ability of a novel natural extract from AFA enriched with PC to protect normal human erythrocytes and plasma samples against oxidative damage in vitro. In red blood cells, oxidative hemolysis and lipid peroxidation induced by the aqueous peroxyl radical generator [2,2'-Azobis (2-amidinopropane) dihydrochloride, AAPH] were significantly lowered by the AFA extract in a time- and dose-dependent manner; at the same time, the depletion of cytosolic glutathione was delayed. In plasma samples, the natural extract inhibited the extent of lipid oxidation induced by the pro-oxidant agent cupric chloride (CuCl2); a concomitant increase of plasma resistance to oxidation was observed as evaluated by conjugated diene formation. The involvement of PC in the antioxidant protection of the AFA extract against the oxidative damage was demonstrated by investigating the spectral changes of PC induced by AAPH or CuCl2. The incubation of the extract with the oxidizing agents led to a significant decrease in the absorption of PC at 620 nm accompanied with disappearance of its blue color, thus indicating a rapid oxidation of the protein. In the light of these in vitro results, the potential clinical applications of this natural compound are under investigation.

  14. Quality evaluation of the edible blue-green alga Nostoc flagelliforme using a chlorophyll fluorescence parameter and several biochemical markers.

    Science.gov (United States)

    Gao, Xiang; Yang, Yiwen; Ai, Yufeng; Luo, Hongyi; Qiu, Baosheng

    2014-01-15

    Nostoc flagelliforme is an edible blue-green alga with herbal and dietary values. Due to the diminishing supply of natural N. flagelliforme and the large investment on the development of its cultivation technology, it is anticipated that artificially cultured N. flagelliforme will soon sustain the market supply. Once this change occurs, the storage-associated quality problem will become the focus of attention for future trade. In this paper, we used a chlorophyll fluorescence parameter, maximum quantum efficiency of Photosystem II (Fv/Fm), and several biomarkers to evaluate the quality of several N. flagelliforme samples. It was found that longer storage times resulted in darker coloured solutions (released pigments) and decreased amounts of chlorophyll a (Chl a) and water-soluble sugars (WSS). Additionally, a higher Fv/Fm value suggests better physiological recovery and quality. In actual application, determination of Fv/Fm would be the first step for evaluating the quality of N. flagelliforme, and the biochemical indexes would serve as good secondary markers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Free and total amino acid composition in blue-green algae.

    Science.gov (United States)

    Campanella, Luigi; Russo, Mario Vincenzo; Avino, Pasquale

    2002-04-01

    A simple, accurate and reproducible analytical method is described for the extraction and the simultaneous determination of 18 amino acids in different for geographical origin Spirulina alga samples using phenylisothiocianate as derivatizating agent in natural feed. The best experimental hydrolysis conditions have been studied varying the temperature, the time and the hydrolyzing reagent. The separation and the quantitative analysis of the by-products have been carried out by HPLC analysis and UV detection. An amino acid pattern is compared with that proposed by the Food Agriculture Organization (FAO) for an ideal protein and with those of some traditional feed.

  16. Hydrogen production from salt water by Marine blue green algae and solar radiation

    Science.gov (United States)

    Mitsui, A.; Rosner, D.; Kumazawa, S.; Barciela, S.; Phlips, E.

    1985-01-01

    Two marine bluegreen algae, Oscillatoria sp. Miami BG 7 and Synechococcus sp Miami 041511 have been selected as the result of over 10 years continuous and intensive effort of isolation, growth examination, and the screening of hydrogen photoproduction capability in this laboratory. Both strains photoproduced hydrogen for several days at high rates and a quantity of hydrogen was accumulated in a closed vessel. Overall hydrogen donor substance of the hydrogen photoproduction was found to be salt water. Using strain Miami BG 7, a two step method of hydrogen photoproduction from salt water was successfully developed and this was recycled several times over a one month period using both free cells and immobilized cells in both indoor and outdoor under natural sunlight. According to these experiments, a prototype floating hydrogen production system was designed for further development of the biosolar hydrogen production system.

  17. Hydrogen production from salt water by Marine blue green algae and solar radiation

    Science.gov (United States)

    Mitsui, A.; Rosner, D.; Kumazawa, S.; Barciela, S.; Phlips, E.

    1985-01-01

    Two marine bluegreen algae, Oscillatoria sp. Miami BG 7 and Synechococcus sp Miami 041511 have been selected as the result of over 10 years continuous and intensive effort of isolation, growth examination, and the screening of hydrogen photoproduction capability in this laboratory. Both strains photoproduced hydrogen for several days at high rates and a quantity of hydrogen was accumulated in a closed vessel. Overall hydrogen donor substance of the hydrogen photoproduction was found to be salt water. Using strain Miami BG 7, a two step method of hydrogen photoproduction from salt water was successfully developed and this was recycled several times over a one month period using both free cells and immobilized cells in both indoor and outdoor under natural sunlight. According to these experiments, a prototype floating hydrogen production system was designed for further development of the biosolar hydrogen production system.

  18. Food production and gas exchange system using blue-green alga (spirulina) for CELSS

    Science.gov (United States)

    Oguchi, Mitsuo; Otsubo, Koji; Nitta, Keiji; Hatayama, Shigeki

    1987-01-01

    In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself was conducted. Spirulina was cultivated in the 6 liter medium containing a sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated oxygen gas was separated using a polypropyrene porous hollow fiber membrane module. Through this experiment, oxygen gas (at a concentration of more than 46 percent) at a rate of 100 to approx. 150 ml per minute could be obtained.

  19. Food production and gas exchange system using blue-green alga (Spirulina) for CELSS

    Science.gov (United States)

    Oguchi, Mitsuo; Otsubo, Koji; Nitta, Keiji; Hatayama, Shigeki

    In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself has been conducted. Spirulina was cultivated in the 6-liter medium containing a sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated oxygen gas was separated using a polypropyrene porous hollow fiber membrane module. Through this experiment, oxygen gas (at a concentration of more than 46%) at a rate of 100 ~ 150 ml per minute could be obtained.

  20. Inhibition of enterovirus 71-induced apoptosis by allophycocyanin isolated from a blue-green alga Spirulina platensis.

    Science.gov (United States)

    Shih, Shin-Ru; Tsai, Kun-Nan; Li, Yi-Shuane; Chueh, Chuang-Chun; Chan, Err-Cheng

    2003-05-01

    Enterovirus 71 infection causes significant morbidity and mortality in children, yet there is no effective treatment. In this study, a protein-bound pigment, allophycocyanin purified from blue-green algae is first reported to exhibit anti-enterovirus 71 activity. Allophycocyanin neutralized the enterovirus 71-induced cytopathic effect in both human rhabdomyosarcoma cells and African green monkey kidney cells. The 50% inhibitory concentration of allophycocyanin for neutralizing the enterovirus 71-induced cytopathic effect was approximately 0.045 +/- 0.012 microM in green monkey kidney cells. The cytotoxic concentrations of allophycocyanin for rhabdomyosarcoma cells and African green monkey kidney cells were 1.653 +/- 0.003 microM and 1.521 +/- 0.012 microM, respectively. A plaque reduction assay showed that the concentrations of allophycocyanin for reducing plaque formation by 50% were approximately 0.056 +/- 0.007 microM and 0.101 +/- 0.032 microM, when allophycocyanin were added at the state of viral adsorption and post-adsorption, respectively. Antiviral activity was more efficient in cultures treated with allophycocyanin before viral infection compared with that in the cultures treated after infection. Allophycocyanin was also able to delay viral RNA synthesis in the infected cells and to abate the apoptotic process in enterovirus 71-infected rhabdomyosarcoma cells with evidence of characteristic DNA fragmentation, decreasing membrane damage and declining cell sub-G1 phase. It is concluded that allophycocyanin possesses antiviral activity and has a potential for development as an anti-enterovirus 71 agent.

  1. The photochemical and fluorescence properties of whole cells, spheroplasts and spheroplast particles from the blue-green alga Phormidium luridum.

    Science.gov (United States)

    Tel-or, E; Malkin, S

    1977-02-07

    The photochemical activities and fluorescence properties of cells, spheroplasts and spheroplast particles from the blue-green alga Phormidium luridum were compared. The photochemical activities were measured in a whole range of wavelengths and expressed as quantum yield spectra (quantum yield vs. wavelength). The following reactions were measured. Photosynthesis (O2 evolution) in whole cells; Hill reaction (O2 evolution) with Fe(CN)63- and NADP as electron acceptors (Photosystem II and photosystem II + Photosystem I reactions); electron transfer from reduced 2,6-dichlorophenolindophenol to diquat (Photosystem I reaction). The fluorescence properties were emission spectra, quantum yield spectra and the induction pattern. On the basis of comparison between the quantum yield spectra and the pigments compositions the relative contribution of each pigment to each photosystem was estimated. In normal cells and spheroplasts it was found that Photosystem I (Photosystem II) contains about 90% (10%) of the chlorophyll a, 90% (10%) of the carotenoids and 15% (85%) of the phycocyanin. In spheroplast particles there is a reorganization of the pigments; they loose a certain fraction (about half) of the phycocyanin but the remaining phycocyanin attaches itself exclusively to Photosystem I (!). This is reflected by the loss of Photosystem II activity, a flat quantum yield vs. wavelength dependence and a loss of the fluorescence induction. The fluorescence quantum yield spectra conform qualitatively to the above conclusion. More quantitative estimation shows that only a fraction (20--40%) of the chlorophyll of Photosystem II is fluorescent. Total emission spectrum and the ratio of variable to constant fluorescence are in agreement with this conclusion. The fluorescence emission spectrum shows characteristic differences between the constant and variable components. The variable fluorescence comes exclusively from chlorophyll a; the constant fluorescence is contributed, in addition

  2. Characterization and optimization of hydrogen production by a salt water blue-green alga Oscillatoria sp. Miami BG 7. II - Use of immobilization for enhancement of hydrogen production

    Science.gov (United States)

    Phlips, E. J.; Mitsui, A.

    1986-01-01

    The technique of cellular immobilization was applied to the process of hydrogen photoproduction of nonheterocystous, filamentous marine blue-green alga, Oscillatoria sp. Miami BG 7. Immobilization with agar significantly improved the rate and longevity of hydrogen production, compared to free cell suspensions. Rates of H2 production in excess of 13 microliters H2 mg dry/wt h were observed and hydrogen production was sustained for three weeks. Immobilization also provided some stabilization to environmental variability and was adaptable to outdoor light conditions. In general, immobilization provides significant advantages for the production and maintenance of hydrogen photoproduction for this strain.

  3. Antiferromagnetic exchange interaction in the two-iron-two-sulphur ferredoxin from the blue-green alga Spirulina maxima studied with a highly sensitive magnetic balance.

    Science.gov (United States)

    Petersson, L; Cammack, R; Rao, K K

    1980-03-26

    1. A highly sensitive magnetic balance of the Faraday type is described. 2. The magnetic susceptibility of the oxidized and reduced forms of the two-iron-two-sulphur ferredoxin from the blue-green alga Spirulina maxima has been measured over a wide temperature range. 3. The results can be interpreted within a simple model involving antiferromagnetically coupled iron atoms at the active site. The coupling, expressed as --J, is estimated to be 182 +/- 20/cm and 98 +5/-10 /cm for the oxidized and reduced forms, respectively.

  4. Concurrently inhibitory and allelopathic effects of allelochemicals secreted by Myriophyllum spicatum on growth of blue-green algae; Hozakinofusamo ga hoshutsushita areropashi busshitsu no aisorui ni taisuru fukugo sayo oyobi areropashi koka no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Nakai, S.; Inoue, Y.; Hosomi, M.; Murakami, A. [Tokyo Univ. of Agriculture and Technology, Tokyo (Japan)

    1998-10-10

    This paper describes effects of allelochemicals secreted by Myriophyllum spicatum on growth of blue-green algae. In order to propose an effective growth inhibitory method of blue-green algae with less impact on the ecosystem, biological interaction (allelopathy) between large aquatic plants and algae was investigated. Pyrogallic acid, gallic acid, catechin and ellagic acid secreted by M. spicatum provided growth inhibitory effects of blue-green algae (Microcyctis aeruginosa), individually. Complex interaction and allelopathic contribution of these four polyphenols were evaluated. By comparing the actual effects with the expected values, synergetic growth inhibitory effects were recognized by adding four polyphenols at the same time. Furthermore, growth inhibitory effects were evaluated for actual culture solution of M. spicatum and simulated culture solution made by four polyphenols. As a result, it was found that these four polyphenols relate to allelopathy of M. spicatum. 25 refs., 6 figs., 4 tabs.

  5. Technology for Anaerobic Fermentation of Blue-Green Algae%水华蓝藻厌氧发酵工艺技术研究

    Institute of Scientific and Technical Information of China (English)

    常志州; 杜静; 叶小梅; 严少华; 张振华

    2009-01-01

    以太湖水华蓝藻为底物,用改进的CSTR(continuous stirred tank reactor)工艺,研究了不同有机负荷条件下蓝藻厌氧发酵相关参数与蓝藻藻毒素的去除效果.结果表明:在(35±1) ℃条件下,逐步提高有机负荷,系统运行稳定,有机负荷最高可达3.53 kg·m-3·d-1,此时最大容积产气率达0.89 m3·m-3·d-1,COD去除率在70%左右,甲烷体积分数达60%以上.不同负荷条件下,出料中藻毒素(MC-RR、MC-LR)检测均为阴性,已达无害化处理要求,表明该工艺可以有效处置水华蓝藻,实现能量回收与无害化处理的目标.%Efficiency of the use of the modified continuous stirred tank reactor(CSTR) technology in anaerobic fermentation of blue-green algae collected from the Taihu Lake was studied under the different rates of organic loading.Results show that operation of the system at (35±1) ℃ remained stable with organic loading rate gradually increasing.After 65 days of operation,its organic loading could reach as high as 3.53 kg·m3·d-1,its gas producing rate well as high as 0.89 m3·m-3·d-1,its COD removal rate around 70%,and methane concentration of the biogas it produced over 60%.Test of the discharge from the system showed negative of microcystins (MC-RR or MC-LR) in all loading conditions.The findings suggest that the modified CSTR technology satisfies the requirement for efficient treatment of blue-green algae,while realizing the target of energy recovery and dehazardization of the blue-green algae.

  6. Mycosporine-like Amino Acids and Other Phytochemicals Directly Detected by High-Resolution NMR on Klamath (Aphanizomenon flos-aquae) Blue-Green Algae.

    Science.gov (United States)

    Righi, Valeria; Parenti, Francesca; Schenetti, Luisa; Mucci, Adele

    2016-09-07

    This study describes for the first time the use of high-resolution nuclear magnetic resonance (NMR) on Klamath (Aphanizomenon flos-aquae, AFA) blue-green algae directly on powder suspension. These algae are considered to be a "superfood", due to their complete nutritional profile that has proved to have important therapeutic effects. The main advantage of NMR spectroscopy is that it permits the detection of a number of metabolites all at once. The Klamath alga metabolome was revealed to be quite complex, and the most peculiar phytochemicals that can be detected directly on algae by NMR are mycosporine-like amino acids (porphyra-334, P334; shinorine, Shi) and low molecular weight glycosides (glyceryl β-d-galactopyranoside, GalpG; glyceryl 6-amino-6-deoxy-α-d-glucopyranoside, ADG), all compounds with a high nutraceutical value. The presence of cis-3,4-DhLys was revealed for the first time. This molecule could be involved in the anticancer properties ascribed to AFA.

  7. Comparative effects of the blue green algae Nodularia spumigena and a lysed extract on detoxification and antioxidant enzymes in the green lipped mussel (Perna viridis)

    Energy Technology Data Exchange (ETDEWEB)

    Davies, Warren R. [Department of Biotechnology and Environmental Biology, RMIT University, Melbourne, Victoria (Australia)]. E-mail: warren.davies@rmit.edu.au; Siu, William H.L. [Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong (China); Jack, Ralph W. [Department of Microbiology, University of Otago, Dunedin (New Zealand); Wu, Rudolf S.S. [Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong (China); Lam, Paul K.S. [Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong (China); Nugegoda, Dayanthi [Department of Biotechnology and Environmental Biology, RMIT University, Melbourne, Victoria (Australia)

    2005-07-01

    Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were comparatively studied over an acute 3-day exposure. In general, a post-bloom N. spumigena lysis caused opposite physiological responses to bloom densities of N. spumigena. Specifically, increases in glutathione (GSH) and glutathione peroxidase (GPx) and decreases in glutathione S-transferase (GST) were observed from the N. spumigena lysis. In contrast, N. spumigena cell densities decreased GSH and increased GST and lipid peroxidation (LPO) in mussels. Findings also suggest that at different stages of a toxic bloom, exposure may result in toxic stress to specific organs in the mussel.

  8. Experimental Substantiation of the Possibility of Developing Selenium- and Iodine-Containing Pharmaceuticals Based on Blue-Green Algae Spirulina Platensis

    CERN Document Server

    Mosulishvili, L M; Belokobylsky, A I; Khisanishvili, L A; Frontasyeva, M V; Pavlov, C C; Gundorina, S F

    2001-01-01

    The great potential of using blue-green algae Spirulina platensis as a matrix for the production of selenium- and iodine-containing pharmaceuticals is shown experimentally. The background levels of 31 major, minor and trace elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni (using -reaction), As, Br, Zn, Rb, Mo, Ag, Sb, I, Ba, Sm, Tb, Tm, Hf, Ta, W, Au, Hg, Th) in Spirulina platensis biomass were determined by means of epithermal neutron activation analysis. The dependence of selenium and iodine accumulation in spirulina biomass on a nutrient medium loding of the above elements was characterised. To demonstrate the possibilities of determining toxic element intake by spirulina biomass, mercury was selected. The technological parameters for production of iodinated treatment-and-prophylactic pills are developed.

  9. Survival and reproduction of some blue-green and green algae as affected by sewage water, fertilizer factory effluent, brassica oil, phenol, toluene and benzene.

    Science.gov (United States)

    Agrawal, S C; Gupta, S

    2009-01-01

    Fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene (showing the relative toxicity of different chemicals to different algae, and the antialgal nature of brassica oil). Dilution decreased the toxicity of these agents very little, indicating that they all were very toxic to algae. None of the agent induced the formation of any reproductive or dormant cells. Sewage water, fertilizer factory effluent, brassica oil and/or benzene favored the formation of necridia cells in Phormidium bohneri, P. foveolarum, Microcoleus chthonoplastes, Lyngbya birgei, and L. major filaments. Scenedesmus quadricauda shed off all spines earlier, Hormidium flaccidum fragmented less or not at all, Scytonema millei formed no false branch and heterocyst, Aphanothece pallida and Gloeocapsa atrata cells did not divide, Cosmarium granatum cells did not form any zygospore and Oedogonium sp. not any oogonia-like cells under all or most of treatments with 25-100 % sewage water, 1-100 % fertilizer factory effluent, 1-100 % brassica oil, 25-100 % phenol, toluene and benzene.

  10. Evaluation of disinfection by-product formation potential (DBPFP) during chlorination of two algae species--Blue-green Microcystis aeruginosa and diatom Cyclotella meneghiniana.

    Science.gov (United States)

    Liao, Xiaobin; Liu, Jinjin; Yang, Mingli; Ma, Hongfang; Yuan, Baoling; Huang, Ching-Hua

    2015-11-01

    Microcystis aeruginosa (blue-green alga) commonly blooms in summer and Cyclotella meneghiniana (diatom) outbreaks in fall in the reservoirs that serve as drinking water sources in Southeast China. Herein, an evaluation of disinfection by-product formation potential (DBPFP) from them during chlorination should be conducted. Five DBPs including trichloromethane (TCM), trichloronitromethane (TCNM), dichloroacetonitrile (DCAN), 1,1-dichloropropanone (1,1-DCP) and 1,1,1-trichloropropanone (1,1,1-TCP) were monitored. The formation potential of TCM and TCNM was enhanced with the increase of reaction time and chlorine dosage, whereas that of DCAN, 1,1-DCP and 1,1,1-TCP increased first and then fell with continuing reaction time. M. aeruginosa showed higher DBPFP than C. meneghiniana, the yield of DBPs varied with components of algal cells. The DBPFP order from components of M. aeruginosa was cell suspension (CS) ≈ intracellular organic matter (IOM) > extracellular organic matter (EOM) > cell debris (CD), which indicated that IOM was the main DBP precursors for M. aeruginosa. The yields of DBPs from components of C. meneghiniana were in the order of CS>IOM≈ CD ≈ EOM, suggesting that three components made similar contributions to the total DBP formation. The amount of IOM with higher DBPFP leaked from both algae species increased with the chlorine dosage, indicating that chlorine dosage should be considered carefully in the treatment of eutrophic water for less destroying of the cell integrity. Though fluorescence substances contained in both algae species varied significantly, the soluble microbial products (SMPs) and aromatic protein-like substances were the main cellular components that contributed to DBP formation for both algae.

  11. Replacement value of blue-green alga (Spirulina platensis) for fishmeal and a vitamin-mineral premix for broiler chicks.

    Science.gov (United States)

    Venkataraman, L V; Somasekaran, T; Becker, E W

    1994-07-01

    1. The effect of sun-dried Spirulina platensis in poultry diets was studied in a 12-week feeding trial by replacing either fishmeal (FM) or groundnut cake (GC) in a commercial diet with algae at isonitrogenous concentrations of 140 g/kg and 170 g/kg respectively. Additional vitamins/minerals were omitted from the algal diets because Spirulina is rich in them. 2. Efficiency of food utilisation, protein efficiency ratio and dressing percentage indicated that substitution of FM or GC by alga did not affect the performance of broilers. 3. None of the diets affected the weights, compositions and histopathology of the various organs of the chicks. 4. Meat quality remained unchanged except for a more intense colour in the case of birds fed on the alga-containing diets.

  12. Low energy method of manufacturing high-grade protein using blue-green algae of the genus Spirulina

    Energy Technology Data Exchange (ETDEWEB)

    Leesley, M.E.; Newsom, T.M.; Burleson, J.D.

    1981-01-01

    Algae are well suited to replace many conventional sources of protein because of their efficient use of energy, land, and raw materials. The most promising genus, Spirulina, is compared with conventional protein sources on the bases of energy efficiency, land usage, and production costs.

  13. Preliminary laboratory experimentation on the potential of mass-scale cultivation of a high-potein blue-green alga, spirulina geitleri, utilizing cattle feedlot manure

    Energy Technology Data Exchange (ETDEWEB)

    Santerre, M.T.; Dugan, G.L.; Takahashi, P.K.

    1978-01-01

    Major detriments to beef production in Hawaii are the cost of feed and the problems associated with the treatment and disposal of the manure in a environmentally safe manner. In an effort to alleviate these problems, laboratory studies were conducted on the feasibility of culturing the high protein (> 50%) blue-green alga Spirulina in elutriated (washed) manure and in the supernatant resulting from anaerobically digesting animal manure. This scheme lends itself to a proposed environmentally acceptable integrated manure handling system with the major outputs being a high-protein feed ingredient (Spirulina); methane gas for heating and power production; and a stabilized sludge (from the anaerobic digester), that can be used as a soil conditioner. The laboratory results proved that unialgal cultures of Spirulina geitleri were capable of attaining dense concentrations in medium prepared from elutriated manure or the supernatant from anaerobically digested cattle manure; however, a high concentration (> 1.0 g/l) of sodium bicarbonate was necessary for successful establishment of growing cultures. In addition, supplemental nitrogen was required to maximize the utilization of the dissolved nutrients in the digester supernatant. Several potential sources of waste carbon dioxide and nitrogen are available for integration into the scheme. Finally, Spirulina geitleri responded favorably to the substitution of manure-enriched modified FCRG medium with a 20% seawater mixture, thus opening up the possibility of utilizing this organism in future OTEC-aquacultural projects. 3 figures, 6 tables.

  14. In vitro and in vivo safety assessment of edible blue-green algae, Nostoc commune var. sphaeroides Kützing and Spirulina plantensis

    Science.gov (United States)

    Yang, Yue; Park, Youngki; Cassada, David A.; Snow, Daniel D.; Rogers, Douglas G.; Lee, Jiyoung

    2011-01-01

    Blue-green algae (BGA) have been consumed as food and herbal medicine for centuries. However, safety for their consumption has not been well investigated. This study was undertaken to evaluate in vitro and in vivo toxicity of cultivated Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP). Neither NO nor SP contained detectable levels of microcystin (MC)-LA, MC-RR, MC-LW and MC-LR by LC/MS/MS. Cell viability remained ~70-80% when HepG2 cells were incubated with 0-500 μg/ml of hexane, chloroform, methanol and water-extractable fractions of NO and SP. Four-week-old male and female C57BL/6J mice were fed an AIN-93G/M diet supplemented with 0, 2.5% or 5% of NO and SP (wt/wt) for 6 months. For both genders, BGA-rich diets did not induce noticeable abnormality in weight gain and plasma alanine aminotransferase (ALT) and aspartate aminotransferase concentrations except a significant increase in plasma ALT levels by 2.5% NO supplementation in male mice at 6 month. Histopathological analysis of livers, however, indicated that BGA did not cause significant liver damage compared with controls. In conclusion, our results suggest that NO and SP are free of MC and the long-term dietary supplementation of up to 5% of the BGA may be consumed without evident toxic side-effects. PMID:21473896

  15. Lipid extract of Nostoc commune var. sphaeroides Kutzing, a blue-green alga, inhibits the activation of sterol regulatory element binding proteins in HepG2 cells.

    Science.gov (United States)

    Rasmussen, Heather E; Blobaum, Kara R; Park, Young-Ki; Ehlers, Sarah J; Lu, Fan; Lee, Ji-Young

    2008-03-01

    Nostoc commune var. sphaeroides Kützing (N. commune), a blue-green alga, has been used as both a food ingredient and in medicine for centuries. To determine the effect of N. commune on cholesterol metabolism, N. commune lipid extract was incubated at increasing concentrations (25-100 mg/L) with HepG2 cells, a human hepatoma cell line. The addition of N. commune lipid extract markedly reduced mRNA abundance of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and LDL receptor (LDLR) (P commune lipid extract confirmed the inhibitory role of N. commune in cholesterol synthesis (P commune lipid extract, expression of sterol regulatory element binding protein 2 (SREBP-2) was assessed. Whereas mRNA for SREBP-2 remained unchanged, SREBP-2 mature protein was reduced by N. commune (P commune lipid extract also decreased SREBP-1 mature protein by approximately 30% (P commune lipid extract inhibits the maturation process of both SREBP-1 and -2, resulting in a decrease in expression of genes involved in cholesterol and fatty acid metabolism.

  16. Effects of spirulina, a blue-green alga, on bone metabolism in ovariectomized rats and hindlimb-unloaded mice.

    Science.gov (United States)

    Ishimi, Yoshiko; Sugiyama, Fumie; Ezaki, Junko; Fujioka, Maiko; Wu, Jian

    2006-02-01

    The safety and effectiveness were examined of the spirulina alga on bone metabolism in ovariectomized estrogen-deficient rats and hindlimb-unloaded mice. The dosage range was from an amount equal to that recommended in so-called health foods for humans (0.08 g/kg BW/day) to a 100-fold higher dose. The bone mineral density (BMD) of the whole femur and tibia of ovariectomized rats in the any spirulina-treated groups was not significantly different from that of the ovariectomized group, although BMD of the distal femur and proximal tibia was significantly lower in the spirulina-treated groups than in the ovariectomized group after a 6 week-experimental period. BMD of the femur and tibia was not affected by treatment with any dose of spirulina in hindlimb-unloaded mice. These results suggest that the intake of spirulina decreased BMD in the trabecular bone of rodents under estrogen-deficient conditions.

  17. Flash kinetics and light intensity dependence of oxygen evolution in the blue-green alga Anacystis nidulans.

    Science.gov (United States)

    Ley, A C; Babcock, G T; Sauer, K

    1975-05-15

    Patterns of oxygen evolution in flashing light for the glue-green alga Anacystis nidulans are compared with those for broken spinach chloroplasts and whole cells of the green alga Chlorella pyrenoidosa. The oscillations of oxygen yield with flash number that occur in both Anacystis and Chlorella, display a greater degree of damping than do those of isolated spinach chloroplasts. The increase in damping results from a two- to threefold increase in the fraction (alpha) of reaction centers "missed" by a flash. The increase in alpha cannot be explained by non-saturing flash intensities or by the dark reduction of the oxidized intermediates formed by the flash. Anaerobic conditions markedly increase alpha in Anacystis and Chlorella but have no effect on alpha in broken spinach chloroplasts. The results signify that the mechanism of charge separation and water oxidation involved in all three orgainsms is the same, but that the pool of secondary electron acceptors between Photosystem II and Photosystem I is more reduced in the dark, in the algal cells, than in the isolated spinach chloroplasts. Oxygen evolution in flashing light for Anacystis and Chlorella show light saturation curves for the oxygen yield of the third flash (Y3) that differ markedly from those of the steady-state flashes(YS). In experiments in which all flashes are uniformly attenuated, Y3 requires nearly twice as much light as YS to reach half-saturation. Under these conditions Y3 has a sigmoidal dependence on intensity, while that of YS is hyperbolic. These differences depend on the number of flashes attenuated. When any one of the first three flashes is attenuated, the variation of Y3 with intensity resembles that of YS. When two of the first three flashes are attenuated, Y3 is intermediate in shape between the two extremes. A quantitative interpretation of these results based on the model of Kok et al. (Kik, B., Forbush, B.and McGloin, M. (1970) Photochem. Photobiol. 14, 307-321) fits the experimental

  18. Multistage continuous cultivation of blue-green alga Spirulina maxima in the flat tank photobioreactors with recycle

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; Leduy, A.

    1985-02-01

    Spirulina maxima was continuously cultivated in four 64-liter flat tank photobioreactors in cascade, under continuous 30 Klx fluorescent light and nonaseptic condition, in an industrial grade synthetic medium which bubbled with atmospheric air. The increase in the number of stages resulted in the higher biomass concentration and allowed operation with a dilution rate D higher than the alga specific growth rate. However, multistage operation does not permit a significant increase in productivity. The recycling of the all culture medium with biomass increased the net productivity of the first two stages of the multistage system. The flat tank design offered great advantages over other geometrical configurations by occupying less space for indoor cultivation, minimizing the water loss by evaporation, and permitting a greater flexibility in construction, installation, and operation. This system was operating continuously for two years in our laboratory for indoor mass production of S. maxima biomass. The flat tank configuration gave the highest areal productivity Pa = 60.5 g/squared m.d and highest volumetric productivity Pv = 1.17 g/L.d when operated as a single stage continuous cultivation with high solid recycle. These values are the highest ever reported for any indoor or outdoor mass production system for S. maxima. 26 references.

  19. Blood pressure and hepatocellular effects of the cyclic heptapeptide toxin produced by the freshwater cyanobacterium (blue-green alga) Microcystis aeruginosa strain PCC-7820.

    Science.gov (United States)

    Theiss, W C; Carmichael, W W; Wyman, J; Bruner, R

    1988-01-01

    Laboratory rats and mice were used to investigate the hepatotoxicity caused by the cyclic heptapeptide (mol. wt 994) termed microcystin-LR. Microcystin-LR (also known as cyanoginosin-LR) is produced by the freshwater cyanobacterium (blue-green alga) M. aeruginosa strain PCC-7820. In time course histopathology studies with mice significant liver damage, with an absence of pulmonary emboli, were observed after 15 min. Pulmonary emboli did not appear until 1 hr. In rats, significant liver damage and the presence of occasional emboli were observed at 20 min. Pulmonary emboli did not contain fibrin nor appear life-threatening in any case and resembled the globular eosinophilic debris found in the liver sinusoids and central veins. Measurements of rat femoral arterial, jugular venous and hepatic portal venous blood pressures during the course of toxicity revealed a slowly declining arterial pressure and stable, normal venous pressures. Blood lactic acid levels rose in parallel with the fall in arterial pressure, a pattern typical of hemorrhagic shock. There was no indication of venous congestion that would accompany right heart failure. Isolated, perfused rat livers dosed with toxin showed rapid changes in the liver, including cessation of bile flow within 10 min and complete obliteration of normal lobular architecture within 60 min. No effect of the toxin was observed in isolated perfused rat heart. We conclude that in the mouse and rat, microcystin-LR is a potent, rapid-acting, direct hepatotoxin, with the immediate cause of death in acute toxicities being hemorrhagic shock secondary to massive hepatocellular necrosis and collapse of hepatic parenchyma.

  20. Hypolipidemic Effect of a Blue-Green Alga (Nostoc commune) Is Attributed to Its Nonlipid Fraction by Decreasing Intestinal Cholesterol Absorption in C57BL/6J Mice.

    Science.gov (United States)

    Ku, Chai Siah; Kim, Bohkyung; Pham, Tho X; Yang, Yue; Weller, Curtis L; Carr, Timothy P; Park, Young-Ki; Lee, Ji-Young

    2015-11-01

    We previously demonstrated that Nostoc commune var. sphaeroids Kützing (NO), a blue-green alga (BGA), exerts a hypolipidemic effect in vivo and its lipid extract regulates the expression of genes involved in cholesterol and lipid metabolism in vitro. The objective of this study was to investigate whether the hypolipidemic effect of NO is attributed to an algal lipid or a delipidated fraction in vivo compared with Spirulina platensis (SP). Male C57BL/6J mice were fed an AIN-93M diet containing 2.5% or 5% of BGA (w/w) or a lipid extract equivalent to 5% of BGA for 4 weeks to measure plasma and liver lipids, hepatic gene expression, intestinal cholesterol absorption, and fecal sterol excretion. Plasma total cholesterol (TC) was significantly lower in 2.5% and 5% NO-fed groups, while plasma triglyceride (TG) levels were decreased in the 5% NO group compared with controls. However, neither NO organic extract (NOE) nor SP-fed groups altered plasma lipids. Hepatic mRNA levels of sterol regulatory element-binding protein 2, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), carnitine palmitoyltransferase-1α, and acyl-CoA oxidase 1 were induced in 5% NO-fed mice, while there were no significant changes in hepatic lipogenic gene expression between groups. NO, but not NOE and SP groups, significantly decreased intestinal cholesterol absorption. When HepG2 cells and primary mouse hepatocytes were incubated with NOE and SP organic extract (SPE), there were marked decreases in protein levels of HMGR, low-density lipoprotein receptor, and fatty acid synthase. In conclusion, the nonlipid fraction of NO exerts TC and TG-lowering effects primarily by inhibiting intestinal cholesterol absorption and by increasing hepatic fatty acid oxidation, respectively.

  1. Inhibition of tumor invasion and metastasis by calcium spirulan (Ca-SP), a novel sulfated polysaccharide derived from a blue-green alga, Spirulina platensis.

    Science.gov (United States)

    Mishima, T; Murata, J; Toyoshima, M; Fujii, H; Nakajima, M; Hayashi, T; Kato, T; Saiki, I

    1998-08-01

    We have investigated the effect of calcium spirulan (Ca-SP) isolated from a blue-green alga, Spirulina platensis, which is a sulfated polysaccharide chelating calcium and mainly composed of rhamnose, on invasion of B16-BL6 melanoma, Colon 26 M3.1 carcinoma and HT-1080 fibrosarcoma cells through reconstituted basement membrane (Matrigel). Ca-SP significantly inhibited the invasion of these tumor cells through Matrigel/fibronectin-coated filters. Ca-SP also inhibited the haptotactic migration of tumor cells to laminin, but it had no effect on that to fibronectin. Ca-SP prevented the adhesion of B16-BL6 cells to Matrigel and laminin substrates but did not affect the adhesion to fibronectin. The pretreatment of tumor cells with Ca-SP inhibited the adhesion to laminin, while the pretreatment of laminin substrates did not. Ca-SP had no effect on the production and activation of type IV collagenase in gelatin zymography. In contrast, Ca-SP significantly inhibited degradation of heparan sulfate by purified heparanase. The experimental lung metastasis was significantly reduced by co-injection of B16-BL6 cells with Ca-SP. Seven intermittent i.v. injections of 100 microg of Ca-SP caused a marked decrease of lung tumor colonization of B16-BL6 cells in a spontaneous lung metastasis model. These results suggest that Ca-SP, a novel sulfated polysaccharide, could reduce the lung metastasis of B16-BL6 melanoma cells, by inhibiting the tumor invasion of basement membrane probably through the prevention of the adhesion and migration of tumor cells to laminin substrate and of the heparanase activity.

  2. Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants.

    Science.gov (United States)

    Tripathi, R D; Dwivedi, S; Shukla, M K; Mishra, S; Srivastava, S; Singh, R; Rai, U N; Gupta, D K

    2008-02-01

    Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.

  3. Langmuir-Blodgett Film of Phycobilisomes from Blue-Green Alga Spirulina platensis%钝顶螺旋藻(Spirulina platensis)藻胆体Langmuir-Blodgett膜

    Institute of Scientific and Technical Information of China (English)

    陈超; 张玉忠; 陈秀兰; 周百成; 高鸿钧

    2003-01-01

    The phycobilisomes were isolated from blue-green alga Spirulina platensis, and could form monolayer film at air/water interface. The monolayer film of phycobilisomes was transferred to newly cleaved mica, and coated with gold. Scanning tunneling microscope was used to investigate the structure of the Langmuir-Blodgett film of phycobilisomes. It was shown that phycobilisomes in the monolayer arrayed in rows with core attaching on the substrate surface and rods radiating towards the air phase, this phenomenon was similar to the arrangement of phycobilisomes on cytoplasmic surface of thylakoid membrane in vivo. The possible applications of the Langmuir-Blodgett film of phycobilisomes were also discussed.%从钝顶螺旋藻中分离制备完整藻胆体, 然后滴加于空气/水界面上, 应用LB膜技术制备藻胆体LB膜. 结果表明, 藻胆体在空气/水界面上具有很好的成膜性能. 将藻胆体LB单层膜转移到刚揭开的云母表面, 喷一层金, 然后用扫描隧道显微镜观察. 结果表明, 藻胆体在Langmuir-Blodgett膜中的排列方式与其在体内类囊体膜表面的排列方式类似, 一排排聚集在一起, 然后排列成膜. 藻胆体的"核"吸附在云母表面, 而藻胆体的"杆"伸向外面. 由于钝顶螺旋藻易于规模化培养, 藻胆体容易批量制备, 加之藻胆体具有的独特的光物理、光化学特性和良好的成膜性能, 以及本身就是纳米量级的颗粒(50~70 nm), 预示着藻胆体在纳米光电子器件中具有很好的应用前景.

  4. Visualization of channels connecting cells in filamentous nitrogen-fixing cyanobacteria.

    Science.gov (United States)

    Omairi-Nasser, Amin; Haselkorn, Robert; Austin, Jotham

    2014-07-01

    Cyanobacteria, formerly called blue-green algae, are abundant bacteria that carry out green plant photosynthesis, fixing CO2 and generating O2. Many species can also fix N2 when reduced nitrogen sources are scarce. Many studies imply the existence of intracellular communicating channels in filamentous cyanobacteria, in particular, the nitrogen-fixing species. In a species such as Anabaena, growth in nitrogen-depleted medium, in which ∼10% of the cells differentiate into anaerobic factories for nitrogen fixation (heterocysts), requires the transport of amino acids from heterocysts to vegetative cells, and reciprocally, the transport of sugar from vegetative cells to heterocysts. Convincing physical evidence for such channels has been slim. Using improved preservation of structure by high-pressure rapid freezing of samples for electron microscopy, coupled with high-resolution 3D tomography, it has been possible to visualize and measure the dimensions of channels that breach the peptidoglycan between vegetative cells and between heterocysts and vegetative cells. The channels appear to be straight tubes, 21 nm long and 14 nm in diameter for the latter and 12 nm long and 12 nm in diameter for the former.-Omairi-Nasser, A., Haselkorn, R., Austin, J. II. Visualization of channels connecting cells in filamentous nitrogen-fixing cyanobacteria. © FASEB.

  5. 水体无机碳升高对蓝绿藻生长和种群竞争的影响研究进展%A Review on the Effect of Inorganic Carbon on Blue-green Algae Growth

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The blue-green algae is one kind of the important components of phytoplankton in waterbodies. It is also the main primary producer of freshwater and marine ecosystems. In recent years, with the increase of CO2emission to atmosphere, the global climate is changing significantly. The frequent extreme weather events exert great impact on the concentration of dissolved organic carbon in waterbodies, as a consequence, CO2-concentrating mechanism (CCM) of algae is affected. Through CCM, the concentration of CO2 could be increased located at RubisCO of the algae cells, in order to promote the photosynthesis and diminish light respiration of algae. Based on the climate change due to the increase of CO2 concentration, the equilibrium among inorganic carbon in different forms in open waterbodies was first described in this review. The carbon recycling processes in waterbodies and their effect on the algae was then analyzed. Various experimental simulation technology of the elevated inorganic carbon concentration in the environment as well as the research method of the algae growth and species competition with the elevated CO2 concentration were also summarized.According to the researches on the CCM of blue-green algae, inoraganic carbon enter the blue-green algae via the Calvin Cycle. Under the catalysis of carbonic anhydrase, HCO3- and CO32-as the form of inorganic carbon could be transformed into CO2, which increases the CO2 concentration around RubisCO and the inorganic carbon utilization efficiency of algae. However, CCM of algae is also affected by pH, illumination, nitrogen and phosphorus, etc. Based on this theory, the effect of inorganic carbon on the cell structure, size and the individual cell proliferation of blue-green algae was summarized.Some researchers indicated that CO2 with high concentration could promote the growth of nuclear protein of algae cells, and this phenomenon is much significant for the algae cells with small size. Since the CO2 could be

  6. 应用不同材料过滤去除海河蓝藻水华研究%Study on Removal of Blue-green Algae from Haihe River by Several Filter Materials

    Institute of Scientific and Technical Information of China (English)

    周绪申; 李慧峰; 罗阳; 林超; 张左立; 赵立虹

    2012-01-01

    Algae bloom broke out in Haihe River in July 2012. Algal community was analyzed during that time and several common materials were experimented on algae removal by direct filtration apparatus. The results showed that 42 species belonging to 5 phyta of phytoplankton were identified. Algae cell density was up to 1.89×108 / L and Microcysis aeruginosa belonging to Cyanophyta was dominant species. The algae removal efficiency (cell density and chlorophyll a) of cotton, rapid filter paper and acrylic was over 80%. The blue-green algae removal efficiency of five kinds of materials was over 80%, in which cotton was the best filter (96.02%). Most of the blue-green algae with group or larger volume were easier to be filtered by the materials. The rate of filtering algae from fast to slow is as follows: sponge > plant stalk fiber> nylon scrubbing cloth> gauze > AcryliO # 25 plankton net> copper mesh> cotton> non-woven fabric > Quick filter paper.%于2012年7月海河蓝藻爆发期间,对水体藻类群落组成进行了分析,对生活中常见材料过滤除藻能力进行了研究.结果表明海河蓝藻爆发期间共发现藻类5门42种,藻类细胞密度达1.89×108个/L,其中蓝藻门的铜绿微囊藻为本次藻类爆发的优势种类.所选过滤材料处理藻细胞密度和叶绿素a效率超过80%的有3种,分别为:脱脂棉、快速滤纸和腈纶.蓝藻去除效率超过80%的材料有5种,其中脱脂棉的处理效果最佳,处理效率达96.02%,群体和体积较大蓝藻大部分能被过滤去除.过滤材料过滤藻类速率由快至慢依次为:海绵4层>植物秸秆纤维>尼龙擦洗布>纱布16层>腈纶>25号浮游生物网>细铜丝网>脱脂棉>无纺布4层>快速滤纸.

  7. Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation. [economic analysis of ammonia production

    Science.gov (United States)

    Stokes, B. O.; Wallace, C. J.

    1978-01-01

    Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment.

  8. Start-up strategy of contingency plan against blue-green algae crisis based on online method%基于在线方法的蓝藻危机应急预案启动策略

    Institute of Scientific and Technical Information of China (English)

    余昇; 徐寅峰; 董玉成; 郑斐峰

    2011-01-01

    It is a key problem to decide the time at which to active a contingency plan in the area of emergency management. Blue-green algae crisis represents a kind of emergency management problem whose growth rate or diffusion speed is unexpected. Based on online method and taking this crisis as the background, this work presented contingency plan start-up strategies for two cases where the loss is ceased immediately and where the loss gradually decreases to zero respectively. These strategies were proved to be optimal. An illustration about blue-green algae crisis in Taihu Lake was given as well. The conclusions provide guidance for deci8ion makers to solve crucial emergencies.%应对危机时,何时启动预案是应急管理中需要解决的关键问题.太湖蓝藻危机代表一类生长速度或传播速度不确定的突发事件,以此为背景基于在线方法,考虑了预案启动后损失立即停止和损失逐渐减少至零两种情形,针对这两种情形,分别设计了应急预案启动策略,并证明它们是最优启动策略,最后对太湖蓝藻危机进行实例计算并分析了策略的竞争性能,研究结果具有一定的实际指导意义和参考价值.

  9. Prediction of Blue-Green Algae Bloom Using Stepwise Multiple Regression Between Algae & Related Environmental Factors in Hongze lake%洪泽湖藻类与环境因子逐步回归统计和蓝藻水华初步预测

    Institute of Scientific and Technical Information of China (English)

    王兆群; 张宁红; 张咏

    2012-01-01

    This study deals with the ralation between algal biomass and 12 environmental factors such as weter temperature (WT) .suspend solids(SS) ,DO,COD,etc.based on the mongitoring data from 2008?010 in Hongze lake, the stepwise multiple regression statistical method was used to calculate the relation between algalchlorophyll-a( Chla) , total algal density. Blue-green algae density, etc,and these environmental factors. The results showed that D.TP.TN and NH,-\\ were the. most significant related factors to algae density, WT,SD,D were the most significant, related factors to blue-green algae density. These can be used to predict the Blue-green algae bloom in the Hongze lake.%以洪泽湖2008-2010年的连续监测资料为基础,运用多元逐步回归统计方法,选择术温等12项环境因子与藻类叶绿素a等5项生物因子进行进步回归分析,找出与生物因子显著相关的因子,建立多元逐步回归方程,预测洪泽湖藻类密度的变化情况,初步进行了洪泽湖蓝藻水华的预测预报.结果显示,总磷、总氮、氨氮和水深为洪泽湖藻类密度的显著相关因子,透明度、水温、水深为蓝藻密度的显著相关因子.

  10. Amino acid compositon and microbial contamination of spirulina maxima, a blue-green alga, grown on the effluent of different fermented animal wastes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.F.; Pond, W.G.

    1981-01-01

    The nutrient compositions of various fermented manures were compared. Large differences in the mineral concentration were observed. There were no important differences among the amino acid composition of S. spirulina grown on the different nutrient media. All were low in methionine, but were rich in glutamic acid, aspartic acid, arginine, and leucine. The crude protein content was 71.8-60.1%. Considerable contamination of the waste-grown algae with yeast, fungi, and sporogenous bacteria was experienced.

  11. Repression of proinflammatory gene expression by lipid extract of Nostoc commune var sphaeroides Kützing, a blue-green alga, via inhibition of nuclear factor-kappaB in RAW 264.7 macrophages.

    Science.gov (United States)

    Park, Young-Ki; Rasmussen, Heather E; Ehlers, Sarah J; Blobaum, Kara R; Lu, Fan; Schlegal, Vicki L; Carr, Timothy P; Lee, Ji-Young

    2008-02-01

    We investigated whether lipid extract from a blue-green alga, N commune, modulates proinflammatory gene expression in RAW 264.7 macrophages. The cells were incubated with N commune lipid extract (0-100 microg/mL) and subsequently activated by LPS (100 ng/mL). Quantitative real-time PCR analysis showed that mRNA abundance of proinflammatory mediators, including TNF-alpha, COX-2, IL-1beta, IL-6, and iNOS, was significantly reduced by N commune lipid extract in a dose-dependent manner. Secretion of TNF-alpha and IL-1beta into cell culture medium was also significantly decreased by N commune lipid extract. Thin-layer chromatography-densitometry analysis showed that N commune lipid extract contained approximately 15% of fatty acids. To determine whether the inhibition of proinflammatory mediator production by N commune lipid extract is primarily conferred by fatty acids in the lipid extract, macrophages were incubated with 100 microg/mL of N commune lipid extract or 15 microg/mL of a fatty acid mixture, which was formulated to reflect the fatty acid composition of N commune lipid extract. The fatty acid mixture significantly reduced RNA abundance of TNF-alpha and COX-2, but to a lesser extent than did the N commune lipid extract, suggesting the presence of additional bioactive compounds with an antiinflammatory property in the lipid extract. As NF-kappaB is a major regulator for the proinflammatory gene expression, we measured its DNA-binding activity. DNA-binding activity of NF-kappaB was significantly reduced by N commune lipid extract. In conclusion, our study suggests that N commune lipid extract represses the expression of proinflammatory genes in RAW 264.7 macrophages, at least in part, by inhibiting the activation of NF-kappaB pathway.

  12. Utilization of nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Brewbaker, J.L.; Beldt, R. van den; MacDicken, K.; Budowski, G.; Kass, D.C.L.; Russo, R.O.; Escalante, G.; Herrera, R.; Aranguren, J.; Arkcoll, D.B.; Doebereinger, J. (cord.)

    1983-01-01

    Six papers from the symposium are noted. Brewbaker, J.L., Beldt, R. van den, MacDicken, K. Fuelwood uses and properties of nitrogen-fixing trees, pp 193-204, (Refs. 15). Includes a list of 35 nitrogen-fixing trees of high fuelwood value. Budowski, G.; Kass, D.C.L.; Russo, R.O. Leguminous trees for shade, pp 205-222, (Refs. 68). Escalante, G., Herrera, R., Aranguren, J.; Nitrogen fixation in shade trees (Erythrina poeppigiana) in cocoa plantations in northern Venezuela, pp 223-230, (Refs. 13). Arkcoll, D.B.; Some leguminous trees providing useful fruits in the North of Brazil, pp 235-239, (Refs. 13). This paper deals with Parkia platycephala, Pentaclethra macroloba, Swartzia sp., Cassia leiandra, Hymenaea courbaril, dipteryz odorata, Inga edulis, I. macrophylla, and I. cinnamonea. Baggio, A.J.; Possibilities of the use of Gliricidia sepium in agroforestry systems in Brazil, pp 241-243; (Refs. 15). Seiffert, N.F.; Biological nitrogen and protein production of Leucaena cultivars grown to supplement the nutrition of ruminants, pp 245-249, (Refs. 14). Leucaena leucocephala cv. Peru, L. campina grande (L. leucocephala), and L. cunningham (L. leucocephalae) were promising for use as browse by beef cattle in central Brazil.

  13. South Tai Lake' s Main Lake Inlet Blue-green Alga Water Bloom Space and Time Distribution Rule and Related Response Factor Analysis%南太湖入湖口蓝藻水华时空分布规律及相关响应因子分析

    Institute of Scientific and Technical Information of China (English)

    杨晓红; 陈江; 周李; 常艳春; 吴建; 许盈斐

    2011-01-01

    利用2008年和2009年南太湖蓝藻监测数据,分析研究主要入湖口的蓝藻水华时空分布规律,寻找与蓝藻生长密切相关的响应因子并将其作为蓝藻预警指示指标,为环保部门制定蓝藻应急监测预案、提高蓝藻预警预测的准确性提供科学参考.%Based on the monitoring data of blue-green algae in South Tai Lake in 2008 and 2009, Spatial and temporal distribution of bule-green algae blooms at the main lake inlets were studied, and the response factors closely related to bule-green algae growth were discussed. Bule-green algae warning index were established, and it can be used to provide scientific reference to the formulation of algous contingent monitoring plan and the accuracy enhancement of algous precaution mechanism for the Environment Protection Department.

  14. 青霉素处理检查和分离蓝藻细胞液泡%Determination and Isolation of Cell Vacuoles from Blue-green Algae by Penicillin Method

    Institute of Scientific and Technical Information of China (English)

    郭碧薇; 易平; 刘希玲; 郭厚良

    2003-01-01

    Growing in the liquid medium containing penicillin, the cells of the Cyanobacteria,Anabaena 7120, Nostoc flagelliforme, and Synechocystis 6803 were broken and vacuoles were released. Percentage of broken cells declined and percentage of broken cells increased with the growing days of the algae. The percentage of vacuoles to broken cells were respectively 0.7%, 0.8%, and 13.3% in the three types of algae Anabaena 7120, N.flagelliforme and Synechocystis 6803 which had grown for 3 days.

  15. Biochemical changes induced by fungicides in nitrogen fixing Nostoc sp.

    Science.gov (United States)

    Deviram, G V N S; Pant, Gaurav; Prasuna, R Gyana

    2013-01-01

    The present study indicates the effect of fungicides (approved by WHO) and their behavior on nitrogen fixer of rice eco system Nostoc sp. Application of plant protecting chemicals at recommended levels braced up the growth of blue green algae thereby enhancing heterocyst formation and nitrogenase activity. Nostoc sp demoed varying degrees of sensitivity to fungicides. Biomass yield, protein, carbohydrate content reduced after 3pg/mL concentration. Heterocyst damage was observed from 4μg/mL, Proline content increased with increase in fungicide concentration, utmost yellowing of the culture started from 4μg/mL. The decreasing order of the toxicity to Nostoc sp with fungicides was Mancozeb> Ediphenphos> Carbendazim> Hexaconazole.

  16. Blue green component and integrated urban design

    Directory of Open Access Journals (Sweden)

    Stanković Srđan M.

    2016-01-01

    Full Text Available This paper aims to demonstrate the hidden potential of blue green components, in a synergetic network, not as separate systems, like used in past. The innovative methodology of the project Blue Green Dream is presented through examples of good practice. A new approach in the project initiate thoughtful planning and remodeling of the settlement for the modern man. Professional and scientific public is looking for way to create more healthy and stimulating place for living. However, offered integrative solutions still remain out of urban and architectural practice. Tested technologies in current projects confirmed measurability of innovative approaches and lessons learned. Scientific and professional contributions are summarized in master's and doctoral theses that have been completed or are in process of writing.

  17. Blue-Green Solutions in Urban Development

    Science.gov (United States)

    Karlsson, Caroline; Kalantari, Zahra

    2017-04-01

    With the ongoing urbanisation and increasing pressure for new housing and infrastructure, the nexus of developing compact, energy-efficient and yet liveable and sustainable cities is urgent to address. In this context, blue-green spaces and related ecosystem services (ES) are critical resources that need to be integrated in policy and planning of urban. Among the ES provided by blue-green spaces, regulating ES such as water retention and purification are particularly important in urban areas, affecting water supply and quality, related cultural ES and biodiversity, as well as cities potential to adapt to climate change. Blue-green infrastructure management is considered a sustainable way to reducing negative effects of urbanisation, such as decreasing flood risks, as well as adapting to climate change for example by controlling increasing flood and drought risks. Blue-green infrastructure management can for example create multifunctional surfaces with valuable environmental and social functions and generally handle greenways and ecological networks as important ecosystem service components, for example for stormwater regulation in a sustainable urban drainage system. The Norrström drainage basin (22,000 km2) is a large demonstrator for Blue-green infrastructure management. Both urbanisation and agriculture are extensive within this basin, which includes the Swedish capital Stockholm and is part of the fertile Swedish belt. Together, the relatively high population density combined with agricultural and industrial activities in this region imply large eutrophication and pollution pressures, not least transferred through storm runoff to both inland surface waters and the coastal waters of the Baltic Sea. The ecosystems of this basin provide highly valued but also threatened services. For example, Lake Mälaren is the single main freshwater supply for the Swedish capital Stockholm, as well as a key nutrient retention system that strongly mitigates waterborne nutrient

  18. Viability of dried vegetative cells or filaments, survivability and/or reproduction under water and light stress, and following heat and UV exposure in some blue-green and green algae.

    Science.gov (United States)

    Agrawal, S C; Pal, U

    2003-01-01

    Vegetative cells in dried, mucilagenous mass of Gloeocapsa aeruginosa and Aphanothece nidulans, reticulum of Hydrodictyon reticulatum, mucilagenous mass of Chroococcus minor, and filaments of Oedogonium sp. and Scytonema hofmanni died within 1/2, 1/2, 1/2, 1, 3 and 6 h, respectively, while dried vegetative filaments of Phormidium foveolarum retained under similar storage conditions viability for 4 d. P. foveolarum tolerated 1 mol/L NaCl. The resistance to desiccation in P. foveolarum exhibited similar dependence as that to heat or UV light. The water stress imposed on growing algae either on high-agar solid media or in NaCl-containing liquid media reduced at various levels or altogether inhibited the survival of vegetative parts in all, the cell division in C. minor, G. aeruginosa and A. nidulans, formation of heterocyst and false branch in S. hofmanni, oogonium in Oedogonium sp., and daughter net in H. reticulatum. Heat or UV shock of any level also produced similar effects as that by water stress. P. foveolarum tolerated low light level of 10 and 2 mumol m-2 s-1 and no light longer than the rest of other algae studied. Tolerance of microalgal forms to water, heat or UV stress depends primarily upon cell-wall characteristics or cell-sap osmotic properties rather than their habitats, morphology and prokaryotic or eukaryotic nature.

  19. The Blue-green Algae Calcification Test Preliminary Research on Land Facies Calcium Carbonate Deposit in Different Water Hydrodynamic Condition%不同水动力下陆相碳酸钙沉积的蓝藻钙化试验的初步研究

    Institute of Scientific and Technical Information of China (English)

    程星; 石方红; 李本刚; 张金梅; 潘响亮

    2012-01-01

    The surface calcification is a kind of deposit on the earth, which is an important deposit type of land calci- um carbonate. For a long time, the hydrodynamic formation cause of land calcium carbonate deposit is familiar to the researchers. The research of the biological cause of the formation is relatively fewer. In fact, the biological cause should be not ignored as well, especially algous deposit process. From imitating for field hydrodynamic force condi- tion, taking the blue-green algae for example, the research makes a biological deposit test under the different hydrody- namic force condition. From the test, we get optimum hydrodynamic condition of algae growth and their calcification rate, that is under the rate of 0 ~ 60 rpm, under the excessive strong , the growth of blue-green algae will be restrain- ed, and reduce the deposit rate of calcium carbonate. Under the condition of waterfall, hydrodynamic force is strong, in calcium carbonate depositing process, hydrodynamic formation cause of land calcium carbonate deposit is the lead cause; Under the weaker hydrodynamic condition, such as in fiver bed, biological calcification deposit will be the lead cause. Therefore, hydrodynamic-biological cause viewpoint has been proposed in the article. From the field algous samples, the calcium carbonate depositing test has been done under the different water hy- drodynamic conditions. The test results show that under the faster water condition, most calcium carbonate will deposit very quick, and fewer algae calcium carbonate will precipitate because of adverse living environment under the condi- tion. And under the slower water condition, because of being avail for algae' s living, more algae calcium carbonate will precipitate, and few calcium carbonate will deposit under the condition without algae. Also, under the motionless condition, contribution of calcium carbonate deposit have been compared in the article between the algous environment and without algous

  20. Competition and facilitation between unicellular nitrogen-fixing cyanobacteria and non-nitrogen-fixing phytoplankton species

    NARCIS (Netherlands)

    Agawin, N.S.; Rabouille, S.; Veldhuis, M.; Servatius, L.; Hol, S.; van Overzee, H.M.J.; Huisman, J.

    2007-01-01

    Abstract: Recent discoveries show that small unicellular nitrogen-fixing cyanobacteria are more widespread than previously thought and can make major contributions to the nitrogen budget of the oceans. We combined theory and experiments to investigate competition for nitrogen and light between these

  1. Genetic diversity of the unicellular nitrogen-fixing cyanobacteria UCYN-A and its prymnesiophyte host

    OpenAIRE

    Thompson, A.; Carter, BJ; Turk-Kubo, K; Malfatti, F; F. Azam; Zehr, JP

    2014-01-01

    © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd. Summary: Symbiotic interactions between nitrogen-fixing prokaryotes and photosynthetic eukaryotes are an integral part of biological nitrogen fixation at a global scale. One of these partnerships involves the cyanobacterium UCYN-A, which has been found in partnership with an uncultivated unicellular prymnesiophyte alga in open-ocean and coastal environments. Phylogenetic analysis of the UCYN-A nitrogenase gene (nifH) showed th...

  2. [Carbonic anhydrase of blue-green alga Spirulina platensis].

    Science.gov (United States)

    Komarova, Iu M; Terekhova, I V; Doman, N G; Al'bitskaia, O N

    1976-01-01

    Carboanhydrase (carbonate-hydroliase EC 4.2.1.1.) is found in the extract of Spirulina platensis cells. A linear dependency of the enzyme activity on the protein concentration; pH optimum is found to be 8.0. Specific activity of carboanhydrase is 3 muM/min-mg of protein under the concentration of CO2 of 4-10(-3) M, appearing Michelis constant being 4.9-10(-3) M. The enzyme was stabilized with 10 mM of cisteine, its activity was inhibited by 50% with sulphanylamide (1-10(-5) M), acetazolamide (8--10(-7) M) and Cl- ions (5-10(-2) M). The activity of carboanhydrase, as well as the rate of NaH14CO3 fixation, depended on the pH value of cultural medium.

  3. Distribution and biomass estimation of shell-boring algae in the intertidal area at Goa India

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Sharma, S.; Lande, V.

    The distribution and frequency of shell-boring green and blue-green algae in the intertidal at Goa, India were studied. The green alga Gomontia sp. and the blue green algae Hyella caespitosa Bornet et Flahault, H. gigas Lucas et Golubic...

  4. Nitrogen Fixing Legumes in the Plant Communities

    Directory of Open Access Journals (Sweden)

    M. A.A. Al-Fredan

    2011-01-01

    Full Text Available Problems statement: Numerous authors have used energetic to explain the ecological success of N-fixing plants. Legume biodiversity assessment, species dynamics, nitrogen fixation monitoring and environment impact assessment of these ecological events in Al-Hassa Oasis, Saudi Arabia are rare and need to be continuous and more frequent. Approach: Thus the objectives of this study were to analyze legume abundance within and outside Al-Hassa Oasis and relate it to the distribution of the different genera. Results: Thirty two legume plant species from 20 genera have been recorded within and outside the Oasis. The largest genera were Cassia (4 species, Indigofera (4 and Acacia (3. Annual herbs were the dominant growth form (34% of species recorded, followed by shrubs (28%, perennial herbs (19% and trees (19%. Eighteen alien plant species were recorded (maybe an underestimated number. The nitrogen fixation of the legume plant species in Al-Hassa Oasis was estimated/analyzing the fixing potentiality of these species and nonfixing reference species (Panicum turgidum using the 15N natural abundance method. Species with great nitrogen fixing capacity in Al-Hassa include: Medicago sativa, Vicia faba, Vicia sativa, Melitotus indicus, Dolicus lablab, Melitotus alba and Cliforia ternate. The mean biological fixation contribution of most of the recorded legume plants were high, varying from 3.9% (Indigofera argentea to 64.6% (Medicago sativa. Conclusion: Al-Hassa Oasis is richer than expected based on its location within the desert zone. This study confirms the importance of the Oasis for national flora conservation in the Kingdom. results showed a good potential for use of the 15N natural abundance methodology for evaluating the nitrogen fixation ability of the legume plants under field conditions as well as for the estimation of %Ndfa.

  5. Removal of nutrients by algae from municipal wastewater contaminated with heavy metals

    OpenAIRE

    Aryal, Bigyan

    2015-01-01

    Selected species of algae (green algae and blue green algae) were cultivated in municipal wastewater using PBR (photo-bioreactor) bottles. Uptake of nutrients by these algae species was measured on different dates. From the results of the experiments, it was observed that a combination of certain blue green algae species (cyanobacteria) was able to remove most of the nutrients from the wastewater. The presence of heavy metal ions in the wastewater also affected the nutrient-absorbing capacit...

  6. [DNA homology in various strains of nitrogen-fixing bacteria].

    Science.gov (United States)

    Vardevanian, P O; Minasbekian, L A; Parsadanian, M A

    2000-01-01

    Melting temperature and GC content were evaluated for DNA of some nitrogen-fixing bacteria of Rhizobium leguminosarum and Onobrychis spp. (Adans). The degree of homology between strains of the same species was determined. A combination of thermal denaturing and molecular hybridization can serve as a rapid test for evaluating the genome homology of the organisms compared.

  7. Enriching vermicompost by nitrogen fixing and phosphate solubilizing bacteria.

    Science.gov (United States)

    Kumar, V; Singh, K P

    2001-01-01

    The effect of inoculation of vermicompost with nitrogen-fixing Azotobacter chroococcum strains, Azospirillum lipoferum and the phosphate solubilizing Pseudomonas striata on N and P contents of the vermicompost was assessed. Inoculation of N2 fixing bacteria into vermicompost increased contents of N and P. Enriching vermicompost with rock phosphate improved significantly the available P when inoculated with P. striata. During the incubation period, the inoculated bacterial strains proliferated rapidly, fixed N and solubilized added and native phosphate.

  8. Nitrogen-fixing bacteria in Mediterranean seagrass (Posidonia oceanica) roots

    KAUST Repository

    Garcias Bonet, Neus

    2016-03-09

    Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

  9. Power-Scalable Blue-Green Bessel Beams

    Science.gov (United States)

    2016-02-23

    use high energy pulsed lasers . This scheme would be operationally effective only if the lasers and sources could be mounted on a variety of...near-IR photons or 1.2 X mJ of blue/green photons. In comparison, the conventional approach of using a powerful 10xx nm fiber laser and frequency...convert it to LP0,7 mode of the outer core using a UV -written long period grating (LPG) coupler [11]. The LPG is located 5 cm from the input facet

  10. Marine Algae and Seagrasses of Hatay (Mediterranean, Turkey)

    OpenAIRE

    Aysel, V.; Erdugan, H.; Okudan, E. S.

    2015-01-01

    Abstract In this research, marine algae and seagrasses were investigated in the upper infralittoral zone of Hatay (Turkish Mediterranean coasts). A total of 377 algae and 5 seagrasses were determined. 30 of them belong to blue-green algae (Cyanophyceae), 201 to red algae [Rhodellophyceae (2), Compsopogonophyceae (2), Bangiophyceae (5), Florideophyceae (192)], 73 to brown algae (Fucophyceae), 73 to green algae [Chlorophyceae (5), Ulvophyceae (19), Trentepohliophyceae (1), Cladophorophyceae (24...

  11. Marine Algae and Seagrasses of Hatay (Mediterranean, Turkey)

    OpenAIRE

    Aysel, V.; Erdugan, H.; Okudan, E. S.

    2006-01-01

    Abstract In this research, marine algae and seagrasses were investigated in the upper infralittoral zone of Hatay (Turkish Mediterranean coasts). A total of 377 algae and 5 seagrasses were determined. 30 of them belong to blue-green algae (Cyanophyceae), 201 to red algae [Rhodellophyceae (2), Compsopogonophyceae (2), Bangiophyceae (5), Florideophyceae (192)], 73 to brown algae (Fucophyceae), 73 to green algae [Chlorophyceae (5), Ulvophyceae (19), Trentepohliophyceae (1), Cladophorophyceae (24...

  12. Nutritional And Taste Characteristics Of Algae

    Science.gov (United States)

    Karel, M.; Nakhost, Z.

    1992-01-01

    Report describes investigation of chemical composition of blue-green algae Synechococcus 6311, as well as preparation of protein isolate from green alga Scenedesmus obliquus and incorporation into variety of food products evaluated for taste. Part of program to investigate growth of microalgae aboard spacecraft for use as food.

  13. Unusual radioresistance of nitrogen-fixing cultures of Anabaena strains

    Indian Academy of Sciences (India)

    Harinder Singh; Tonina Fernandes; Shree Kumar Apte

    2010-09-01

    Nitrogen-fixing cultures of two species of the filamentous, heterocystous cyanobacterium Anabaena, namely Anabaena sp. strain L-31 and Anabaena torulosa were found to be highly tolerant to 60Co gamma radiation. No adverse effect on diazotrophic growth and metabolism were observed up to a dose of 5 kGy. At higher doses, radiation tolerance showed a correspondence with the inherent osmotolerance, with Anabaena L-31 being the more radiation tolerant as well as osmotolerant strain. In Anabaena L-31, exposure to 6 kGy of gamma rays resulted in genome disintegration, but did not reduce viability. Irradiation delayed heterocyst differentiation and nitrogen fixation, and marginally affected diazotrophic growth. All the affected parameters recovered after a short lag, without any discernible post-irradiation phenotype. The radiation tolerance of these Gram-negative photoautodiazotrophs is comparable with that of the adiazotrophic photoautotrophic cyanobacterium Chroococcidiopsis or adiazotrophic heterotroph Deinococcus radiodurans. This is the first report of extreme radioresistance in nitrogen-fixing Anabaena cultures.

  14. Marine algae and seagrasses of Tekirdag (Black Sea,Turkey)*

    OpenAIRE

    AYSEL, Veysel; Erdugan, Hüseyin; Dural, Berrin; SükranOkudan, E.

    2015-01-01

    Abstract In this study, marine algae and seagrasses in the upper infralittoral zone of the Black Sea coast of Tekirdag (Turkey) were investigated. A total 156 taxon (153 algae and 3 seagrasses) in species or inferior to the species category were determined. 15 of them belong to blue-green bacteria (Cyanophyta), 84 to red algae (Rhodophyta), 26 to brown algae (Heterokontophyta), 28 to green algae (Chlorophyta) and 3 to marineflowering plants (Magnoliophyta).

  15. Marine algae and seagrasses of Tekirdag (Black Sea,Turkey)*

    OpenAIRE

    AYSEL, Veysel; Erdugan, Hüseyin; Dural, Berrin; SükranOkudan, E.

    2006-01-01

    Abstract In this study, marine algae and seagrasses in the upper infralittoral zone of the Black Sea coast of Tekirdag (Turkey) were investigated. A total 156 taxon (153 algae and 3 seagrasses) in species or inferior to the species category were determined. 15 of them belong to blue-green bacteria (Cyanophyta), 84 to red algae (Rhodophyta), 26 to brown algae (Heterokontophyta), 28 to green algae (Chlorophyta) and 3 to marineflowering plants (Magnoliophyta).

  16. Enumeration and Identification of Nitrogen-Fixing Bacteria from Forage Grass Roots

    OpenAIRE

    Wright, Sara F.; Weaver, R. W.

    1981-01-01

    Root-soil cores were collected from forage grasses growing in a subtropical region of Texas and tested for acetylene reduction activity. The population density of nitrogen-fixing bacteria was measured, using various media and incubation conditions. Bacteria were confirmed as nitrogen fixing, using the acetylene reduction assay, and were classified according to standard biochemical and cultural methods. The majority of the nitrogen-fixing bacteria isolated from roots were Enterobacter cloacae ...

  17. Retinal oximeter for the blue-green oximetry technique

    Science.gov (United States)

    Denninghoff, Kurt R.; Sieluzycka, Katarzyna B.; Hendryx, Jennifer K.; Ririe, Tyson J.; Deluca, Lawrence; Chipman, Russell A.

    2011-10-01

    Retinal oximetry offers potential for noninvasive assessment of central venous oxyhemoglobin saturation (SO2) via the retinal vessels but requires a calibrated accuracy of +/-3% saturation in order to be clinically useful. Prior oximeter designs have been hampered by poor saturation calibration accuracy. We demonstrate that the blue-green oximetry (BGO) technique can provide accuracy within +/-3% in swine when multiply scattered light from blood within a retinal vessel is isolated. A noninvasive on-axis scanning retinal oximeter (ROx-3) is constructed that generates a multiwavelength image in the range required for BGO. A field stop in the detection pathway is used in conjunction with an anticonfocal bisecting wire to remove specular vessel reflections and isolate multiply backscattered light from the blood column within a retinal vessel. This design is tested on an enucleated swine eye vessel and a retinal vein in a human volunteer with retinal SO2 measurements of ~1 and ~65%, respectively. These saturations, calculated using the calibration line from earlier work, are internally consistent with a standard error of the mean of +/-2% SO2. The absolute measures are well within the expected saturation range for the site (-1 and 63%). This is the first demonstration of noninvasive on-axis BGO retinal oximetry.

  18. Blue-Green Colour Categorisation in Mandarin-English Speakers

    Directory of Open Access Journals (Sweden)

    Emily Joanne Hird

    2012-05-01

    Full Text Available Observers are faster to detect a target among a set of distracters if the targets and distracters come from different colour categories. This cross-boundary advantage seems to be limited to the right visual field, which is consistent with the dominance of the left hemisphere for language processing. Here we study whether a similiar visual field advantage is found in Mandarin, a language which uses a logographic system. Forty late Mandarin-English bilinguals performed a blue-green colour categorisation task, in a blocked design, in their first language (L1: Mandarin or second language (L2: English. Eleven colour singletons ranging from blue to green were presented for 160ms, randomly in the left visual field (LVF or in the right visual field (RVF. We find that reaction times at the colour boundary were on average about 100 ms shorter in the LVF compared to the RVF, but only when the task was preformed in Mandarin as opposed to English. The apparent discrepancy with previous findings is conceivably due to the script nature of two languages: Mandarin logographic characters are analysed visuo-orthographically in the right fusiform gyrus [Guo and Burgund 2010, Brain Lang 115].

  19. What Does It Take to Evolve A Nitrogen-Fixing Endosymbiosis?

    NARCIS (Netherlands)

    Geurts, Rene; Xiao, Ting Ting; Reinhold-Hurek, Barbara

    2016-01-01

    Plant rhizo- and phyllospheres are exposed to a plethora of nitrogen-fixing bacteria, providing opportunities for the establishment of symbiotic associations. Nitrogen-fixing endosymbioses are most profitable and have evolved more than ten times in the angiosperms. This suggests that the evolutio

  20. What Does It Take to Evolve A Nitrogen-Fixing Endosymbiosis?

    NARCIS (Netherlands)

    Geurts, Rene; Xiao, Ting Ting; Reinhold-Hurek, Barbara

    2016-01-01

    Plant rhizo- and phyllospheres are exposed to a plethora of nitrogen-fixing bacteria, providing opportunities for the establishment of symbiotic associations. Nitrogen-fixing endosymbioses are most profitable and have evolved more than ten times in the angiosperms. This suggests that the

  1. Isolation and Characterisation of Endophytic Nitrogen Fixing Bacteria in Sugarcane.

    Science.gov (United States)

    Muangthong, Ampiga; Youpensuk, Somchit; Rerkasem, Benjavan

    2015-04-01

    Endophytic nitrogen fixing bacteria were isolated from the leaves, stems and roots of industrial variety (cv. U-Thong 3; UT3), wild and chewing sugarcane plants grown for 6 weeks in nitrogen (N)-free sand. Eighty nine isolates of endophytic bacteria were obtained on N-free agar. An acetylene reduction assay (ARA) detected nitrogenase activity in all 89 isolates. Three isolates from the chewing (C2HL2, C7HL1 and C34MR1) sugarcane and one isolate from the industrial sugarcane (UT3R1) varieties were characterised, and their responses to different yeast extract concentrations were investigated. Three different responses in nitrogenase activity were observed. Isolates C2HL2 and C7HL1 exhibited major increases with the addition of 0.005% yeast extract, C34MR1 exhibited no response, and UT3R1 exhibited a significant decrease in nitrogenase activity with 0.005% yeast extract. In all the isolates, nitrogenase activity decreased with further increase of the yeast extract to 0.05%. The highest nitrogenase activity was observed in isolates C2HL2 and C7HL1, which had 16S rRNA gene sequences that were closely related to Novosphingobium sediminicola and Ochrobactrum intermedium, respectively.

  2. A curious case of blue-green discoloration in a middle-aged indian man: Chromhidrosis

    OpenAIRE

    Ghosh, Sudip Kumar; Rudra, Olympia; Kar, Rajarshi; Ghosh, Arghyaprasun; Agarwal, Megha

    2015-01-01

    Introduction: Chromhidrosis is a rare sweat gland disorder charac­terized by the excretion of colored sweat. It can be classified as apocrine, true eccrine, and pseudochromhidrosis. Amongst the different types of chromhidrosis, green chromhidrosis is extremely rare. We describe herein a case of blue green chromhidrosis induced by ingestion of homeopathic medicine. Case report: A middle aged man presented to us with blue green discoloration of hands and feet. T...

  3. Occurrence and purification on microcystis species. Biodegradation of micropollutant producing from blue-green algae using effective microorganism in bio-film; Aoko/sono hassei to joka taisaku. Seibutsumaku no yuyo biseibutsu ni yoru aoko no bunkai to kodo joka

    Energy Technology Data Exchange (ETDEWEB)

    Inamori, Y. [National Inst. for Environmental Studies, Tsukuba (Japan); Akimoto, S. [Tsukuba Univ., (Japan). Graduate School

    1994-09-10

    The bio-film method is to utilize the purification force of a bio-film consisted of the microorganisms such as the bacteria, fungi, protozoa, micrometazoa and so forth, which are formed on the surface of the gravels at a bottom part of the river, for a polluted water purification. This bio-film method was developed for a purpose of to make its activity proceed artificially and efficiently insides the tank. If these protozoa and metazoa occur as a substantial quantity in the bio-film treatment method of the polluted lake water, as they exhibit a large force to decompose and make inorganic the algae, their mass colonization is extremely important. In actual site practice, because the bio-film quantity and the bio-phase fluctuate substantially depending on the inflowing pollution load quantity and the temperature, an investigation of the manipulation method, by which the bio-phase corresponding to an inflow condition can be dominant, is necessary. In addition, in order to effectively decompose and remove the 2-MTB, microcystin RR and so forth, because securing the colonization field for the useful microorganisms is essential, a development of the adhesion carrier in which the useful microorganisms are easy to live, is also needed. 9 refs., 5 figs., 2 tabs.

  4. Cryptochrome as a sensor of the blue/green ratio of natural radiation in Arabidopsis.

    Science.gov (United States)

    Sellaro, Romina; Crepy, María; Trupkin, Santiago Ariel; Karayekov, Elizabeth; Buchovsky, Ana Sabrina; Rossi, Constanza; Casal, Jorge José

    2010-09-01

    Green light added to blue light has been proposed to shift cryptochromes from their semireduced active form to the reduced, inactive state. Whether the increased proportion of green light observed under leaf canopies compared to open places reduces cryptochrome-mediated effects remained to be elucidated. Here we report that the length of the hypocotyl of Arabidopsis (Arabidopsis thaliana) seedlings grown under controlled conditions decreased linearly with increasing blue/green ratios of the light within the range of ratios found in natural environments. This effect was stronger under higher irradiances. We developed a model, parameterized on the basis of field experiments including photoreceptor mutants, where hypocotyl growth of seedlings exposed to different natural radiation environments was related to the action and interaction of phytochromes and cryptochromes. Adding the blue/green ratio of the light in the term involving cryptochrome activity improved the goodness of fit of the model, thus supporting a role of the blue/green ratio under natural radiation. The blue/green ratio decreased sharply with increasing shade by green grass leaves to one-half of the values observed in open places. The impact of blue/green ratio on cryptochrome-mediated inhibition of hypocotyl growth was at least as large as that of irradiance. We conclude that cryptochrome is a sensor of blue irradiance and blue/green ratio.

  5. Let them eat algae

    Energy Technology Data Exchange (ETDEWEB)

    Ciferri, O.

    1981-09-24

    The blue-green alga, Spirulina appears to be one of the candidates for the solution of the global problems of energy, food and chemical feedstock supplies. The harvesting of algae from Lake Texcoco, Mexico for the making of bread was noted in the 16th century by the Spanish and over 400 years later, dried biscuits made from algae were noted in Chad. Recent investigations have shown that the alga contains a very high proportion of protein - even higher than soya beans and is of high quality. A pilot plant covering 2 hectares for culturing Spirulina in a closed system is under construction in Italy. The polyethylene tubes will function as solar collectors and so extend the production season of the algae in more temperate regions.

  6. Nitrogen fixed by cyanobacteria is utilized by deposit-feeders.

    Directory of Open Access Journals (Sweden)

    Agnes M L Karlson

    Full Text Available Benthic communities below the photic zone depend for food on allochthonous organic matter derived from seasonal phytoplankton blooms. In the Baltic Sea, the spring diatom bloom is considered the most important input of organic matter, whereas the contribution of the summer bloom dominated by diazotrophic cyanobacteria is less understood. The possible increase in cyanobacteria blooms as a consequence of eutrophication and climate change calls for evaluation of cyanobacteria effects on benthic community functioning and productivity. Here, we examine utilization of cyanobacterial nitrogen by deposit-feeding benthic macrofauna following a cyanobacteria bloom at three stations during two consecutive years and link these changes to isotopic niche and variations in body condition (assayed as C:N ratio of the animals. Since nitrogen-fixing cyanobacteria have δ(15N close to -2‰, we expected the δ(15N in the deposit-feeders to decrease after the bloom if their assimilation of cyanobacteria-derived nitrogen was substantial. We also expected the settled cyanobacteria with their associated microheterotrophic community and relatively high nitrogen content to increase the isotopic niche area, trophic diversity and dietary divergence between individuals (estimated as the nearest neighbour distance in the benthic fauna after the bloom. The three surface-feeding species (Monoporeia affinis, Macoma balthica and Marenzelleria arctia showed significantly lower δ(15N values after the bloom, while the sub-surface feeder Pontoporeia femorata did not. The effect of the bloom on isotopic niche varied greatly between stations; populations which increased niche area after the bloom had better body condition than populations with reduced niche, regardless of species. Thus, cyanobacterial nitrogen is efficiently integrated into the benthic food webs in the Baltic, with likely consequences for their functioning, secondary production, transfer efficiency, trophic

  7. Recent advances in nitrogen-fixing acetic acid bacteria.

    Science.gov (United States)

    Pedraza, Raúl O

    2008-06-30

    Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects

  8. Nitrogen fixed by cyanobacteria is utilized by deposit-feeders.

    Science.gov (United States)

    Karlson, Agnes M L; Gorokhova, Elena; Elmgren, Ragnar

    2014-01-01

    Benthic communities below the photic zone depend for food on allochthonous organic matter derived from seasonal phytoplankton blooms. In the Baltic Sea, the spring diatom bloom is considered the most important input of organic matter, whereas the contribution of the summer bloom dominated by diazotrophic cyanobacteria is less understood. The possible increase in cyanobacteria blooms as a consequence of eutrophication and climate change calls for evaluation of cyanobacteria effects on benthic community functioning and productivity. Here, we examine utilization of cyanobacterial nitrogen by deposit-feeding benthic macrofauna following a cyanobacteria bloom at three stations during two consecutive years and link these changes to isotopic niche and variations in body condition (assayed as C:N ratio) of the animals. Since nitrogen-fixing cyanobacteria have δ(15)N close to -2‰, we expected the δ(15)N in the deposit-feeders to decrease after the bloom if their assimilation of cyanobacteria-derived nitrogen was substantial. We also expected the settled cyanobacteria with their associated microheterotrophic community and relatively high nitrogen content to increase the isotopic niche area, trophic diversity and dietary divergence between individuals (estimated as the nearest neighbour distance) in the benthic fauna after the bloom. The three surface-feeding species (Monoporeia affinis, Macoma balthica and Marenzelleria arctia) showed significantly lower δ(15)N values after the bloom, while the sub-surface feeder Pontoporeia femorata did not. The effect of the bloom on isotopic niche varied greatly between stations; populations which increased niche area after the bloom had better body condition than populations with reduced niche, regardless of species. Thus, cyanobacterial nitrogen is efficiently integrated into the benthic food webs in the Baltic, with likely consequences for their functioning, secondary production, transfer efficiency, trophic interactions, and

  9. Nitrogen fixing bacterial diversity in a tropical estuarine sediments.

    Science.gov (United States)

    Thajudeen, Jabir; Yousuf, Jesmi; Veetil, Vipindas Puthiya; Varghese, Sherin; Singh, Arvind; Abdulla, Mohamed Hatha

    2017-02-01

    Microorganisms play a significant role in biogeochemical cycles, especially in the benthic and pelagic ecosystems. Role of environmental parameters in regulating the diversity, distribution and physiology of these microorganisms in tropical marine environment is not well understood. In this study, we have identified dinitrogen (N2) fixing bacterial communities in the sediments by constructing clone libraries of nitrogenase (nifH) gene from four different stations in the Cochin estuary, along the southeastern Arabian Sea. N2 fixing bacterial clones revealed that over 20 putative diazotrophs belong to alpha-, beta-, gamma-, delta- and epsilon- proteobacteria and firmicutes. Predominant genera among these were Bradyrhizobium sp. (α-proteobacteria), Dechloromonas sp. (β-proteobacteria); Azotobactor sp., Teredinibacter sp., Methylobacter sp., Rheinheimera sp. and Marinobacterium sp. (γ-proteobacteria); Desulfobacter sp., Desulfobulbus sp. and Desulfovibrio sp. (δ -proteobacteria); Arcobacter sp. and Sulfurospirillum sp. (ε-proteobacteria). Nostoc sp. was solely identified among the cyanobacterial phylotype. Nitrogen fixing Sulfate reducing bacteria (SRBs) such as Desulfobulbus sp., Desulfovibrio sp., Desulfuromonas sp., Desulfosporosinus sp., Desulfobacter sp., were also observed in the study. Most of the bacterial nifH sequences revealed that the identities of N2 fixing bacteria were less than 95% similar to that available in the GenBank database, which suggested that the sequences were of novel N2 fixing microorganisms. Shannon-Weiner diversity index of nifH gene ranged from 2.95 to 3.61, indicating an inflated diversity of N2 fixing bacteria. Canonical correspondence analysis (CCA) implied positive correlation among nifH diversity, N2 fixation rate and other environmental variables.

  10. Upstream factors affecting Tualatin River algae—Tracking the 2008 Anabaena algae bloom to Wapato Lake, Oregon

    Science.gov (United States)

    Rounds, Stewart A.; Carpenter, Kurt D.; Fesler, Kristel J.; Dorsey, Jessica L.

    2015-12-17

    Significant Findings A large bloom that included floating mats of the blue-green algae Anabaena flos-aquae occurred in the lower 20 miles of the Tualatin River in northwestern Oregon between July 7 and July 17, 2008.

  11. Spirulina: The Alga That Can End Malnutrition.

    Science.gov (United States)

    Fox, Ripley D.

    1985-01-01

    One approach to eliminating malnutrition worldwide is to grow spirulina in recycled village wastes. Spirulina is a blue-green alga and a natural concentrated food. Spirulina can give poor villages a nutritional food supplement they can grow themselves and can reduce infectious disease at the same time. (Author/RM)

  12. Spirulina: The Alga That Can End Malnutrition.

    Science.gov (United States)

    Fox, Ripley D.

    1985-01-01

    One approach to eliminating malnutrition worldwide is to grow spirulina in recycled village wastes. Spirulina is a blue-green alga and a natural concentrated food. Spirulina can give poor villages a nutritional food supplement they can grow themselves and can reduce infectious disease at the same time. (Author/RM)

  13. The Glaucophyta: the blue-green plants in a nutshell

    Directory of Open Access Journals (Sweden)

    Christopher Jackson

    2015-07-01

    Full Text Available The Glaucophyta is one of the three major lineages of photosynthetic eukaryotes, together with viridiplants and red algae, united in the presumed monophyletic supergroup Archaeplastida. Glaucophytes constitute a key algal lineage to investigate both the origin of primary plastids and the evolution of algae and plants. Glaucophyte plastids possess exceptional characteristics retained from their cyanobacterial ancestor: phycobilisome antennas, a vestigial peptidoglycan wall, and carboxysome-like bodies. These latter two traits are unique among the Archaeplastida and have been suggested as evidence that the glaucophytes diverged earliest during the diversification of this supergroup. Our knowledge of glaucophytes is limited compared to viridiplants and red algae, and this has restricted our capacity to untangle the early evolution of the Archaeplastida. However, in recent years novel genomic and functional data are increasing our understanding of glaucophyte biology. Diverse comparative studies using information from the nuclear genome of Cyanophora paradoxa and recent transcriptomic data from other glaucophyte species provide support for the common origin of Archaeplastida. Molecular and ultrastructural studies have revealed previously unrecognized diversity in the genera Cyanophora and Glaucocystis. Overall, a series of recent findings are modifying our perspective of glaucophyte diversity and providing fresh approaches to investigate the basic biology of this rare algal group in detail.

  14. [Toxicological evaluation of biopreparations on the basis of nitrogen-fixing bacteria].

    Science.gov (United States)

    Omel'ianets', T H; Holovach, T M

    2009-01-01

    A comparative analysis of results of toxicological research of microbiological preparations on the basis of different species of nitrogen-fixing microorganisms of Azotobacter, Agrobacterium, Azospirillum general and pathogenic properties of strains-producers has been carried out. A possibility to improve methodical principles of toxicological estimation and hygienic regulation of associative nitrogen-fixing microorganisms-producers and preparations on their basis in the industrial objects and environment is substantiated. The paper is presented in Ukrainian.

  15. Population of Aerobic Heterotrophic Nitrogen-Fixing Bacteria Associated with Wetland and Dryland Rice

    OpenAIRE

    Barraquio, W.L.; de Guzman, M. R.; Barrion, M.; Watanabe, I.

    1982-01-01

    Nitrogen-fixing activity and populations of nitrogen-fixing bacteria associated with two varieties of rice grown in dryland and wetland conditions were measured at various growth stages during the dry season. Acetylene reduction activities were measured both in the field and for the hydroponically grown rice, which was transferred from the field to water culture 1 day before assay. The activities measured by both methods were higher in wetland than in dryland rice. The population of nitrogen-...

  16. Synthesis and Strong Blue-Green Emission Properties of ZnO Nanowires

    Institute of Scientific and Technical Information of China (English)

    刘东方; 唐东升; 慈立杰; 闫小琴; 梁迎新; 周振平; 袁华军; 周维亚; 王刚

    2003-01-01

    ZnO nanowires were catalytically grown on Au-coated silicon substrates by the carbon thermal reduction method.The process involved addition of a low partial pressure of hydrogen sulphide to the argon carrier flow. The addition of H2S led to the higher yield and longer nanowires without any morphology change, and no sulphuric content was observed by the energy dispersive x-ray spectroscopy in the resulting nanowires. The nanowires exhibited strong blue-green emission at room temperature and an increasing intensity when the partial pressure of H2S was raised. The temperature-dependent photoluminescence spectra show that intensity of the blue-green emission,almost without shift, decreases slowly with increasing temperature. Heat treatments indicated that quenching resulted in a higher ratio of blue-green emission to ultraviolet emission.

  17. THE SOIL ALGAE OF CIBODAS FOREST RESERVE

    Directory of Open Access Journals (Sweden)

    Anne Johnson

    2014-01-01

    Full Text Available Three species of green algae and one blue-green alga were recorded from eight samples of soil found associated with bryophytes in the Cibodas Forest Reserve. Chemical analysis of the soil showed severe leaching of soluable mineral substances associated with a low pH. The low light intensity under forest conditions and the low pH may account for the limited algal flora.

  18. Raman-Shifted XeCl Laser Development for a Spaceborne Blue-Green Source.

    Science.gov (United States)

    1982-02-01

    RAMAN-SHIFTED XeCI LASER DEVELOPMENT FOR A SPACEBORNE BLUE-GREEN SOURCE E. A. Stappaerts, M. J. Plummer, W. H. Long, Jr., S. J. Brosnan, H. Komine, and J...TITLE (and S.britJ S. TYPE OF REPORT 6 PEPIOD COVEPED Raman-Shifted XeCl Laser Development for a Technical Report Spaceborne Blue-Green Source: Interim...0.7% cm𔃻 312 nm I0 A 50 ns/DIV. FIGURE 5.3-1 MEASURED GAIN AND LOSS IN XeC1 87 81-34 AD-A133 078 RAMAN-SHIFED XEC LASER DEVELOPMENT FOR A

  19. Cloning and expression of an amylase gene from Bacillus sp ...

    African Journals Online (AJOL)

    SAM

    2014-08-06

    Aug 6, 2014 ... from a bacterial cell, a bacterium was isolated that uses natural starch as sole carbon source. The organism ... 2010).They improve soil structure, texture, porosity, air ... fertilizers are nitrogen fixing bacteria, blue green algae,.

  20. Pathophysiology and Toxicokinetic Studies of Blue-Green Algae Intoxication in the Swine Model

    Science.gov (United States)

    1991-06-26

    Wiley, New York, pp. 100 109. Fox, P. R. (1986) Cor pulmonale . In: Kirk, R. W. (ed.), Current Veterinary Therapy IX: Small Animal Practice, Vol. 9. W...es ind a Tra~ cor Norflhern 1:%M( 30H) . Nomninal parameters for data acquINitIol1 were 5WX daita Points. acýquis: ~ion timeTi 10 ins, low filter 0R5 It

  1. Phycobilisomes from the blue-green algae Aphanizomenon flos-aquae and Anabaena variabilis.

    Science.gov (United States)

    Bekasova, O D; Shubin, L M; Evstigneev, V B

    1979-01-01

    Phycobilisomes (PBS) were isolated from Aphanizomenon flos-aquae and Anabaena variabilis. The absorption spectra and second derivative of the absorption spectra of isolated PBS indicate the presence of phycoerythrocyanin, and allophycocyanin. The fluorescence spectra of PBS were measured at room temperature and -196 degrees C. Undamaged PBS have the principal fluorescence maximum in the region of 660 nm at room temperature and in the region of 685-690 nm at -196 degrees. When the PBS were heated from ) to 60 degrees the fluorescence at 685-690 nm disappeared and it increased in the region of 650-660 nm. This is apparently due to disruption of the structure of PBS, which results in a disturbance in the migration of energy along the chain phycoerythrocyanin leads to phycocyanin leads to allophycocyanin.

  2. Pathophysiology and Toxicokinetic Studies of Blue-Green Algae Intoxication in the Swine Model

    Science.gov (United States)

    1986-11-21

    Arginase Activity in Twelve Tissues &ad Serum- From- Market Height Swine-by a Direct Colorimetric Method o o o * # 145 Introduction .04...MATYRIALS RND METHODS Isotops Tritiated water was purchased from New England Nuclear Research Producto Company, Boston, MA, USA. The specific activity was 1...ARGINASI ACTI.VITY IN TWELVE TISSUES AND SERUM FROM MARKET WEIGHT SWINE BY A DIRECT COLORIMETRIC MEITHOD Randall A. Lovell, DVM Walter 1. Hoffmann, DYM

  3. An Appreciation of Learning Disabilities: The Value of Blue-Green Algae.

    Science.gov (United States)

    Gerber, Michael M.

    2000-01-01

    This review of the history of learning disabilities (LD) suggests that creation of the LD category has served scientific, if not always, policy purposes. It finds that 40 years of research have produced inventive, creative tools that benefit both investigation and intervention and, most importantly, a better understanding of individual…

  4. Pathophysiology and Toxicokinetic Studies of Blue-Green Algae Intoxication in the Swine Model

    Science.gov (United States)

    1989-09-26

    inhibition of synthesis of the glutathione S-transferase 3 enzymes. Since GSH is also a cofactor for glutathione peroxidase , its depletion can promote...can fire at rates of 20 I to 50 Hz (Zaimis, 1976). Of the 4 animals administered 800 pg/kg. none had 757. return of the 3 amplitude and all animals...mice were pretreated by fedJ.rg ( glutathione replete), fasting (mild GSH depletion), fasting and n-aLetylcysteine (depletes GSH), or fasting and

  5. Solution structure of reduced plastocyanin from the blue-green alga Anabaena variabilis

    DEFF Research Database (Denmark)

    Badsberg, U; Jørgensen, A.M.; Gesmar, H

    1996-01-01

    The three-dimensional solution structure of plastocyanin from Anabaena variabilis (A.v.PCu) has been determined by nuclear magnetic resonance spectroscopy. Sixty structures were calculated by distance geometry from 1141 distance restraints and 46 dihedral angle restraints. The distance geometry s...

  6. Solution Structure of Reduced Plastocyanin from the Blue-Green Alga Anabaena Variabilis

    DEFF Research Database (Denmark)

    Led, J.J.; Badsberg, U.; Jørgensen, A.M.

    1996-01-01

    The three-dimensional solution structure of plastocyanin from Anabaena variabilis (A.v. PCu) has been determined by nuclear magnetic resonance spectroscopy. Sixty structures were calculated by distance geometry from 1141 distance restraints and 46 dihedral angle restraints. The distance geometry ...

  7. An Appreciation of Learning Disabilities: The Value of Blue-Green Algae.

    Science.gov (United States)

    Gerber, Michael M.

    2000-01-01

    This review of the history of learning disabilities (LD) suggests that creation of the LD category has served scientific, if not always, policy purposes. It finds that 40 years of research have produced inventive, creative tools that benefit both investigation and intervention and, most importantly, a better understanding of individual…

  8. Native Mussels Alter Nutrient Availability and Reduce Blue-Green Algae Abundance

    Science.gov (United States)

    Nutrient cycling is a key process that ties all organisms together. This is especially apparent in stream environments in which nutrients are taken up readily and cycled through the system in a downstream trajectory. Ecological stoichiometry predicts that biogeochemical cycles of...

  9. Photorecovery of gamma irradiated cultures of blue-green alga, Anacystis nidulans.

    Science.gov (United States)

    Asato, Y.

    1971-01-01

    Evidence is given for photorecovery of Anacystis nidulans after exposures to Co 60 gamma radiation. After irradiation the levels of viable cells were higher in cultures kept in white light than in cultures kept dark for 24 hr. The post-irradiation survival rate increase after 30-min exposures to visible light is demonstrated in cultures irradiated with 35 krad. An increase in survival rates was not observed after exposures to ?red' light.

  10. Effect of supplementation of blue green alga (Spirulina) on outcome of pregnancy in rats.

    Science.gov (United States)

    Kapoor, R; Mehta, U

    1993-01-01

    To study the supplementary effect of Spirulina, pregnant rats were fed 5 different kinds of diets (casein, Spirulina, wheat gluten, Spirulina + wheat gluten, Spirulina-without additional vitamins and minerals), each providing 22% protein during the period of pregnancy. The outcome of pregnancy was assessed from litter and dams' weight and litter size. Maternal weight gain was found to be maximum with Spirulina + wheat gluten and least with the wheat gluten diet. Rats receiving Spirulina containing diets produced significantly (p Spirulina containing diet groups produced pups with birth weights comparable to those of casein. Spirulina appears to be a good dietary supplement during pregnancy.

  11. Pathophysiology and Toxicokinetic Studies of Blue-Green Algae Intoxication in the Swine Model

    Science.gov (United States)

    1987-08-31

    WA M i VIii III - 6 - The contribtition of the unsaturation present in the N-methy! dehydroalanine residue to toxicity was determined for MCYST-A...lyophilized Anabaena flos- agua cells. Using purified antx-a(s), the equilibrium (kd), "phosphorylation" (k2 ), and inhibition (k1) constants for tnhibition of...Microcystis aeruginosa, Anabaena flos- aguae and Aphanizomenon flos- aguae . S. Afr. J. Sci. 78:367-372, 1982. Carmichael, W. W.: Isolation, culture and toxic,ty

  12. Volatile fatty acid recovery by anaerobic fermentation from blue-green algae: Effect of pretreatment.

    Science.gov (United States)

    Cho, Hyun Uk; Kim, Hye Gyeong; Kim, Young Mo; Park, Jong Moon

    2017-05-17

    The aims of this study were to quantify how pretreatment affects production of volatile fatty acids (VFAs) from cyanobacterial biomass and production of subsequent microbial lipid by an oleaginous microorganism that uses the VFAs as carbon sources. The highest biomass solubilization was obtained using thermal-alkaline (th-alkaline) pretreatment (33.1%), followed by alkaline pretreatment (29.1%), and thermal pretreatment (7.2%), but the highest VFA yield was obtained using alkaline pretreatment (0.54±0.02g/gVS), followed by the untreated condition (0.47±0.03g/gVS), and th-alkaline pretreatment (0.44±0.02g/gVS). Although VFA yield was higher using alkaline pretreatment condition than in the untreated condition, the difference was not great. However, lipid productivity by Cryptococcus curvatus after the alkaline pretreatment condition was 2.0-fold higher than that under the untreated condition. This study confirmed the feasibility of using biologically produced VFAs from cyanobacterial biomass for microbial lipid production by the oleaginous microorganism. Copyright © 2017. Published by Elsevier Ltd.

  13. Effects of three different PAHs on nitrogen-fixing bacterial diversity in mangrove sediment.

    Science.gov (United States)

    Sun, Fu-Lin; Wang, You-Shao; Sun, Cui-Ci; Peng, Ya-Lan; Deng, Chao

    2012-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are of great environmental and human health concerns due to their widespread occurrence, persistence and carcinogenic properties. There is now compelling evidence that the mangrove sediment microbial structure is susceptible to PAHs contamination. The study aimed to assess the effects of PAHs on the nitrogen-fixing bacterial community of mangrove sediment. Three types of PAHs, naphthalene (NAP), a two-ring PAH; fluorene (FLU), a three-ring PAH; and pyrene (PYR), a four-ring PAH; were applied at three doses. After 7 and 24 days of incubation, the nitrogen-fixing bacterial population and diversity were evidenced in the nifH gene polymerase chain reaction denaturing gradient gel electrophoresis profile. DGGE pattern shows that the nitrogen-fixing bacterial community changed significantly with the types and doses of PAHs, and the incubation time. As far as single PAH is concerned, high concentration of PAH has larger impact on the nitrogen-fixing bacteria than low concentration of PAH. Besides, among the three types of PAHs, NAP has the greatest short term toxicity; PYR has the strongest long-term impact, whereas FLU has relatively higher long-time effect. Multidimensional scaling analysis and correspondence analysis are two reliable multivariate analysis methods for investigating the relationship between the nitrogen-fixing bacterial community and PAHs contamination. Investigating the effect of PAHs on the nitrogen-fixing bacterial diversity could yield useful information for understanding the process of biogeochemical cycling of nitrogen in mangrove sediment. The present study reveals that nitrogen-fixing bacterial community can be used as an important parameter indicating the impact of PAHs on mangrove sediment ecosystem.

  14. Fluorescence action spectra of algae and bean leaves at room and at liquid nitrogen temperatures

    NARCIS (Netherlands)

    Goedheer, J.C.

    1965-01-01

    Fluorescence action spectra were determined, both at room temperature and at liquid nitrogen temperature, with various blue-green, red and green algae, and greening bean leaves. The action spectra of algae were established with samples of low light absorption as well as dense samples. Fluorescence

  15. Identification by Suppression Subtractive Hybridization of Frankia Genes Induced under Nitrogen-Fixing Conditions▿ †

    OpenAIRE

    Yamaura, Masatoshi; UCHIUMI, Toshiki; Higashi, Shiro; Abe, Mikiko; Kucho, Ken-ichi

    2010-01-01

    Frankia is an actinobacterium that fixes nitrogen under both symbiotic and free-living conditions. We identified genes upregulated in free-living nitrogen-fixing cells by using suppression subtractive hybridization. They included genes with predicted functions related to nitrogen fixation, as well as with unknown function. Their upregulation was a novel finding in Frankia.

  16. Complete Genome Sequence of Bradyrhizobium diazoefficiens USDA 122, a Nitrogen-Fixing Soybean Symbiont

    Science.gov (United States)

    Sugawara, Masayuki; Tsukui, Takahiro; Kaneko, Takakazu; Ohtsubo, Yoshiyuki; Sato, Shusei; Nagata, Yuji; Tsuda, Masataka; Mitsui, Hisayuki

    2017-01-01

    ABSTRACT We report the complete genome sequence of Bradyrhizobium diazoefficiens USDA 122, a nitrogen-fixing soybean symbiont. The genome consists of a 9.1 Mb circular chromosome, and 8,551 coding sequences (CDSs) were predicted on the genome. The sequence will provide insight into the evolution of rhizobial genome, and the symbiotic compatibility with host plants. PMID:28254989

  17. A nodule-specific protein secretory pathway required for nitrogen-fixing symbiosis

    NARCIS (Netherlands)

    Wang, D.; Griffitts, J.; Starker, C.; Fedorova, E.; Limpens, E.H.M.; Ivanov, S.E.; Bisseling, T.; Long, S.

    2010-01-01

    The nitrogen-fixing symbiosis between Sinorhizobium meliloti and its leguminous host plant Medicago truncatula occurs in a specialized root organ called the nodule. Bacteria that are released into plant cells are surrounded by a unique plant membrane compartment termed a symbiosome. We found that in

  18. The optimum energy harvest efficiency of nitrogen fixing hydrophyte: Azolla pinnata

    Energy Technology Data Exchange (ETDEWEB)

    Tennakone, K. (Institute of Fundamental Studies, Kandy (LK) Ruhuna Univ., Matara (LK). Dept. of Physics); Punchihewa, S.; Jayasuriya, A.C. (Institute of Fundamental Studies, Kandy (LK))

    1989-01-01

    Azolla is a nitrogen fixing hydrophyte that can be cultivated in absence of nitrogenous fertilizer. It is found that when biomass is continuously harvested from a culture of Azolla, solar energy can be converted at an optimum efficiency of 1.1%. (author).

  19. Draft Genome Sequence of Frankia sp. Strain BCU110501, a Nitrogen-Fixing Actinobacterium Isolated from Nodules of Discaria trinevis

    Science.gov (United States)

    Wall, Luis G.; Beauchemin, Nicholas; Cantor, Michael N.; Chaia, Eugenia; Chen, Amy; Detter, J. Chris; Furnholm, Teal; Ghodhbane-Gtari, Faten; Goodwin, Lynne; Gtari, Maher; Han, Cliff; Han, James; Huntemann, Marcel; Hua, Susan Xinyu; Ivanova, Natalia; Kyrpides, Nikos; Markowitz, Victor; Mavrommatis, Kostas; Mikhailova, Natalia; Nordberg, Henrik P.; Nouioui, Imen; Ovchinnikova, Galina; Pagani, Ioanna; Pati, Amrita; Sen, Arnab; Sur, Saubashya; Szeto, Ernest; Thakur, Subarna; Wei, Chia-Lin; Woyke, Tanja

    2013-01-01

    Frankia forms a nitrogen-fixing symbiosis with actinorhizal plants. We report a draft genome sequence for Frankia sp. strain BCU110501, a nitrogen-fixing actinobacterium isolated from nodules of Discaria trinevis grown in the Patagonia region of Argentina. PMID:23846281

  20. Draft Genome Sequence of Frankia sp. Strain BMG5.12, a Nitrogen-Fixing Actinobacterium Isolated from Tunisian Soils.

    Science.gov (United States)

    Nouioui, Imen; Beauchemin, Nicholas; Cantor, Michael N; Chen, Amy; Detter, J Chris; Furnholm, Teal; Ghodhbane-Gtari, Faten; Goodwin, Lynne; Gtari, Maher; Han, Cliff; Han, James; Huntemann, Marcel; Hua, Susan Xinyu; Ivanova, Natalia; Kyrpides, Nikos; Markowitz, Victor; Mavrommatis, Kostas; Mikhailova, Natalia; Nordberg, Henrik P; Ovchinnikova, Galina; Pagani, Ioanna; Pati, Amrita; Sen, Arnab; Sur, Saubashya; Szeto, Ernest; Thakur, Subarna; Wall, Luis; Wei, Chia-Lin; Woyke, Tanja; Tisa, Louis S

    2013-07-11

    Members of the actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a draft genome sequence for Frankia sp. strain BMG5.12, a nitrogen-fixing actinobacterium isolated from Tunisian soils with the ability to infect Elaeagnus angustifolia and Myrica gale.

  1. Biological importance of marine algae.

    Science.gov (United States)

    El Gamal, Ali A

    2010-01-01

    Marine organisms are potentially prolific sources of highly bioactive secondary metabolites that might represent useful leads in the development of new pharmaceutical agents. Algae can be classified into two main groups; first one is the microalgae, which includes blue green algae, dinoflagellates, bacillariophyta (diatoms)… etc., and second one is macroalgae (seaweeds) which includes green, brown and red algae. The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Moreover, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. Red algae are considered as the most important source of many biologically active metabolites in comparison to other algal classes. Seaweeds are used for great number of application by man. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry.

  2. [Diversity of associated nitrogen-fixing bacteria isolated from the pioneer plants-Vetiver zizanioides].

    Science.gov (United States)

    Zhao, Xianwei; Javed, Chaudhary Hassan; He, Yumei; Zhang, Zhiying; Peng, Guixiang; Tan, Zhiyuan

    2009-11-01

    Vetiver zizanioides is a perennial grass of the Poaceae family, known of its silage, soil and water conservation role. The aim of the study was to collect and identify the resources of the nitrogen-fixing bacteria associated with Vetiver zizanioides. Associated nitrogen-fixing bacteria isolated from Vetiver zizanioides were studied by SDS-PAGE whole-cell protein patterns, insert sequence (IS)-PCR finger printing, utilization of sole carbon sources and 16S rRNA gene sequence analysis. Based on the results of finger printing analysis, protein patterns and biological test, isolates were grouped into 6 clusters, except 4 single strains. Phylogenetic analysis of 16S rDNA sequences indicated that isolates belonged to Herbaspirillum frisingense, Enterobacter ludwigii, Pseudacidovorax intermedius, Mitsuaria chitosanitabida, Pseudomonas putida, Pseudomonas fluorescens, Burkholderia vietnamiensis and Enterobacter cloacae. The nitrogen fixers associated with Vetiver zizanioides showed great diversity and may have a potential application for the grass forage and agriculture.

  3. Evaluation of nutrient limitation in aquatic ecosystems with nitrogen fixing bacteria

    Institute of Scientific and Technical Information of China (English)

    WU Gen-fu; WU Xue-chang; XUAN Xiao-dong; ZHOU Xue-ping

    2006-01-01

    There has always been a great need for simple and accurate bioassays for evaluating nutrient limitation in aquatic ecosystems. Whereas organic carbon is usually considered to be the limiting nutrient for microbial growth in many aquatic ecosystems,there are, however, many water sources that are limited by phosphorus or nitrogen. A method named "nitrogen fixing bacterial growth potential" (NFBGP) test, which is based on pre-culturing ofautochthonous (target) microorganisms was described. The method was applied to evaluate phosphorus or nitrogen nutrient limitation in lake and sewage water samples using an isolate of the nitrogen fixing bacterium, Azorhizobium sp. WS6. The results corresponded well to those from the traditional algal growth potential (AGP) test and the bacterial regrowth potential (BRP) test, suggesting that the NFBGP test is a useful supplementary method for evaluating the limiting nutrient, especially phosphorus, in an aquatic environment.

  4. Identification of Nitrogen-Fixing Genes and Gene Clusters from Metagenomic Library of Acid Mine Drainage

    OpenAIRE

    Zhimin Dai; Xue Guo; Huaqun Yin; Yili Liang; Jing Cong; Xueduan Liu

    2014-01-01

    Biological nitrogen fixation is an essential function of acid mine drainage (AMD) microbial communities. However, most acidophiles in AMD environments are uncultured microorganisms and little is known about the diversity of nitrogen-fixing genes and structure of nif gene cluster in AMD microbial communities. In this study, we used metagenomic sequencing to isolate nif genes in the AMD microbial community from Dexing Copper Mine, China. Meanwhile, a metagenome microarray containing 7,776 large...

  5. Whole-Genome Sequence of the Nitrogen-Fixing Symbiotic Rhizobium Mesorhizobium loti Strain TONO

    Science.gov (United States)

    Hirakawa, Hideki; Sato, Shusei; Saeki, Kazuhiko; Hayashi, Makoto

    2016-01-01

    Mesorhizobium loti is the nitrogen-fixing microsymbiont for legumes of the genus Lotus. Here, we report the whole-genome sequence of a Mesorhizobium loti strain, TONO, which is used as a symbiont for the model legume Lotus japonicus. The whole-genome sequence of the strain TONO will be a solid platform for comparative genomics analyses and for the identification of genes responsible for the symbiotic properties of Mesorhizobium species.

  6. Fate of nitrogen-fixing bacteria in crude oil contaminated wetland ultisol.

    Science.gov (United States)

    John, R C; Itah, A Y; Essien, J P; Ikpe, D I

    2011-09-01

    The effect of crude oil on the growth of legumes (Calopogonium muconoides and Centrosema pubescens) and fate of nitrogen-fixing bacteria in wetland ultisol was investigated using standard cultural techniques. The results revealed observable effects of oil on soil physico-chemistry, plant growth and nodulation as well as on densities of heterotrophic, hydrocarbonoclastic and nitrogen fixing bacteria. The effects however varied with different levels (0.5%, 1%, 5%, 10%, 15% and 20%) of pollution. Ammonium and nitrate levels were high in the unpolluted soil but decreased with increase in pollution levels. Nitrite was not detected in contaminated soil probably due to the reduction in numbers of nitrogen fixers, from 5.26 ± 0.23 × l0(6)cfu/g in unpolluted soil to 9.0 ± 0.12 × 10(5) and 2.2 ± 0.08 × l0(5) cfu/g in soils with 5% and 20% levels of pollution respectively. The contaminated soil also exhibited gross reduction in the nodulation of legumes. A range of 13-57 nodules was observed in legumes from polluted soil against 476 nodules recorded for plants cultured on unpolluted soil. The heterogeneity of the microbial loads between oil-polluted and unpolluted soil were statistically significant (p bacteria (r = 0.91) and that of hydrocarbon utilizing bacteria (r = 0.86). On the other hand, relationships between the densities of nitrogen fixing bacteria and total hydrocarbons content was negative (r = -0.30) while positive relationships were recorded between the densities of different microbial groups and treatment periods except at 15% and 20% pollution levels. The LSD tests revealed highly significant differences (p nitrogen-fixing bacteria and total loss of soil fertility attributable to petroleum hydrocarbon contamination in the Niger Delta ultisol.

  7. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  8. Effect of vegetation types on soil arbuscular mycorrhizal fungi and nitrogen-fixing bacterial communities in a karst region.

    Science.gov (United States)

    Liang, Yueming; Pan, Fujing; He, Xunyang; Chen, Xiangbi; Su, Yirong

    2016-09-01

    Arbuscular mycorrhizal (AM) fungi and nitrogen-fixing bacteria play important roles in plant growth and recovery in degraded ecosystems. The desertification in karst regions has become more severe in recent decades. Evaluation of the fungal and bacterial diversity of such regions during vegetation restoration is required for effective protection and restoration in these regions. Therefore, we analyzed relationships among AM fungi and nitrogen-fixing bacteria abundances, plant species diversity, and soil properties in four typical ecosystems of vegetation restoration (tussock (TK), shrub (SB), secondary forest (SF), and primary forest (PF)) in a karst region of southwest China. Abundance of AM fungi and nitrogen-fixing bacteria, plant species diversity, and soil nutrient levels increased from the tussock to the primary forest. The AM fungus, nitrogen-fixing bacterium, and plant community composition differed significantly between vegetation types (p fungi and nitrogen-fixing bacteria, respectively. Available phosphorus, total nitrogen, and soil organic carbon levels and plant richness were positively correlated with the abundance of AM fungi and nitrogen-fixing bacteria (p fungi and nitrogen-fixing bacteria increased from the tussock to the primary forest and highlight the essentiality of these communities for vegetation restoration.

  9. Genomic identification of nitrogen-fixing Klebsiella variicola, K. pneumoniae and K. quasipneumoniae.

    Science.gov (United States)

    Chen, Mingyue; Li, Yuanyuan; Li, Shuying; Tang, Lie; Zheng, Jingwu; An, Qianli

    2016-01-01

    It was difficult to differentiate Klebsiella pneumoniae, K. quasipneumoniae and K. variicola by biochemical and phenotypic tests. Genomics increase the resolution and credibility of taxonomy for closely-related species. Here, we obtained the complete genome sequence of the K. variicola type strain DSM 15968(T) (=F2R9(T)). The genome of the type strain is a circular chromosome of 5,521,203 bp with 57.56% GC content. From 540 Klebsiella strains whose genomes had been publicly available as at 3 March 2015, we identified 21 strains belonging to K. variicola and 8 strains belonging to K. quasipneumoniae based on the genome average nucleotide identities (ANI). All the K. variicola strains, one K. pneumoniae strain and five K. quasipneumoniae strains contained nitrogen-fixing genes. A phylogenomic analysis showed clear species demarcations for these nitrogen-fixing bacteria. In accordance with the key biochemical characteristics of K. variicola, the idnO gene encoding 5-keto-D-gluconate 5-reductase for utilization of 5-keto-D-gluconate and the sorCDFBAME operon for catabolism of L-sorbose were present whereas the rbtRDKT operon for catabolism of adonitol was absent in the genomes of K. variicola strains. Therefore, the genomic analyses supported the ANI-based species delineation; the genome sequence of the K. variicola type strain provides the reference genome for genomic identification of K. variicola, which is a nitrogen-fixing species.

  10. Investigating the effects of metals on phenol oxidase-producing nitrogen-fixing Azotobacter chroococcum.

    Science.gov (United States)

    Herter, Susanne; Schmidt, Marlen; Thompson, Mark L; Mikolasch, Annett; Schauer, Frieder

    2013-06-01

    Expression of phenol oxidases (PO) in bacteria is often observed during physiological and morphological changes; in the nitrogen-fixing strain Azotobacter chroococcum SBUG 1484, it is accompanied by the formation of encysted cells and melanin. Herein, we studied the effects of copper and the depletion of the nitrogenase-relevant metals molybdenum and iron on physiological characteristics such as culture pigmentation, release of ortho-dihydroxylated melanin precursors, and expression of PO activity in A. chroococcum. Biomass production and melanogenic appearance were directly affected by the depletion of either iron or molybdenum, or in the absence of both metals. Only nitrogen-fixing cells growing in the presence of both metals and cultures supplemented with iron (molybdenum starved) showed the ability to produce an intensively brown-black melanin pigment typically associated with A. chroococcum. Accordingly, PO production was only detected in the presence of both metals and in iron-supplemented cultures starved of molybdenum. The total amount of catecholate siderophores produced by nitrogen-fixing melanogenic cells was considerably higher than in cultures starved of metal ions. Induction of enhanced PO activity was stimulated by additional copper sulfate, possibly related to cellular processes involved in the detoxification of this particular metal, and revealed distinct release of the ortho-dihydroxylated melanin precursors catechol and 3,4-dihydroxybenzoic acid.

  11. Starting points in plant-bacteria nitrogen-fixing symbioses: intercellular invasion of the roots.

    Science.gov (United States)

    Ibáñez, Fernando; Wall, Luis; Fabra, Adriana

    2017-04-01

    Agricultural practices contribute to climate change by releasing greenhouse gases such as nitrous oxide that are mainly derived from nitrogen fertilizers. Therefore, understanding biological nitrogen fixation in farming systems is beneficial to agriculture and environmental preservation. In this context, a better grasp of nitrogen-fixing systems and nitrogen-fixing bacteria-plant associations will contribute to the optimization of these biological processes. Legumes and actinorhizal plants can engage in a symbiotic interaction with nitrogen-fixing rhizobia or actinomycetes, resulting in the formation of specialized root nodules. The legume-rhizobia interaction is mediated by a complex molecular signal exchange, where recognition of different bacterial determinants activates the nodulation program in the plant. To invade plants roots, bacteria follow different routes, which are determined by the host plant. Entrance via root hairs is probably the best understood. Alternatively, entry via intercellular invasion has been observed in many legumes. Although there are common features shared by intercellular infection mechanisms, differences are observed in the site of root invasion and bacterial spread on the cortex reaching and infecting a susceptible cell to form a nodule. This review focuses on intercellular bacterial invasion of roots observed in the Fabaceae and considers, within an evolutionary context, the different variants, distribution and molecular determinants involved. Intercellular invasion of actinorhizal plants and Parasponia is also discussed. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Identification of symbiotic nitrogen-fixing bacteria from three African leguminous trees in Gorongosa National Park.

    Science.gov (United States)

    Teixeira, Helena; Rodríguez-Echeverría, Susana

    2016-07-01

    The symbiosis between leguminous plants and symbiotic nitrogen-fixing bacteria is a key component of terrestrial ecosystems. Woody legumes are well represented in tropical African forests but despite their ecological and socio-economic importance, they have been little studied for this symbiosis. In this study, we examined the identity and diversity of symbiotic-nitrogen fixing bacteria associated with Acacia xanthophloea, Faidherbia albida and Albizia versicolor in the Gorongosa National Park (GNP) in Mozambique. To the best of our knowledge, this is the first report on the identity of symbiotic-nitrogen fixing bacteria in this region. 166 isolates were obtained and subjected to molecular identification. BOX-A1R PCR was used to discriminate different bacterial isolates and PCR-sequencing of 16S rDNA, and two housekeeping genes, glnII and recA, was used to identify the obtained bacteria. The gene nifH was also analyzed to assess the symbiotic capacity of the obtained bacteria. All isolates from F. albida and Al. versicolor belonged to the Bradyrhizobium genus whereas isolates from Ac. xanthophloea clustered with Mesorhizobium, Rhizobium or Ensifer strains. Soil chemical analysis revealed significant differences between the soils occupied by the three studied species. Thus, we found a clear delimitation in the rhizobial communities and soils associated with Ac. xanthophloea, F. albida and Al. versicolor, and higher rhizobial diversity for Ac. xanthophloea than previously reported.

  13. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

    OpenAIRE

    Reinhardt,Érica. L.; Ramos,Patrícia L.; Manfio, Gilson P; Barbosa,Heloiza R.; Pavan, Crodowaldo; Moreira-Filho, Carlos A

    2008-01-01

    Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD anal...

  14. Plant Growth-Promoting Nitrogen-Fixing Enterobacteria Are in Association with Sugarcane Plants Growing in Guangxi, China

    OpenAIRE

    2012-01-01

    The current nitrogen fertilization for sugarcane production in Guangxi, the major sugarcane-producing area in China, is very high. We aim to reduce nitrogen fertilization and improve sugarcane production in Guangxi with the help of indigenous sugarcane-associated nitrogen-fixing bacteria. We initially obtained 196 fast-growing bacterial isolates associated with the main sugarcane cultivar ROC22 plants in fields using a nitrogen-deficient minimal medium and screened out 43 nitrogen-fixing isol...

  15. Large-scale phylogenetic analyses reveal multiple gains of actinorhizal nitrogen-fixing symbioses in angiosperms associated with climate change.

    Science.gov (United States)

    Li, Hong-Lei; Wang, Wei; Mortimer, Peter E; Li, Rui-Qi; Li, De-Zhu; Hyde, Kevin D; Xu, Jian-Chu; Soltis, Douglas E; Chen, Zhi-Duan

    2015-09-10

    Nitrogen is fundamental to all life forms and is also one of the most limiting of nutrients for plant growth. Several clades of angiosperms have developed symbiotic relationships with actinorhizal bacteria that fix atmospheric nitrogen and increase access to this nutrient. However, the evolutionary patterns of actinorhizal nitrogen-fixing symbioses remain unclear to date. Furthermore the underlying environmental pressures that led to the gain of symbiotic actinorhizal nitrogen fixation have never been investigated. Here, we present the most comprehensive genus-level phylogenetic analysis of the nitrogen-fixing angiosperms based on three plastid loci. We found that actinorhizal nitrogen-fixing species are distributed in nine distinct lineages. By dating the branching events, we determined that seven actinorhizal nitrogen-fixing lineages originated during the Late Cretaceous, and two more emerged during the Eocene. We put forward a hypothesis that multiple gains of actinorhizal nitrogen-fixing symbioses in angiosperms may have been associated with increased global temperatures and high levels of atmospheric carbon dioxide during these two time periods, as well as the availability of open habitats with high light conditions. Our nearly complete genus-level time-tree for the nitrogen-fixing clade is a significant advance in understanding the evolutionary and ecological background of this important symbiosis between plants and bacteria.

  16. Cowpea symbiotic efficiency, pH and aluminum tolerance in nitrogen-fixing bacteria

    Directory of Open Access Journals (Sweden)

    Bruno Lima Soares

    2014-06-01

    Full Text Available Cowpea (Vigna unguiculata cultivation in northern and northeastern Brazil provides an excellent source of nutrients and carbohydrates for the poor and underprivileged. Production surplus leads to its consumption in other regions of Brazil and also as an export commodity. Its capacity to establish relationships with atmospheric nitrogen-fixing bacteria is crucial to the reduction of production costs and the environmental impact of nitrogen fertilizers. This study assessed the symbiotic efficiency of new strains of symbiotic nitrogen-fixing bacteria with cowpea and their tolerance to pH and aluminum. Twenty-seven strains of bacteria from different soils were evaluated under axenic conditions. These strains were compared to the following inoculant strains: INPA03-11B, UFLA03-84 and BR3267 and two controls that were not inoculated (with and without mineral nitrogen. Six strains and the three strains approved as inoculants were selected to increase the dry weight production of the aerial part (DWAP and were tested in pots with soil that had a high-density of nitrogen-fixing native rhizobia. In this experiment, three strains (UFLA03-164, UFLA03-153, and UFLA03-154 yielded higher DWAP values. These strains grow at pH levels of 5.0, 6.0, 6.8 and at high aluminum concentration levels, reaching 10(9 CFU mL-1. In particular UFLA03-84, UFLA03-153, and UFLA03-164 tolerate up to 20 mmol c dm-3 of Al+3. Inoculation with rhizobial strains, that had been carefully selected according to their ability to nodulate and fix N2, combined with their ability to compete in soils that are acidic and contain high levels of Al, is a cheaper and more sustainable alternative that can be made available to farmers than mineral fertilizers.

  17. Biofilm formation enables free-living nitrogen-fixing rhizobacteria to fix nitrogen under aerobic conditions.

    Science.gov (United States)

    Wang, Di; Xu, Anming; Elmerich, Claudine; Ma, Luyan Z

    2017-07-01

    The multicellular communities of microorganisms known as biofilms are of high significance in agricultural setting, yet it is largely unknown about the biofilm formed by nitrogen-fixing bacteria. Here we report the biofilm formation by Pseudomonas stutzeri A1501, a free-living rhizospheric bacterium, capable of fixing nitrogen under microaerobic and nitrogen-limiting conditions. P. stutzeri A1501 tended to form biofilm in minimal media, especially under nitrogen depletion condition. Under such growth condition, the biofilms formed at the air-liquid interface (termed as pellicles) and the colony biofilms on agar plates exhibited nitrogenase activity in air. The two kinds of biofilms both contained large ovoid shape 'cells' that were multiple living bacteria embedded in a sac of extracellular polymeric substances (EPSs). We proposed to name such large 'cells' as A1501 cyst. Our results suggest that the EPS, especially exopolysaccharides enabled the encased bacteria to fix nitrogen while grown under aerobic condition. The formation of A1501 cysts was reversible in response to the changes of carbon or nitrogen source status. A1501 cyst formation depended on nitrogen-limiting signaling and the presence of sufficient carbon sources, yet was independent of an active nitrogenase. The pellicles formed by Azospirillum brasilense, another free-living nitrogen-fixing rhizobacterium, which also exhibited nitrogenase activity and contained the large EPS-encapsuled A1501 cyst-like 'cells'. Our data imply that free-living nitrogen-fixing bacteria could convert the easy-used carbon sources to exopolysaccharides in order to enable nitrogen fixation in a natural aerobic environment.

  18. [SCREENING AND SELECTION OF THE SOIL MICROORGANISMS ON THE ABILITY OF "NITROGEN-FIXING ACTIVITY"].

    Science.gov (United States)

    Patyka V Ph; Kyrychenko, O V; Kots, S Ya

    2015-01-01

    The isolates of microorganisms from the rhizosphere of spring barley plants and soil at the use of analytical selection method was isolated. Its isolates on the ability of "nitrogen-fixing activity" was tested. It was shown that isolates of microorganisms had different of the colonies formed and cultural growth on the Eshbi's selective medium as well as the ability to fixing of molecular nitrogen. The different levels of intensity and dynamics of isolates nitrogenase activity in vitro were identified. New isolates of the soil microorganisms complement of the gene pool diazotrophic bacteria. Its isolates are perspectivity for the study as the basis or components of the bacterial fertilizers for the crops.

  19. Isoptopic evidence of the transfer of nitrogen fixed by legumes to coffee trees

    Directory of Open Access Journals (Sweden)

    Snoeck D.

    2000-01-01

    Full Text Available The use of isotopic methods has made it possible to quantify the contribution of nitrogen fixed by a coffee plantation. Thanks to the use of the natural 15N abundance assessment technique, we were able to show that, in field condition, roughly 30/ of the nitrogen effectively fixed by a legume (including biomass, roots and root exudates were transferred to the associated coffee trees. The quantities of N transferred by legume prunings to sole coffee trees were measured to evaluate the amount of N transferred to coffee via litter fall or soil.

  20. Novel metabolic attributes of the genus cyanothece, comprising a group of unicellular nitrogen-fixing Cyanothece.

    Science.gov (United States)

    Bandyopadhyay, Anindita; Elvitigala, Thanura; Welsh, Eric; Stöckel, Jana; Liberton, Michelle; Min, Hongtao; Sherman, Louis A; Pakrasi, Himadri B

    2011-01-01

    The genus Cyanothece comprises unicellular cyanobacteria that are morphologically diverse and ecologically versatile. Studies over the last decade have established members of this genus to be important components of the marine ecosystem, contributing significantly to the nitrogen and carbon cycle. System-level studies of Cyanothece sp. ATCC 51142, a prototypic member of this group, revealed many interesting metabolic attributes. To identify the metabolic traits that define this class of cyanobacteria, five additional Cyanothece strains were sequenced to completion. The presence of a large, contiguous nitrogenase gene cluster and the ability to carry out aerobic nitrogen fixation distinguish Cyanothece as a genus of unicellular, aerobic nitrogen-fixing cyanobacteria. Cyanothece cells can create an anoxic intracellular environment at night, allowing oxygen-sensitive processes to take place in these oxygenic organisms. Large carbohydrate reserves accumulate in the cells during the day, ensuring sufficient energy for the processes that require the anoxic phase of the cells. Our study indicates that this genus maintains a plastic genome, incorporating new metabolic capabilities while simultaneously retaining archaic metabolic traits, a unique combination which provides the flexibility to adapt to various ecological and environmental conditions. Rearrangement of the nitrogenase cluster in Cyanothece sp. strain 7425 and the concomitant loss of its aerobic nitrogen-fixing ability suggest that a similar mechanism might have been at play in cyanobacterial strains that eventually lost their nitrogen-fixing ability. The unicellular cyanobacterial genus Cyanothece has significant roles in the nitrogen cycle in aquatic and terrestrial environments. Cyanothece sp. ATCC 51142 was extensively studied over the last decade and has emerged as an important model photosynthetic microbe for bioenergy production. To expand our understanding of the distinctive metabolic capabilities of

  1. RESISTANCE OF KARST CAVERNS NITROGEN-FIXING BACTERIA TO EXTREME FACTORS

    Directory of Open Access Journals (Sweden)

    Tashyrev O. B.

    2014-10-01

    Full Text Available To determine the studied bacteria resistance quantitative parameters of extreme factors such as toxic metals (Cu2+, organic xenobiotics (p-nitrochlorobenzene and UV-irradiation were the aim of the research. Six strains of nitrogen-fixing bacteria isolated from clays of two caverns Mushkarova Yama (Podolia, Ukraine and Kuybyshevskaya (Western Caucasus, Abkhazia and Azotobacter vinelandii УКМ В-6017 as a reference strain have been tested. For this purpose the maximum permissible concentration of Cu2+ and p-nitrochlorobenzene in the concentration gradient and lethal doses of UV by the survival caverns have been determined. Maximum permissible concentrations for strains were as 10 ppm Cu2+, 70–120 ppm of p-nitrochlorobenzene. The maximum doses of UV-irradiation varied in the range of 55–85 J/m2 (LD99.99. It is shown that three classes of extreme factors resistance parameters of karst caverns strains are similar to the strain of terrestrial soil ecosystems. The most active studied strains reduce the concentration of p-nitrochlorobenzene in the medium in 13 times. The ability of nitrogen-fixing bacteria to degrade p-nitrochlorobenzene could be used in creation new environmental biotechnology for industrial wastewater treatment from nitrochloroaromatic xenobiotics. Isolated strains could be used as destructors for soils bioremediation in agrobiotechnologies and to optimize plants nitrogen nutrition in terrestrial ecosystems.

  2. Identification of nitrogen-fixing genes and gene clusters from metagenomic library of acid mine drainage.

    Science.gov (United States)

    Dai, Zhimin; Guo, Xue; Yin, Huaqun; Liang, Yili; Cong, Jing; Liu, Xueduan

    2014-01-01

    Biological nitrogen fixation is an essential function of acid mine drainage (AMD) microbial communities. However, most acidophiles in AMD environments are uncultured microorganisms and little is known about the diversity of nitrogen-fixing genes and structure of nif gene cluster in AMD microbial communities. In this study, we used metagenomic sequencing to isolate nif genes in the AMD microbial community from Dexing Copper Mine, China. Meanwhile, a metagenome microarray containing 7,776 large-insertion fosmids was constructed to screen novel nif gene clusters. Metagenomic analyses revealed that 742 sequences were identified as nif genes including structural subunit genes nifH, nifD, nifK and various additional genes. The AMD community is massively dominated by the genus Acidithiobacillus. However, the phylogenetic diversity of nitrogen-fixing microorganisms is much higher than previously thought in the AMD community. Furthermore, a 32.5-kb genomic sequence harboring nif, fix and associated genes was screened by metagenome microarray. Comparative genome analysis indicated that most nif genes in this cluster are most similar to those of Herbaspirillum seropedicae, but the organization of the nif gene cluster had significant differences from H. seropedicae. Sequence analysis and reverse transcription PCR also suggested that distinct transcription units of nif genes exist in this gene cluster. nifQ gene falls into the same transcription unit with fixABCX genes, which have not been reported in other diazotrophs before. All of these results indicated that more novel diazotrophs survive in the AMD community.

  3. [Diversity of nitrogen-fixing microorganisms in biological soil crusts of copper mine wastelands].

    Science.gov (United States)

    Zhan, Jing; Yang, Gui-De; Sun, Qing-Ye

    2014-06-01

    Biological soil crusts play an important role in increasing the accumulation of organic matter and nitrogen in re-vegetated mining wastelands. The diversity of nitrogen-fixing microorganisms in three types of biological soil crusts (algal crust, moss crust and algal-moss crust) from two wastelands of copper mine tailings were investigated by polymerase chain reaction-denaturing gradient gel electrophoresis, based on the nifH gene of diazotrophs, to investigate: The diversity of nifH gene in the crusts of mine wastelands, and whether and how the nifH gene diversity in the crusts could be affected by the development of plant communities. The algal crust on the barren area displayed the highest nifH gene diversity, followed by the algal-moss crusts within vascular plant communities, and the moss crust displayed the lowest nifH gene diversity. The diversity of diazotrophs in algal-moss crust within vascular plant communities decreased with the increase of height and cover of vascular plant communities. No significant relationship was found between wasteland properties (pH, water content, contents of organic matter, nitrogen and phosphorus and heavy metal concentration) and nifH gene diversity in the crusts. Sequencing and phylogenetic analysis indicated that most nitrogen-fixing taxa in the crusts of mine wastelands belonged to Cyanobacteria, especially nonheterocystous filamentous Cyanobacteria.

  4. Identification of nitrogen-fixing genes and gene clusters from metagenomic library of acid mine drainage.

    Directory of Open Access Journals (Sweden)

    Zhimin Dai

    Full Text Available Biological nitrogen fixation is an essential function of acid mine drainage (AMD microbial communities. However, most acidophiles in AMD environments are uncultured microorganisms and little is known about the diversity of nitrogen-fixing genes and structure of nif gene cluster in AMD microbial communities. In this study, we used metagenomic sequencing to isolate nif genes in the AMD microbial community from Dexing Copper Mine, China. Meanwhile, a metagenome microarray containing 7,776 large-insertion fosmids was constructed to screen novel nif gene clusters. Metagenomic analyses revealed that 742 sequences were identified as nif genes including structural subunit genes nifH, nifD, nifK and various additional genes. The AMD community is massively dominated by the genus Acidithiobacillus. However, the phylogenetic diversity of nitrogen-fixing microorganisms is much higher than previously thought in the AMD community. Furthermore, a 32.5-kb genomic sequence harboring nif, fix and associated genes was screened by metagenome microarray. Comparative genome analysis indicated that most nif genes in this cluster are most similar to those of Herbaspirillum seropedicae, but the organization of the nif gene cluster had significant differences from H. seropedicae. Sequence analysis and reverse transcription PCR also suggested that distinct transcription units of nif genes exist in this gene cluster. nifQ gene falls into the same transcription unit with fixABCX genes, which have not been reported in other diazotrophs before. All of these results indicated that more novel diazotrophs survive in the AMD community.

  5. Nitrogen fixing bacteria in the family Acetobacteraceae and their role in agriculture.

    Science.gov (United States)

    Reis, Veronica Massena; Teixeira, Kátia Regina dos Santos

    2015-08-01

    For centuries, the Acetobacteraceae is known as a family that harbors many species of organisms of biotechnological importance for industry. Nonetheless, since 1988 representatives of this family have also been described as nitrogen fixing bacteria able to plant growth promotion by a variety of mechanisms. Nitrogen fixation is a biological process that guarantees that the atmospheric N2 is incorporated into organic matter by several bacterial groups. Most representatives of this group, also known as diazotrophic, are generally associated with soil rhizosphere of many plants and also establishing a more specific association living inside roots, leaves, and others plants tissues as endophyte. Their roles as plant growth-promoting microorganisms are generally related to increase in plant biomass, phosphate and other mineral solubilization, and plant pathogen control. Here, we report many of these plant growth-promoting processes related to nitrogen fixing species already described in Acetobacteraceae family, especially Gluconacetobacter diazotrophicus and their importance to agriculture. In addition, a brief review of the state of art of the phylogenetics, main physiological and biochemical characteristics, molecular and functional genomic data of this group of Acetobacteraceae is presented.

  6. Physico-chemical properties of polyhydroxyalkanoate produced by mixed-culture nitrogen-fixing bacteria.

    Science.gov (United States)

    Patel, Meeta; Gapes, Daniel J; Newman, Roger H; Dare, Peter H

    2009-03-01

    Ultra-high molecular weight polyhydroxyalkanoates (PHAs) with low polydispersity index (PDI = 1.3) were produced in a novel, pilot scale application of mixed cultures of nitrogen-fixing bacteria. The number average molecular weight (M (n)) of the poly(3-hydroxybutyrate) (P(3HB)) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) was determined to be 2.4 x 10(6) and 2.5 x 10(6) g mol(-1), respectively. Using two types of carbon sources, biomass contents of the P(3HB) and P(3HB-co-3HV) were 18% and 30% (PHA in dry biomass), respectively. The extracted polymers were analysed for their physical properties using analytical techniques such as nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). NMR confirmed the formation of homopolymer and copolymer. DSC showed a single melting endotherm peak for both polymers, with enthalpies that indicated crystallinity indices of 44% and 37% for P(3HB) and P(3HB-co-3HV), respectively. GPC showed a sharp unimodal trace for both polymers, reflecting the homogeneity of the polymer chains. The work described here emphasises the potential of mixed colony nitrogen-fixing bacteria cultures for producing biodegradable polymers which have properties that are very similar to those from their pure-culture counterparts and therefore making a more economically viable route for obtaining biopolyesters.

  7. Microscopic origin of the fast blue-green luminescence of chemically synthesized non-oxidized silicon quantum dots

    NARCIS (Netherlands)

    Dohnalová, K.; Fučiková, A.; Umesh, C.P.; Humpoličková, J.; Paulusse, J.M.J.; Valenta, J.; Zuilhof, H.; Hof, M.; Gregorkiewicz, T.

    2012-01-01

    The microscopic origin of the bright nanosecond blue-green photoluminescence (PL), frequently reported for synthesized organically terminated Si quantum dots (Si-QDs), has not been fully resolved, hampering potential applications of this interesting material. Here a comprehensive study of the PL

  8. Microscopic Origin of the Fast Blue-Green Luminescence from Chemically Synthesized Non-Oxidized Silicon Quantum Dots

    NARCIS (Netherlands)

    Dohnalová, K.; Gregorkiewicz, T.; Fucíková, A.; Valenta, J.; Umesh, C.; Paulusse, J.M.J.; Zuilhof, H.; Humpolícková, J.; Hof, van M.

    2012-01-01

    The microscopic origin of the bright nanosecond blue-green photoluminescence (PL), frequently reported for synthesized organically terminated Si quantum dots (Si-QDs), has not been fully resolved, hampering potential applications of this interesting material. Here a comprehensive study of the PL

  9. Deep 16sRNA sequencing of anterior foregut microbiota from the blue-green sharpshooter (Graphocephala atropunctata)

    Science.gov (United States)

    Graphocephala atropunctata (Signoret) (Hemiptera: Cicadellidae) or the blue-green sharpshooter (BGSS) has been long recognized as the principal native vector of Xylella fastidiosa in coastal, wine-grape growing areas of California. X. fastidiosa is the causative agent of Pierce’s disease of grapevin...

  10. A designer ligand field for blue-green luminescence of organoeuropium(ii) sandwich complexes with cyclononatetraenyl ligands.

    Science.gov (United States)

    Kawasaki, Kenshiro; Sugiyama, Rion; Tsuji, Takashi; Iwasa, Takeshi; Tsunoyama, Hironori; Mizuhata, Yoshiyuki; Tokitoh, Norihiro; Nakajima, Atsushi

    2017-06-21

    A novel η(9)-coordinated double-decker sandwich complex of divalent europium is synthesized. The complex exhibits blue-green photoluminescence at 516 nm, which is significantly blue-shifted from those of other organoeuropium(ii) sandwich complexes (∼630 nm). The blue-shift was quantitatively explained by the weakened electrostatic field of the expanded 10-π ring.

  11. Plant growth-promoting nitrogen-fixing enterobacteria are in association with sugarcane plants growing in Guangxi, China.

    Science.gov (United States)

    Lin, Li; Li, Zhengyi; Hu, Chunjin; Zhang, Xincheng; Chang, Siping; Yang, Litao; Li, Yangrui; An, Qianli

    2012-01-01

    The current nitrogen fertilization for sugarcane production in Guangxi, the major sugarcane-producing area in China, is very high. We aim to reduce nitrogen fertilization and improve sugarcane production in Guangxi with the help of indigenous sugarcane-associated nitrogen-fixing bacteria. We initially obtained 196 fast-growing bacterial isolates associated with the main sugarcane cultivar ROC22 plants in fields using a nitrogen-deficient minimal medium and screened out 43 nitrogen-fixing isolates. Analysis of 16S rRNA gene sequences revealed that 42 of the 43 nitrogen-fixing isolates were affiliated with the genera Enterobacter and Klebsiella. Most of the nitrogen-fixing enterobacteria possessed two other plant growth-promoting activities of IAA production, siderophore production and phosphate solubilization. Two Enterobacter spp. strains of NN145S and NN143E isolated from rhizosphere soil and surface-sterilized roots, respectively, of the same ROC22 plant were used to inoculate micropropagated sugarcane plantlets. Both strains increased the biomass and nitrogen content of the sugarcane seedlings grown with nitrogen fertilization equivalent to 180 kg urea ha(-1), the recommended nitrogen fertilization for ROC22 cane crops at the seedling stage. (15)N isotope dilution assays demonstrated that biological nitrogen fixation contributed to plant growth promotion. These results suggested that indigenous nitrogen-fixing enterobacteria have the potential to fix N(2) associated with sugarcane plants grown in fields in Guangxi and to improve sugarcane production.

  12. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state.

    Science.gov (United States)

    Reinhardt, Erica L; Ramos, Patrícia L; Manfio, Gilson P; Barbosa, Heloiza R; Pavan, Crodowaldo; Moreira-Filho, Carlos A

    2008-07-01

    Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data.

  13. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

    Science.gov (United States)

    Reinhardt, Érica. L.; Ramos, Patrícia L.; Manfio, Gilson P.; Barbosa, Heloiza R.; Pavan, Crodowaldo; Moreira-Filho, Carlos A.

    2008-01-01

    Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data. PMID:24031239

  14. Research Progress and Perspectives of Nitrogen Fixing Bacterium, Gluconacetobacter diazotrophicus, in Monocot Plants

    Directory of Open Access Journals (Sweden)

    N. Eskin

    2014-01-01

    Full Text Available Gluconacetobacter diazotrophicus is a nitrogen fixing bacterium originally found in monocotyledon sugarcane plants in which the bacterium actively fixes atmosphere nitrogen and provides significant amounts of nitrogen to plants. This bacterium mainly colonizes intercellular spaces within the roots and stems of plants and does not require the formation of the complex root organ like nodule. The bacterium is less plant/crop specific and indeed G. diazotrophicus has been found in a number of unrelated plant species. Importantly, as the bacterium was of monocot plant origin, there exists a possibility that the nitrogen fixation feature of the bacterium may be used in many other monocot crops. This paper reviews and updates the research progress of G. diazotrophicus for the past 25 years but focuses on the recent research development.

  15. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Science.gov (United States)

    Banerjee, Aulie; Supakar, Subhrangshu; Banerjee, Raja

    2014-01-01

    Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13)C NMR), we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  16. Characterization of nitrogen-fixing bacteria isolated from field-grown barley, oat, and wheat.

    Science.gov (United States)

    Venieraki, Anastasia; Dimou, Maria; Vezyri, Eleni; Kefalogianni, Io; Argyris, Nikolaos; Liara, Georgia; Pergalis, Panagiotis; Chatzipavlidis, Iordanis; Katinakis, Panagiotis

    2011-08-01

    Diazotrophic bacteria were isolated from the rhizosphere of field-grown Triticum aestivum, Hordeum vulgare, and Avena sativa grown in various regions of Greece. One isolate, with the highest nitrogen-fixation ability from each of the eleven rhizospheres, was selected for further characterisation. Diazotrophic strains were assessed for plant-growth-promoting traits such as indoleacetic acid production and phosphate solubilisation. The phylogenies of 16S rRNA gene of the selected isolates were compared with those based on dnaK and nifH genes. The constructed trees indicated that the isolates were members of the species Azospirillum brasilense, Azospirillum zeae, and Pseudomonas stutzeri. Furthermore, the ipdC gene was detected in all A. brasilence and one A. zeae isolates. The work presented here provides the first molecular genetic evidence for the presence of culturable nitrogen-fixing P. stutzeri and A. zeae associated with field-grown A. sativa and H. vulgare in Greece.

  17. The plant growth-promoting effect of the nitrogen-fixing endophyte Pseudomonas stutzeri A15.

    Science.gov (United States)

    Pham, Van T K; Rediers, Hans; Ghequire, Maarten G K; Nguyen, Hiep H; De Mot, René; Vanderleyden, Jos; Spaepen, Stijn

    2017-04-01

    The use of plant growth-promoting rhizobacteria as a sustainable alternative for chemical nitrogen fertilizers has been explored for many economically important crops. For one such strain isolated from rice rhizosphere and endosphere, nitrogen-fixing Pseudomonas stutzeri A15, unequivocal evidence of the plant growth-promoting effect and the potential contribution of biological nitrogen fixation (BNF) is still lacking. In this study, we investigated the effect of P. stutzeri A15 inoculation on the growth of rice seedlings in greenhouse conditions. P. stutzeri A15 induced significant growth promotion compared to uninoculated rice seedlings. Furthermore, inoculation with strain A15 performed significantly better than chemical nitrogen fertilization, clearly pointing to the potential of this bacterium as biofertilizer. To assess the contribution of BNF to the plant growth-promoting effect, rice seedlings were also inoculated with a nitrogen fixation-deficient mutant. Our results suggest that BNF (at best) only partially contributes to the stimulation of plant growth.

  18. [Electrooptical properties of soil nitrogen-fixing bacterium Azospirillum brasilense: effect of copper ions].

    Science.gov (United States)

    Ignatov, O V; Kamnev, A A; Markina, L N; Antoniuk, L P; Kolina, M; Ignatov, V V

    2001-01-01

    The effects of copper ions on the uptake of some essential metals in the biomass and the electrooptical properties of cell suspensions of the nitrogen-fixing soil bacterium Azospirillum brasilense sp. 245 were studied. Copper cations were shown to be effectively taken up by the cell biomass from the culture medium. The addition of copper ions increased the rate of uptake of some other metals present in the culture medium. This was accompanied by changes in the electrooptical characteristics of cell suspension as measured within the orienting electric field frequency range of 10 to 10,000 kHz. The effects observed during short-term incubation of A. brasilense in the presence of copper cations were less significant than during long-term incubation. These results can be used for rapid screening of microbial cultures for enhanced efficiency of sorption and uptake of metals.

  19. Seabird nutrient subsidies benefit non-nitrogen fixing trees and alter species composition in South American coastal dry forests.

    Directory of Open Access Journals (Sweden)

    Gilles Havik

    Full Text Available Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing species, increasing the relative abundance of non-nitrogen fixing species close to seashore. Moreover, we proposed that herbivores can alter the effects of nutrient supplementation by preferentially feeding on high nutrient plants. We studied the effects of nutrient fertilization by seabird guano on tree recruitment and how these effects can be modulated by herbivorous lizards in the coastal dry forests of northwestern Peru. We combined field studies, experiments and stable isotope analysis to study the response of the two most common tree species in these forests, the nitrogen-fixing Prosopis pallida and the non-nitrogen-fixing Capparis scabrida. We did not find differences in herbivore pressure along the sea-inland gradient. We found that the non-nitrogen fixing C. scabrida assimilates marine-derived nitrogen and is more abundant than P. pallida closer to guano-rich soil. We conclude that the input of marine-derived nitrogen through guano deposited by seabirds feeding in the Pacific Ocean affects the two dominant tree species of the coastal dry forests of northern Peru in contrasting ways. The non-nitrogen fixing species, C. scabrida may benefit from sea nutrient subsidies by incorporating guano-derived nitrogen into its foliar tissues, whereas P. pallida, capable of atmospheric fixation, does not.

  20. Paenibacillus jilunlii sp. nov., a nitrogen-fixing species isolated from the rhizosphere of Begonia semperflorens.

    Science.gov (United States)

    Jin, Hao-Jie; Zhou, Yu-Guang; Liu, Hong-Can; Chen, San-Feng

    2011-06-01

    A nitrogen-fixing bacterium, designated strain Be17(T), was isolated from rhizosphere soil of Begonia semperflorens planted in Beijing Botanical Garden, PR China. Phylogenetic analyses based on a segment of the nifH gene sequence and a full-length 16S rRNA gene sequence revealed that strain Be17(T) was a member of the genus Paenibacillus. High levels of 16S rRNA gene sequence similarity were found between strain Be17(T) and Paenibacillus graminis RSA19(T) (97.9 %), Paenibacillus sonchi LMG 24727(T) (97.8 %), Paenibacillus riograndensis CECT 7330(T) (96.2 %) and Paenibacillus borealis DSM 13188(T) (96.1 %), respectively. Levels of 16S rRNA gene sequence similarity between strain Be17(T) and the type strains of other recognized members of the genus Paenibacillus were below 96.0 %. However, the DNA-DNA hybridization values between strain Be17(T) and P. graminis RSA19(T), P. sonchi LMG 24727(T) and P. riograndensis CECT 7330(T) were 47.9 %, 38.7 % and 37.5 %, respectively. The DNA G+C content of strain Be17(T) was 52.9 mol%. The major fatty acid component of strain Be17(T) was anteiso-branched C(15 : 0) (30.92 %). The major isoprenoid quinone was MK-7. The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. On the basis of its phenotypic characteristics, 16S rRNA gene sequences, DNA G+C content, DNA-DNA relatedness, chemotaxonomic properties and nifH gene sequence, strain Be17(T) represents a nitrogen-fixing strain of a novel species of the genus Paenibacillus, for which the name Paenibacillus jilunlii sp. nov. is proposed. The type strain is Be17(T) ( = CGMCC 1.10239(T) = DSM 23019(T)).

  1. Response of the nitrogen-fixing lichen Lobaria pulmonaria to phosphorus, molybdenum, and vanadium

    Science.gov (United States)

    Marks, Jade A; Pett-Ridge, Julie; Perakis, Steven S.; Allen, Jessica L; McCune, Bruce

    2015-01-01

    Nitrogen-fixing lichens (cyanolichens) are an important source of nitrogen (N) in Pacific Northwest forests, but limitation of lichen growth by elements essential for N fixation is poorly understood. To investigate how nutrient limitation may affect cyanolichen growth rates, we fertilized a tripartite cyanobacterial lichen (Lobaria pulmonaria) and a green algal non-nitrogen fixing lichen (Usnea longissima) with the micronutrients molybdenum (Mo) and vanadium (V), both known cofactors for enzymes involved in N fixation, and the macronutrient phosphorus (P). We then grew treated lichens in the field for one year in western Oregon, USA. Lichen growth was very rapid for both species and did not differ across treatments, despite a previous demonstration of P-limitation in L. pulmonaria at a nearby location. To reconcile these disparate findings, we analyzed P, Mo, and V concentrations, natural abundance δ15N isotopes, %N and change in thallus N in Lobaria pulmonaria from both growth experiments. Nitrogen levels in deposition and in lichens could not explain the large difference in growth or P limitation observed between the two studies. Instead, we provide evidence that local differences in P availability may have caused site-specific responses of Lobaria to P fertilization. In the previous experiment, Lobaria had low background levels of P, and treatment with P more than doubled growth. In contrast, Lobaria from the current experiment had much higher background P concentrations, similar to P-treated lichens in the previous experiment, consistent with the idea that ambient variation in P availability influences the degree of P limitation in cyanolichens. We conclude that insufficient P, Mo, and V did not limit the growth of either cyanolichens or chlorolichens at the site of the current experiment. Our findings point to the need to understand landscape-scale variation in P availability to cyanolichens, and its effect on spatial patterns of cyanolichen nutrient

  2. Nitrogen-fixing aerobic bacteria have higher genomic GC content than non-fixing species within the same genus

    OpenAIRE

    McEwan, Catriona E.; Gatherer, Derek; McEwan, Neil R.

    1998-01-01

    The genomic GC contents of both nitrogen-fixing and non-fixing members of eight genera of bacteria are investigated. Analysis by t-tests showed that in the two aerobic genera investigated (Aquaspirillum and Vibrio) there is a significantly higher GC content in the nitrogen-fixing members of the genus than in those unable to Fix nitrogen, whilst in anaerobic genera there is either no GC bias, or in the case of two genera (Rhodospirillum and Clostridium) there is a significantly higher GC conte...

  3. Green roof and storm water management policies: monitoring experiments on the ENPC Blue Green Wave

    Science.gov (United States)

    Versini, Pierre-Antoine; Gires, Auguste; Fitton, George; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2015-04-01

    Currently widespread in new urban projects, green roofs have shown a positive impact on urban runoff at the building/parcel scale. Nevertheless, there is no specific policy promoting their implementation neither in Europe nor in France. Moreover they are not taken into account (and usually considered as an impervious area) in the sizing of a retention basin for instance. An interesting example is located in the heart of the Paris-East Cluster for Science and Technology (Champs-sur-Marne, France). Since 2013 a large (1 ha) wavy-form vegetated roof (called bleu green wave) is implemented. Green roof area and impervious areas are connected to a large retention basin, which has been oversized. The blue green wave represents a pioneering site where an initially amenity (decorative) design project has been transformed into a research oriented one. Several measurement campaigns have been conducted to investigate and better understand the hydrological behaviour of such a structure. Rainfall, humidity, wind velocity, water content and temperature have been particularly studied. The data collected are used for several purposes: (i) characterize the spatio-temporal variability of the green roof response, (ii) calibrate and validate a specific model simulating its hydrological behavior. Based on monitoring and modeling results, green roof performances will be quantified. It will be possible to estimate how they can reduce stormwater runoff and how these performances can vary in space and in time depending on green roof configuration, rainfall event characteristics and antecedent conditions. These quantified impacts will be related to regulation rules established by stormwater managers in order to connect the parcel to the sewer network. In the particular case of the building of a retention basin, the integration of green roof in the sizing of the basin will be studied. This work is funded by the European Blue Green Dream project (http://bgd.org.uk/, funded by Climate

  4. Dinosaur origin of egg color: oviraptors laid blue-green eggs

    Directory of Open Access Journals (Sweden)

    Jasmina Wiemann

    2017-08-01

    with our reconstruction of blue-green eggs for oviraptors. According to the sexual signaling hypothesis, the reconstructed blue-green eggs support the origin of previously hypothesized avian paternal care in oviraptorid dinosaurs. Preserved dinosaur egg color not only pushes the current limits of the vertebrate molecular and associated soft tissue fossil record, but also provides a perspective on the potential application of this unexplored paleontological resource.

  5. Comparison of the toxins of the blue-green alga Aphanizomenon flos-aquae with the Gonyaulax toxins.

    Science.gov (United States)

    Ikawa, M; Wegener, K; Foxall, T L; Sasner, J J

    1982-01-01

    A toxic strain of Aphanizomenon flos-aquae (NH-1), isolated from a toxic bloom in a pond in Durham, New Hampshire, has been mass cultured in the laboratory. The toxin was extracted by ultrasonic disruption of the cells and purified by; (a) filtration through a 10 kilodalton filter, and (b) chromatography on a strong cation exchange resin column using 0.01 M, then 0.1 M, pH 5, sodium acetate buffer followed by 0.75 M hydrochloric acid. Mouse assays and fluorescence generated by hydrogen peroxide oxidation were used to monitor the fractions. Only a nonfluorescent toxic peak followed immediately by a fluorescent less-toxic peak were detected, both eluting with the hydrochloric acid fractions. The toxins were identical in behavior to neosaxitoxin and saxitoxin, respectively, when compared with elution profiles of the paralytic shellfish poisons from Gonyaulax tamarensis var. excavata and by paper electrophoretic and thin-layer chromatographic comparisons. The toxin profile appears to be different from that of a previously isolated strain of A. flos-aquae from Kezar Lake.

  6. Nevada - the frontier of bio-geothermal conversion of blue-green algae, Spirulina, a high-protein food

    Energy Technology Data Exchange (ETDEWEB)

    Bedell, G.W.

    1983-08-01

    This article discusses the efforts that are underway to develop algal biomass production for both human and animal food, food supplements, other algally derived products, aquaculture of prawns and fish, and the production of new building materials derived from geothermal water that will be competitive with concrete. These projects are being mobilized to develop all aspects of Nevada geothermal and other hot water resources.

  7. Isolation and characterization of ultraviolet light-sensitive mutants of the blue-green alga Anacystis nidulans.

    Science.gov (United States)

    Asato, Y.

    1972-01-01

    Three independently isolated ultraviolet light sensitive (uvs) mutants of Anacystis nidulans were characterized. Strain uvs-1 showed the highest sensitivity to UV by its greatly reduced photoreactivation capacity following irradiation. Pretreatment with caffeine suppressed the dark-survival curve of strain uvs-1, thus indicating the presence of excision enzymes involved in dark repair. Under 'black' and 'white' illumination, strain uvs-1 shows photorecovery properties comparable with wild-type cultures. Results indicate that strains uvs-1, uvs-35, and uvs-88 are probably genetically distinct UV-sensitive mutants.

  8. On the occurrence of blooms of blue-green algae and the associated oceanographic conditions in the Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Jayaraman, R.

    the organism utilizes all the available nutrients from the environment, preventing the growth and proliferation of the more useful `producer' plankton such as diatoms and dinoflagellates An explanation has been attempted on the basis of "exclusion principle...

  9. Blue-Green solutions for improving water quality in an urbanizing catchment

    Science.gov (United States)

    Kalantari, Zahra; Sha, Bo; Ferreira, Carla Sofia; Sjöstedt, Carin

    2017-04-01

    With increasing urban population and expanding urban areas, cities have demonstrated great influences on natural resources and the surrounding environment. Urbanization process is generally accompanied by noticeable land use/cover change, such as turning permeable forest area and agricultural land into impervious landscapes like roads, parking lots, commercial and residential areas, leading to major environmental impacts on both the hydrological processes and water quality of the local catchment. Urban areas usually act as major diffuse pollution sources in a catchment. On the one hand, human activities increase the generation and accumulation of pollutants on urban surface; on the other hand, large impervious urban landscape improves the mobilization and transport of pollutants to receiving water body by increasing surface runoff and hydraulic efficiency. This study focuses on how different urbanization patterns would affect surface water quality, in order to examine whether the heterogeneity of urban areas would be an important factor that influencing surface water quality and what impacts it would induce. Furthermore, using coupled hydrological and water quality models, the effect of different blue green solutions including nature remnants and parks, gardens, small forests, wetlands and ponds; on improving the water quality will be investigated.

  10. The Efficacy of Blue-Green Infrastructure for Pluvial Flood Prevention under Conditions of Deep Uncertainty

    Science.gov (United States)

    Babovic, Filip; Mijic, Ana; Madani, Kaveh

    2017-04-01

    Urban areas around the world are growing in size and importance; however, cities experience elevated risks of pluvial flooding due to the prevalence of impermeable land surfaces within them. Urban planners and engineers encounter a great deal of uncertainty when planning adaptations to these flood risks, due to the interaction of multiple factors such as climate change and land use change. This leads to conditions of deep uncertainty. Blue-Green (BG) solutions utilise natural vegetation and processes to absorb and retain runoff while providing a host of other social, economic and environmental services. When utilised in conjunction with Decision Making under Deep Uncertainty (DMDU) methodologies, BG infrastructure provides a flexible and adaptable method of "no-regret" adaptation; resulting in a practical, economically efficient, and socially acceptable solution for flood risk mitigation. This work presents the methodology for analysing the impact of BG infrastructure in the context of the Adaptation Tipping Points approach to protect against pluvial flood risk in an iterative manner. An economic analysis of the adaptation pathways is also conducted in order to better inform decision-makers on the benefits and costs of the adaptation options presented. The methodology was applied to a case study in the Cranbrook Catchment in the North East of London. Our results show that BG infrastructure performs better under conditions of uncertainty than traditional grey infrastructure.

  11. Genome Sequence of Bradyrhizobium viridifuturi Strain SEMIA 690T, a Nitrogen-Fixing Symbiont of Centrosema pubescens

    Science.gov (United States)

    Helene, Luisa Caroline Ferraz; Gomes, Douglas Fabiano; Delamuta, Jakeline Renata Marçon; Ribeiro, Renan Augusto; Souza, Renata Carolini; Almeida, Luiz Gonzaga Paula; Vasconcelos, Ana Tereza Ribeiro

    2015-01-01

    SEMIA 690T is a nitrogen-fixing symbiont of Centrosema pubescens, and comprises the recently described species Bradyrhizobium viridifuturi. Its draft genome indicates that it belongs to the Bradyrhizobium elkanii superclade. SEMIA 690T carries two copies of the regulatory nodD gene, and the nod and nif operons resemble those of Bradyrhizobium diazoefficiens. PMID:26679590

  12. Effects of oxytetracycline on the abundance and community structure of nitrogen-fixing bacteria during cattle manure composting.

    Science.gov (United States)

    Sun, Jiajun; Qian, Xun; Gu, Jie; Wang, Xiaojuan; Gao, Hua

    2016-09-01

    The effects of oxytetracycline (OTC) on nitrogen-fixing bacterial communities were investigated during cattle manure composting. The abundance and community structure of nitrogen-fixing bacteria were determined by qPCR and denaturing gradient gel electrophoresis (DGGE), respectively. The matrix was spiked with OTC at four levels: no OTC, 10mg/kg dry weight (DW) OTC (L), 60mg/kg DW OTC (M), and 200mg/kg DW OTC (H). The high temperature period of composting was shorter with M and H, and the decline in temperature during the cooling stage was accelerated by OTC. OTC had a concentration-dependent inhibitory effect on the nitrogenase activity during early composting, and the nifH gene abundance declined significantly during the later composting stage. The DGGE profile and statistical analysis showed that OTC changed the nitrogen-fixing bacterial community succession and reduced the community richness and dominance. The nitrogen-fixing bacterial community structure was affected greatly by the high level of OTC.

  13. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Montaña, José Salvador; Martínez, María Mercedes

    2011-01-01

    With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB) of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-

  14. Novel expression pattern of cytosolic gln synthetase in nitrogen-fixing root nodules of the actinorhizal host, Datisca glomerata

    NARCIS (Netherlands)

    Berry, A.M.; Murphy, T.M.; Okubara, P.A.; Jacobsen, K.R.; Swensen, S.M.; Pawlowski, K.

    2004-01-01

    Gln synthetase (GS) is the key enzyme of primary ammonia assimilation in nitrogen-fixing root nodules of legumes and actinorhizal (Frankia-nodulated) plants. In root nodules of Datisca glomerata (Datiscaceae), transcripts hybridizing to a conserved coding region of the abundant nodule isoform, DgGS1

  15. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    Science.gov (United States)

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong

    2015-04-28

    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Bacterial-induced calcium oscillations are common to nitrogen-fixing associations of nodulating legumes and nonlegumes.

    Science.gov (United States)

    Granqvist, Emma; Sun, Jongho; Op den Camp, Rik; Pujic, Petar; Hill, Lionel; Normand, Philippe; Morris, Richard J; Downie, J Allan; Geurts, Rene; Oldroyd, Giles E D

    2015-08-01

    Plants that form root-nodule symbioses are within a monophyletic 'nitrogen-fixing' clade and associated signalling processes are shared with the arbuscular mycorrhizal symbiosis. Central to symbiotic signalling are nuclear-associated oscillations in calcium ions (Ca(2+) ), occurring in the root hairs of several legume species in response to the rhizobial Nod factor signal. In this study we expanded the species analysed for activation of Ca(2+) oscillations, including nonleguminous species within the nitrogen-fixing clade. We showed that Ca(2+) oscillations are a common feature of legumes in their association with rhizobia, while Cercis, a non-nodulating legume, does not show Ca(2+) oscillations in response to Nod factors from Sinorhizobium fredii NGR234. Parasponia andersonii, a nonlegume that can associate with rhizobia, showed Nod factor-induced calcium oscillations to S. fredii NGR234 Nod factors, but its non-nodulating sister species, Trema tomentosa, did not. Also within the nitrogen-fixing clade are actinorhizal species that associate with Frankia bacteria and we showed that Alnus glutinosa induces Ca(2+) oscillations in root hairs in response to exudates from Frankia alni, but not to S. fredii NGR234 Nod factors. We conclude that the ability to mount Ca(2+) oscillations in response to symbiotic bacteria is a common feature of nodulating species within the nitrogen-fixing clade.

  17. Novel expression pattern of cytosolic gln synthetase in nitrogen-fixing root nodules of the actinorhizal host, Datisca glomerata

    NARCIS (Netherlands)

    Berry, A.M.; Murphy, T.M.; Okubara, P.A.; Jacobsen, K.R.; Swensen, S.M.; Pawlowski, K.

    2004-01-01

    Gln synthetase (GS) is the key enzyme of primary ammonia assimilation in nitrogen-fixing root nodules of legumes and actinorhizal (Frankia-nodulated) plants. In root nodules of Datisca glomerata (Datiscaceae), transcripts hybridizing to a conserved coding region of the abundant nodule isoform,

  18. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Montaña, José Salvador; Martínez, María Mercedes

    With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB) of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen

  19. Seabird nutrient subsidies benefit non-nitrogen fixing trees and alter species composition in South American coastal dry forests

    NARCIS (Netherlands)

    Havik, G.; Catenazzi, A.; Holmgren, M.

    2014-01-01

    Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing spec

  20. Endophytic Actinobacteria and the Interaction of Micromonospora and Nitrogen Fixing Plants.

    Science.gov (United States)

    Trujillo, Martha E; Riesco, Raúl; Benito, Patricia; Carro, Lorena

    2015-01-01

    For a long time, it was believed that a healthy plant did not harbor any microorganisms within its tissues, as these were often considered detrimental for the plant. In the last three decades, the numbers of studies on plant microbe-interactions has led to a change in our view and we now know that many of these invisible partners are essential for the overall welfare of the plant. The application of Next Generation Sequencing techniques is a powerful tool that has permitted the detection and identification of microbial communities in healthy plants. Among the new plant microbe interactions recently reported several actinobacteria such as Micromonospora are included. Micromonospora is a Gram-positive bacterium with a wide geographical distribution; it can be found in the soil, mangrove sediments, and freshwater and marine ecosistems. In the last years our group has focused on the isolation of Micromonospora strains from nitrogen fixing nodules of both leguminous and actinorhizal plants and reported for the first time its wide distribution in nitrogen fixing nodules of both types of plants. These studies have shown how this microoganism had been largely overlooked in this niche due to its slow growth. Surprisingly, the genetic diversity of Micromonospora strains isolated from nodules is very high and several new species have been described. The current data indicate that Micromonospora saelicesensis is the most frequently isolated species from the nodular tissues of both leguminous and actinorhizal plants. Further studies have also been carried out to confirm the presence of Micromonospora inside the nodule tissues, mainly by specific in situ hybridization. The information derived from the genome of the model strain, Micromonospora lupini, Lupac 08, has provided useful information as to how this bacterium may relate with its host plant. Several strategies potentially necessary for Micromonospora to thrive in the soil, a highly competitive, and rough environment, and

  1. Endophytic Actinobacteria and The Interaction of Micromonospora and Nitrogen Fixing Plants

    Directory of Open Access Journals (Sweden)

    Martha E Trujillo

    2015-12-01

    Full Text Available For a long time, it was believed that a healthy plant did not harbor any microorganisms within its tissues, as these were often considered detrimental for the plant. In the last three decades, the numbers of studies on plant microbe-interactions has led to a change in our view and we now know that many of these invisible partners are essential for the overall welfare of the plant. The application of Next Generation Sequencing techniques is a powerful tool that has permitted the detection and identification of microbial communities in healthy plants. Among the new plant microbe interactions recently reported several actinobacteria such as Micromonospora are included.Micromonospora is a Gram-positive bacterium with a wide geographical distribution; it can be found in the soil, mangrove sediments, and freshwater and marine ecosistems. In the last years our group has focused on the isolation of Micromonospora strains from nitrogen fixing nodules of both leguminous and actinorhizal plants and reported for the first time its wide distribution in nitrogen fixing nodules of both types of plants. These studies have shown how this microoganism had been largely overlooked in this niche due to its slow growth. Surprisingly, the genetic diversity of Micromonospora strains isolated from nodules is very high and several new species have been described. The current data indicate that Micromonospora saelicesensis is the most frequently isolated species from the nodular tissues of both leguminous and actinorhizal plants. Further studies have also been carried out to confirm the presence of Micromonospora inside the nodule tissues, mainly by specific in-situ hybridization.The information derived from the genome of the model strain, Micromonospora lupini, Lupac 08, has provided useful information as to how this bacterium may relate with its host plant. Several strategies potentially necessary for Micromonospora to thrive in the soil, a highly competitive and rough

  2. Azospirillum doebereinerae sp. nov., a nitrogen-fixing bacterium associated with the C4-grass Miscanthus.

    Science.gov (United States)

    Eckert, B; Weber, O B; Kirchhof, G; Halbritter, A; Stoffels, M; Hartmann, A

    2001-01-01

    A new group of nitrogen-fixing Azospirillum sp. bacteria was isolated from the roots of the C4-gramineous plant Miscanthus. Polyphasic taxonomy was performed, including auxanography using API galleries, physiological tests and 16S rRNA sequence comparison. The ability of the isolates to fix dinitrogen was evaluated by amplification of the nifD gene, immunodetection of the dinitrogenase reductase and acetylene-reduction assay. On the basis of these results, the nitrogen-fixing isolates represent a new species within the genus Azospirillum. Its closest phylogenetic neighbours, as deduced by 16S rDNA-based analysis, are Azospirillum lipoferum, Azospirillum largimobile and Azospirillum brasilense with 96.6, 96.6 and 95.9% sequence similarity, respectively. Two 16S rRNA-targeting oligonucleotide probes were developed which differentiate the new species from the other Azospirillum species by whole-cell fluorescence hybridization. Strains of the new species are curved rods or S-shaped, 1.0-1.5 microm in width and 2,0-3.0 microm in length, Gram-negative and motile with a single polar flagellum. Optimum growth occurs at 30 degrees C and at pH values between 6.0 and 7.0. No growth takes place at 37 degrees C. They have a respiratory type of metabolism, grow well on arabinose, D-fructose, gluconate, glucose, glycerol, malate, mannitol and sorbitol. They differ from A. largimobile and A. lipoferum by their inability to use N-acetylglucosamine and D-ribose, from A. lipoferum by their ability to grow without biotin supplementation and from A. brasilense by their growth with D-mannitol and D-sorbitol as sole carbon sources. Nitrogen fixation occurs in microaerobic nitrogen-limited conditions. For this species, the name Azospirillum doebereinerae sp. nov. is suggested, with strain GSF71T as the type strain (= DSM 13131T; reference strain Ma4 = DSM 13400). Its G+C content is 70.7 mol%.

  3. Draft Genome sequence of Frankia sp. Strain QA3, a nitrogen-fixing actinobacterium isolated from the root nodule of Alnus nitida

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Arnab [University of North Bengal, Siliguri, India; Beauchemin, Nicholas [University of New Hampshire; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Davenport, Karen W. [Los Alamos National Laboratory (LANL); Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Furnholm, Teal [University of New Hampshire; Ghodhbane-Gtari, Faten [University of New Hampshire; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Gtari, Maher [University of New Hampshire; Han, James [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Nouioui, Imen [University of Tunis-El Manar, Tunisia; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Santos, Catarina [Instiuto Celular e Aplicada, Portugal; Sur, Saubashya [University of North Bengal, Siliguri, India; Szeto, Ernest [U.S. Department of Energy, Joint Genome Institute; Tavares, Fernando [Instiuto Celular e Aplicada, Portugal; Teshima, Hazuki [Los Alamos National Laboratory (LANL); Thakur, Subarna [University of North Bengal, Siliguri, India; Wall, Luis [University of Quilmes, Argentina; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Wishart, Jessie [University of New Hampshire; Tisa, Louis S. [University of New Hampshire

    2013-01-01

    Members of actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a high-quality draft genome sequence for Frankia sp. stain QA3, a nitrogen-fixing actinobacterium isolated from root nodules of Alnus nitida.

  4. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Directory of Open Access Journals (Sweden)

    Aulie Banerjee

    Full Text Available Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13C NMR, we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  5. A common genomic framework for a diverse assembly of plasmids in the symbiotic nitrogen fixing bacteria.

    Directory of Open Access Journals (Sweden)

    Lisa C Crossman

    Full Text Available This work centres on the genomic comparisons of two closely-related nitrogen-fixing symbiotic bacteria, Rhizobium leguminosarum biovar viciae 3841 and Rhizobium etli CFN42. These strains maintain a stable genomic core that is also common to other rhizobia species plus a very variable and significant accessory component. The chromosomes are highly syntenic, whereas plasmids are related by fewer syntenic blocks and have mosaic structures. The pairs of plasmids p42f-pRL12, p42e-pRL11 and p42b-pRL9 as well large parts of p42c with pRL10 are shown to be similar, whereas the symbiotic plasmids (p42d and pRL10 are structurally unrelated and seem to follow distinct evolutionary paths. Even though purifying selection is acting on the whole genome, the accessory component is evolving more rapidly. This component is constituted largely for proteins for transport of diverse metabolites and elements of external origin. The present analysis allows us to conclude that a heterogeneous and quickly diversifying group of plasmids co-exists in a common genomic framework.

  6. Secretion systems and signal exchange between nitrogen-fixing rhizobia and legumes.

    Science.gov (United States)

    Nelson, Matthew S; Sadowsky, Michael J

    2015-01-01

    The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.

  7. Ants are less attracted to the extrafloral nectar of plants with symbiotic, nitrogen-fixing rhizobia.

    Science.gov (United States)

    Godschalx, Adrienne L; Schädler, Martin; Trisel, Julie A; Balkan, Mehmet A; Ballhorn, Daniel J

    2015-02-01

    Plants simultaneously maintain mutualistic relationships with different partners that are connected through the same host, but do not interact directly. One or more participating mutualists may alter their host's phenotype, resulting in a shift in the host's ecological interactions with all other mutualists involved. Understanding the functional interplay of mutualists associated with the same host remains an important challenge in biology. Here, we show belowground nitrogen-fixing rhizobia on lima bean (Phaseolus lunatus) alter their host plant's defensive mutualism with aboveground ants. We induced extrafloral nectar (EFN), an indirect defense acting through ant attraction. We also measured various nutritive and defensive plant traits, biomass, and counted ants on rhizobial and rhizobia-free plants. Rhizobia increased plant protein as well as cyanogenesis, a direct chemical defense against herbivores, but decreased EFN. Ants were significantly more attracted to rhizobia-free plants, and our structural equation model shows a strong link between rhizobia and reduced EFN as well as between EFN and ants: the sole path to ant recruitment. The rhizobia-mediated effects on simultaneously expressed defensive plant traits indicate rhizobia can have significant bottom-up effects on higher trophic levels. Our results show belowground symbionts play a critical and underestimated role in determining aboveground mutualistic interactions.

  8. Comparison of biomass productivity and nitrogen fixing potential of Azolla SPP

    Energy Technology Data Exchange (ETDEWEB)

    Arora, A.; Singh, P.K. [Indian Agricultural Research Inst., New Delhi (India)

    2003-03-01

    Study was conducted on six different Azolla species, available in the germplasm collection of NCCUBGA, IARI, New Delhi namely A. filiculoides, A. mexicana, A. microphylla, A. pinnata, A. rubra and A. caroliniana in a polyhouse to assess their growth potential by determining their maximal biomass productivity, doubling time and relative growth rates. Their nitrogen fixing potential was assessed by acetylene reduction assay. Among them Azolla microphylla gave highest biomass production and relative growth rate followed by Azolla caroliniana. Both these had high nitrogenase activity also. Peak nitrogenase activity of these strains was found on 14th day of growth and it declined on further incubation. Azolla microphylla and Azolla rubra were more tolerant to salinity than others. On the other hand Azolla pinnata, which is endemic species found in India, exhibited low biomass production, relative growth rate and lower nitrogenase activity compared to other species. It was unable to sustain growth in saline medium. Under polyhouse conditions, A. microphylla was found to perform better than other cultures in terms of biomass productivity, N fixing ability and salt tolerance. Hence it is taken up for mass production.(author)

  9. Paenibacillus sonchi sp. nov., a nitrogen-fixing species isolated from the rhizosphere of Sonchus oleraceus.

    Science.gov (United States)

    Hong, Yuan-Yuan; Ma, Yu-Chao; Zhou, Yu-Guang; Gao, Fei; Liu, Hong-Can; Chen, San-Feng

    2009-11-01

    A nitrogen-fixing bacterium, designated strain X19-5(T), was isolated from rhizosphere soil of Sonchus oleraceus. Phylogenetic analysis based on a fragment of the nifH gene and the full-length 16S rRNA gene sequence revealed that strain X19-5(T) was a member of the genus Paenibacillus. Strain X19-5(T) showed the highest 16S rRNA gene sequence similarity (98.8 %) with Paenibacillus graminis RSA19(T) and below 97 % similarity with other recognized members of the genus. The level of DNA-DNA relatedness between strain X19-5(T) and P. graminis RSA19(T) was 45.7 %. The DNA G+C content of strain X19-5(T) was 46.8 mol%. The major fatty acids were anteiso-C(15 : 0), C(16 : 0) and iso-C(16 : 0). On the basis of its phenotypic characteristics and the level of DNA-DNA hybridization, strain X19-5(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus sonchi sp. nov. is proposed. The type strain is X19-5(T) (=CCBAU 83901(T)=LMG 24727(T)).

  10. Microbial community structure and functional diversity of nitrogen-fixing bacteria associated with Colophospermum mopane.

    Science.gov (United States)

    Burbano, Claudia Sofía; Grönemeyer, Jann Lasse; Hurek, Thomas; Reinhold-Hurek, Barbara

    2015-04-01

    Colophospermum mopane is an indigenous legume tree that grows in Southern Africa and is one of the predominant trees of the woodland vegetation. In order to increase knowledge about its ecology, especially how C. mopane thrives in the nitrogen-poor soils of the region, we analyzed the root-associated bacteria to assess the active diazotrophic diversity and total microbial diversity by culture-dependent and independent techniques. Root nodules were not detected but in some samples the lateral roots showed an outgrowth-like protuberance, that were not likely to have functions related to legume root nodules. The bacterial isolates recovered were related to Actinobacteria, Firmicutes and Proteobacteria. The total microbial diversity was dominated by Actinobacteria-related phylotypes, while the active diazotrophic diversity showed that the majority of the sequences were related to the order Rhizobiales but also to Spirochaetes, Firmicutes, Bacteroidetes and Deltaproteobacteria. Several isolates showed characteristics of plant growth-promoting bacteria. These findings increase the spectrum of possible phylotypes that can be found in legume trees that are typically nodulated by Alpha- and Betaproteobacteria, and reveal for the first time a surprising diversity of nitrogen-fixing bacteria active in legume tree roots. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Use of nitrogen-fixing bacteria as biofertiliser for non-legumes: prospects and challenges.

    Science.gov (United States)

    Bhattacharjee, Rumpa Biswas; Singh, Aqbal; Mukhopadhyay, S N

    2008-08-01

    The potential of nitrogen-fixing (NF) bacteria to form a symbiotic relationship with leguminous plants and fix atmospheric nitrogen has been exploited in the field to meet the nitrogen requirement of the latter. This phenomenon provides an alternative to the use of the nitrogenous fertiliser whose excessive and imbalanced use over the decades has contributed to green house emission (N2O) and underground water leaching. Recently, it was observed that non-leguminous plants like rice, sugarcane, wheat and maize form an extended niche for various species of NF bacteria. These bacteria thrive within the plant, successfully colonizing roots, stems and leaves. During the association, the invading bacteria benefit the acquired host with a marked increase in plant growth, vigor and yield. With increasing population, the demand of non-leguminous plant products is growing. In this regard, the richness of NF flora within non-leguminous plants and extent of their interaction with the host definitely shows a ray of hope in developing an ecofriendly alternative to the nitrogenous fertilisers. In this review, we have discussed the association of NF bacteria with various non-leguminous plants emphasizing on their potential to promote host plant growth and yield. In addition, plant growth-promoting traits observed in these NF bacteria and their mode of interaction with the host plant have been described briefly.

  12. Impact of five insecticides on chickpea (Cicer arietinum L. nodulation, yield and nitrogen fixing rhizospheric bacteria

    Directory of Open Access Journals (Sweden)

    H. Khan

    2009-05-01

    Full Text Available A field experiment was conducted to study the effect of five insecticides i.e. Lorsban (40% EC, Decis (25% EC, Pyrifos (40% EC, Karate (25% EC, and Ripcord (10% EC on the survival of rhizosphere N2-fixing microorganisms, nodulation, pod damage (by pod borer, and grain yield of chickpea (Cicer arietinum L. crop. The study revealed that Pyrifos suppressed nodulation in chickpea and specific rhizobial counts in the crop rhizosphere, indicating that this insecticide was harmful to rhizobial population in rhizosphere. All the other tested insecticides were safe as they did not affect nodulation of the crop and the specific rhizobial counts in the rhizosphere. The results also revealed that all the tested insecticides except Lorsban (40% EC suppressed Azotobacter population in the rhizospheric soil indicating that Lorsban was harmless to Azotobacter while all other tested insecticides were harmful to the survival of this important nitrogen fixing bacterium. Pyrifos proved to be the most effective insecticide in controlling the pod borer damage and also in increasing the grain yield significantly as compared to other tested insecticides.

  13. Nitrogen-fixing bacteria and arbuscular mycorrhizal fungi in Piptadenia gonoacantha (Mart.) Macbr.

    Science.gov (United States)

    Júnior, Joel Quintino de Oliveira; Jesus, Ederson da Conceição; Lisboa, Francy Junio; Berbara, Ricardo Luis Louro; Faria, Sergio Miana de

    The family Leguminosae comprises approximately 20,000 species that mostly form symbioses with arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (NFB). This study is aimed at investigating and confirming the dependence on nodulation and biological nitrogen fixation in the specie Piptadenia gonoacantha (Mart.) Macbr., which belongs to the Piptadenia group. Two consecutive experiments were performed in a greenhouse. The experiments were fully randomized with six replicates and a factorial scheme. For the treatments, the two AMF species and three NFB strains were combined to nodulate P. gonoacantha in addition to the control treatments. The results indicate this species' capacity for nodulation without the AMF; however, the AMF+NFB combinations yielded a considerable gain in P. gonoacantha shoot weight compared with the treatments that only included inoculating with bacteria or AMF. The results also confirm that the treatment effects among the AMF+NFB combinations produced different shoot dry weight/root dry weight ratios. We conclude that AMF is not necessary for nodulation and that this dependence improves species development because plant growth increases upon co-inoculation. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  14. Nitrogen-fixing bacteria, arbuscular mycorrhizal fungi, and the productivity and structure of prairie grassland communities.

    Science.gov (United States)

    Bauer, Jonathan T; Kleczewski, Nathan M; Bever, James D; Clay, Keith; Reynolds, Heather L

    2012-12-01

    Due to their complementary roles in meeting plant nutritional needs, arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (N(2)-fixers) may have synergistic effects on plant communities. Using greenhouse microcosms, we tested the effects of AMF, N(2)-fixers (symbiotic: rhizobia, and associative: Azospirillum brasilense), and their potential interactions on the productivity, diversity, and species composition of diverse tallgrass prairie communities and on the productivity of Panicum virgatum in monoculture. Our results demonstrate the importance of AMF and N(2)-fixers as drivers of plant community structure and function. In the communities, we found a positive effect of AMF on diversity and productivity, but a negative effect of N(2)-fixers on productivity. Both AMF and N(2)-fixers affected relative abundances of species. AMF shifted the communities from dominance by Elymus canadensis to Sorghastrum nutans, and seven other species increased in abundance with AMF, accounting for the increased diversity. N(2)-fixers led to increases in Astragalus canadensis and Desmanthus illinoense, two legumes that likely benefited from the presence of the appropriate rhizobia symbionts. Sorghastrum nutans declined 44 % in the presence of N(2)-fixers, with the most likely explanation being increased competition from legumes. Panicum monocultures were more productive with AMF, but showed no response to N(2)-fixers, although inference was constrained by low Azospirillum treatment effectivity. We did not find interactions between AMF and N(2)-fixers in communities or Panicum monocultures, indicating that short-term effects of these microbial functional groups are additive.

  15. The genetic diversity of culturable nitrogen-fixing bacteria in the rhizosphere of wheat.

    Science.gov (United States)

    Venieraki, Anastasia; Dimou, Maria; Pergalis, Panagiotis; Kefalogianni, Io; Chatzipavlidis, Iordanis; Katinakis, Panagiotis

    2011-02-01

    A total of 17 culturable nitrogen-fixing bacterial strains associated with the roots of wheat growing in different regions of Greece were isolated and characterized for plant-growth-promoting traits such as auxin production and phosphate solubilization. The phylogenetic position of the isolates was first assessed by the analysis of the PCR-amplified 16S rRNA gene. The comparative sequence analysis and phylogenetic analysis based on 16S rRNA gene sequences show that the isolates recovered in this study are grouped with Azospirillum brasilense, Azospirillum zeae, and Pseudomonas stutzeri. The diazotrophic nature of all isolates was confirmed by amplification of partial nifH gene sequences. The phylogenetic tree based on nifH gene sequences is consistent with 16S rRNA gene phylogeny. The isolates belonging to Azospirillum species were further characterized by examining the partial dnaK gene phylogenetic tree. Furthermore, it was demonstrated that the ipdC gene was present in all Azospirillum isolates, suggesting that auxin is mainly synthesized via the indole-3-pyruvate pathway. Although members of P. stutzeri and A. zeae are known diazotrophic bacteria, to the best of our knowledge, this is the first report of isolation and characterization of strains belonging to these bacterial genera associated with wheat.

  16. EFFECT OF NITROGEN-FIXING BACTERIA ON GRAIN YIELD AND DEVELOPMENT OF FLOODED IRRIGATED RICE

    Directory of Open Access Journals (Sweden)

    AMAURI NELSON BEUTLER

    2016-01-01

    Full Text Available This study aimed at evaluating the effect of Azospirillum brasilense , a nitrogen - fixing bacterium, on flooded irrigated rice yield. Evaluations were carried out in a shaded nursery, with seedlings grown on an Alfisol. Were performed two sets of experiments. In the first, were carried out four experiments using the flooded rice cultivars INIA Olimar, Puitá Inta - CL, Br Irga 409 and Irga 424; these trials were set up as completely randomized design in a 5x4 factorial scheme, with four replications. Treatments consisted of five nitrogen rates (0, 40, 80, 120 and 160 kg ha - 1 and four levels of liquid inoculant Ab - V5 and Ab - V6 - A. brasilense (0, 1, 2 and 4 times the manufacturer's recommendation without seed treatment. In second set, were performed two experiments using the cultivars Puitá Inta - CL and Br Irga 409, arranged in the same design, but using a 4x2 factorial. In this set, treatments were composed of four levels of Ab - V5 and Ab - V6 - A. brasilense liquid inoculant (0, 1, 2 and 4 times the recommendation of 100 mL ha - 1 , using rice seeds with and without insecticide and fungicide treatment. Shoot dry matter, number of panicles, and rice grain yield per pot were the assessed variables. The results showed that rice seed inoculation with A. brasilense had no effects on rice grain yield of the cultivars INIA Olimar, Puitá Inta - CL, Br Irga 409 and Irga 424.

  17. Azospirillum canadense sp. nov., a nitrogen-fixing bacterium isolated from corn rhizosphere.

    Science.gov (United States)

    Mehnaz, Samina; Weselowski, Brian; Lazarovits, George

    2007-03-01

    A free-living diazotrophic strain, DS2(T), was isolated from corn rhizosphere. Polyphasic taxonomy was performed including morphological characterization, Biolog analysis, and 16S rRNA, cpn60 and nifH gene sequence analyses. 16S rRNA gene sequence analysis indicated that strain DS2(T) was closely related to the genus Azospirillum (96 % similarity). Chemotaxonomic characteristics (DNA G+C content 67.9 mol%; Q-10 quinone system; major fatty acid 18 : 1omega7c) were also similar to those of the genus Azospirillum. In all the analyses, including phenotypic characterization using Biolog analysis and comparison of cellular fatty acids, this isolate was found to be different from the closely related species Azospirillum lipoferum, Azospirillum oryzae and Azospirillum brasilense. On the basis of these results, a novel species is proposed for this nitrogen-fixing strain. The name Azospirillum canadense sp. nov. is suggested with the type strain DS2(T) (=NCCB 100108(T)=LMG 23617(T)).

  18. ROx3: Retinal oximetry utilizing the blue-green oximetry method

    Science.gov (United States)

    Parsons, Jennifer Kathleen Hendryx

    The ROx is a retinal oximeter under development with the purpose of non-invasively and accurately measuring oxygen saturation (SO2) in vivo. It is novel in that it utilizes the blue-green oximetry technique with on-axis illumination. ROx calibration tests were performed by inducing hypoxia in live anesthetized swine and comparing ROx measurements to SO 2 values measured by a CO-Oximeter. Calibration was not achieved to the precision required for clinical use, but limiting factors were identified and improved. The ROx was used in a set of sepsis experiments on live pigs with the intention of tracking retinal SO2 during the development of sepsis. Though conclusions are qualitative due to insufficient calibration of the device, retinal venous SO2 is shown to trend generally with central venous SO2 as sepsis develops. The novel sepsis model developed in these experiments is also described. The method of cecal ligation and perforation with additional soiling of the abdomen consistently produced controllable severe sepsis/septic shock in a matter of hours. In addition, the ROx was used to collect retinal images from a healthy human volunteer. These experiments served as a bench test for several of the additions/modifications made to the ROx. This set of experiments specifically served to illuminate problems with various light paths and image acquisition. The analysis procedure for the ROx is under development, particularly automating the process for consistency, accuracy, and time efficiency. The current stage of automation is explained, including data acquisition processes and the automated vessel fit routine. Suggestions for the next generation of device minimization are also described.

  19. A blue/green water-based accounting framework for assessment of water security

    Science.gov (United States)

    Rodrigues, Dulce B. B.; Gupta, Hoshin V.; Mendiondo, Eduardo M.

    2014-09-01

    A comprehensive assessment of water security can incorporate several water-related concepts, while accounting for Blue and Green Water (BW and GW) types defined in accordance with the hydrological processes involved. Here we demonstrate how a quantitative analysis of provision probability and use of BW and GW can be conducted, so as to provide indicators of water scarcity and vulnerability at the basin level. To illustrate the approach, we use the Soil and Water Assessment Tool (SWAT) to model the hydrology of an agricultural basin (291 km2) within the Cantareira Water Supply System in Brazil. To provide a more comprehensive basis for decision making, we analyze the BW and GW-Footprint components against probabilistic levels (50th and 30th percentile) of freshwater availability for human activities, during a 23 year period. Several contrasting situations of BW provision are distinguished, using different hydrological-based methodologies for specifying monthly Environmental Flow Requirements (EFRs), and the risk of natural EFR violation is evaluated by use of a freshwater provision index. Our results reveal clear spatial and temporal patterns of water scarcity and vulnerability levels within the basin. Taking into account conservation targets for the basin, it appears that the more restrictive EFR methods are more appropriate than the method currently employed at the study basin. The blue/green water-based accounting framework developed here provides a useful integration of hydrologic, ecosystem and human needs information on a monthly basis, thereby improving our understanding of how and where water-related threats to human and aquatic ecosystem security can arise.

  20. Algae -- a poor man's HAART?

    Science.gov (United States)

    Teas, Jane; Hebert, James R; Fitton, J Helen; Zimba, Paul V

    2004-01-01

    Drawing inferences from epidemiologic studies of HIV/AIDS and in vivo and in vitro HIV inhibition by algae, we propose algal consumption as one unifying characteristic of countries with anomalously low rates. HIV/AIDS incidence and prevalence in Eastern Asia ( approximately 1/10000 adults in Japan and Korea), compared to Africa ( approximately 1/10 adults), strongly suggest that differences in IV drug use and sexual behavior are insufficient to explain the 1000-fold variation. Even in Africa, AIDS/HIV rates vary. Chad has consistently reported low rates of HIV/AIDS (2-4/100). Possibly not coincidentally, most people in Japan and Korea eat seaweed daily and the Kanemba, one of the major tribal groups in Chad, eat a blue green alga (Spirulina) daily. Average daily algae consumption in Asia and Africa ranges between 1 and 2 tablespoons (3-13 g). Regular consumption of dietary algae might help prevent HIV infection and suppress viral load among those infected.

  1. Short-term fertilizer application alters phenotypic traits of symbiotic nitrogen fixing bacteria

    Directory of Open Access Journals (Sweden)

    Anna K. Simonsen

    2015-10-01

    Full Text Available Fertilizer application is a common anthropogenic alteration to terrestrial systems. Increased nutrient input can impact soil microbial diversity or function directly through altered soil environments, or indirectly through plant-microbe feedbacks, with potentially important effects on ecologically-important plant-associated mutualists. We investigated the impacts of plant fertilizer, containing all common macro and micronutrients on symbiotic nitrogen-fixing bacteria (rhizobia, a group of bacteria that are important for plant productivity and ecosystem function. We collected rhizobia nodule isolates from natural field soil that was treated with slow-release plant fertilizer over a single growing season and compared phenotypic traits related to free-living growth and host partner quality in these isolates to those of rhizobia from unfertilized soils. Through a series of single inoculation assays in controlled glasshouse conditions, we found that isolates from fertilized field soil provided legume hosts with higher mutualistic benefits. Through growth assays on media containing variable plant fertilizer concentrations, we found that plant fertilizer was generally beneficial for rhizobia growth. Rhizobia isolated from fertilized field soil had higher growth rates in the presence of plant fertilizer compared to isolates from unfertilized field soil, indicating that plant fertilizer application favoured rhizobia isolates with higher abilities to utilize fertilizer for free-living growth. We found a positive correlation between growth responses to fertilizer and mutualism benefits among isolates from fertilized field soil, demonstrating that variable plant fertilizer induces context-dependent genetic correlations, potentially changing the evolutionary trajectory of either trait through increased trait dependencies. Our study shows that short-term application is sufficient to alter the composition of rhizobia isolates in the population or community

  2. Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils.

    Science.gov (United States)

    Pajares, Silvia; Bohannan, Brendan J M

    2016-01-01

    Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research.

  3. Temporal dynamics of abundance and composition of nitrogen-fixing communities across agricultural soils.

    Directory of Open Access Journals (Sweden)

    Michele C Pereira E Silva

    Full Text Available BACKGROUND: Despite the fact that the fixation of nitrogen is one of the most significant nutrient processes in the terrestrial ecosystem, a thorough study of the spatial and temporal patterns in the abundance and distribution of N-fixing communities has been missing so far. METHODOLOGY/PRINCIPAL FINDINGS: In order to understand the dynamics of diazotrophic communities and their resilience to external changes, we quantified the abundance and characterized the bacterial community structures based on the nifH gene, using real-time PCR, PCR-DGGE and 454-pyrosequencing, across four representative Dutch soils during one growing season. In general, higher nifH gene copy numbers were observed in soils with higher pH than in those with lower pH, but lower numbers were related to increased nitrate and ammonium levels. Results from nifH gene pyrosequencing confirmed the observed PCR-DGGE patterns, which indicated that the N fixers are highly dynamic across time, shifting around 60%. Forward selection on CCA analysis identified N availability as the main driver of these variations, as well as of the evenness of the communities, leading to very unequal communities. Moreover, deep sequencing of the nifH gene revealed that sandy soils (B and D had the lowest percentage of shared OTUs across time, compared with clayey soils (G and K, indicating the presence of a community under constant change. Cosmopolitan nifH species (present throughout the season were affiliated with Bradyrhizobium, Azospirillum and Methylocistis, whereas other species increased their abundances progressively over time, when appropriate conditions were met, as was notably the case for Paenibacilus and Burkholderia. CONCLUSIONS: Our study provides the first in-depth pyrosequencing analysis of the N-fixing community at both spatial and temporal scales, providing insights into the cosmopolitan and specific portions of the nitrogen fixing bacterial communities in soil.

  4. Study of enzymatic properties of phenol oxidase from nitrogen-fixing Azotobacter chroococcum.

    Science.gov (United States)

    Herter, Susanne; Schmidt, Marlen; Thompson, Mark L; Mikolasch, Annett; Schauer, Frieder

    2011-06-24

    Azotobacter chroococcum is a widespread free-living soil bacterium within the genus of Azotobacter known for assimilation of atmospheric nitrogen and subsequent conversion into nitrogenous compounds, which henceforth enrich the nitrogen content of soils. A. chroococcum SBUG 1484, isolated from composted earth, exhibits phenol oxidase (PO) activity when growing under nitrogen-fixing conditions. In the present study we provide incipient analysis of the crude PO activity expressed by A. chroococcum SBUG 1484 within comparative analysis to fungal crude PO from the white-rot fungus Pycnoporus cinnabarinus SBUG-M 1044 and tyrosinase (PPO) from the mushroom Agaricus bisporus in an attempt to reveal desirable properties for exploitation with future recombinant expression of this enzyme. Catalytic activity increased with pre-incubation at 35°C; however 70% of activity remained after pre-treatment at 50°C. Native A. chroococcum crude PO exhibited not only strong preference for 2,6-dimethoxyphenol, but also towards related methoxy-activated substrates as well as substituted ortho-benzenediols from over 40 substrates tested. Presence of CuSO4 enhanced crude phenol oxidase activity up to 30%, whereas NaN3 (0.1 mM) was identified as the most inhibiting substance of all inhibitors tested. Lowest inhibition of crude PO activity occurred after 60 minutes of incubation in presence of 15% methanol and ethanol with 63% and 77% remaining activities respectively, and presence of DMSO even led to increasing oxidizing activities. Substrate scope and inhibitor spectrum strongly differentiated A. chroococcum PO activity comprised in crude extracts from those of PPO and confirmed distinct similarities to fungal PO.

  5. Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical Forest Soils

    Science.gov (United States)

    Pajares, Silvia; Bohannan, Brendan J. M.

    2016-01-01

    Soil microorganisms play important roles in nitrogen cycling within forest ecosystems. Current research has revealed that a wider variety of microorganisms, with unexpected diversity in their functions and phylogenies, are involved in the nitrogen cycle than previously thought, including nitrogen-fixing bacteria, ammonia-oxidizing bacteria and archaea, heterotrophic nitrifying microorganisms, and anammox bacteria, as well as denitrifying bacteria, archaea, and fungi. However, the vast majority of this research has been focused in temperate regions, and relatively little is known regarding the ecology of nitrogen-cycling microorganisms within tropical and subtropical ecosystems. Tropical forests are characterized by relatively high precipitation, low annual temperature fluctuation, high heterogeneity in plant diversity, large amounts of plant litter, and unique soil chemistry. For these reasons, regulation of the nitrogen cycle in tropical forests may be very different from that of temperate ecosystems. This is of great importance because of growing concerns regarding the effect of land use change and chronic-elevated nitrogen deposition on nitrogen-cycling processes in tropical forests. In the context of global change, it is crucial to understand how environmental factors and land use changes in tropical ecosystems influence the composition, abundance and activity of key players in the nitrogen cycle. In this review, we synthesize the limited currently available information regarding the microbial communities involved in nitrogen fixation, nitrification and denitrification, to provide deeper insight into the mechanisms regulating nitrogen cycling in tropical forest ecosystems. We also highlight the large gaps in our understanding of microbially mediated nitrogen processes in tropical forest soils and identify important areas for future research. PMID:27468277

  6. Microencapsulation by spray drying of nitrogen-fixing bacteria associated with lupin nodules.

    Science.gov (United States)

    Campos, Daniela C; Acevedo, Francisca; Morales, Eduardo; Aravena, Javiera; Amiard, Véronique; Jorquera, Milko A; Inostroza, Nitza G; Rubilar, Mónica

    2014-09-01

    Plant growth promoting bacteria and nitrogen-fixing bacteria (NFB) used for crop inoculation have important biotechnological potential as a sustainable fertilization tool. However, the main limitation of this technology is the low inoculum survival rate under field conditions. Microencapsulation of bacterial cells in polymer matrices provides a controlled release and greater protection against environmental conditions. In this context, the aim of this study was to isolate and characterize putative NFB associated with lupin nodules and to evaluate their microencapsulation by spray drying. For this purpose, 21 putative NFB were isolated from lupin nodules and characterized (16S rRNA genes). Microencapsulation of bacterial cells by spray drying was studied using a mixture of sodium alginate:maltodextrin at different ratios (0:15, 1:14, 2:13) and concentrations (15 and 30% solids) as the wall material. The microcapsules were observed under scanning electron microscopy to verify their suitable morphology. Results showed the association between lupin nodules of diverse known NFB and nodule-forming bacteria belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Bacteroidetes. In microencapsulation assays, the 1:14 ratio of sodium alginate:maltodextrin (15% solids) showed the highest cell survival rate (79%), with a microcapsule yield of 27% and spherical microcapsules of 5-50 µm in diameter. In conclusion, diverse putative NFB genera and nodule-forming bacteria are associated with the nodules of lupine plants grown in soils in southern Chile, and their microencapsulation by spray drying using sodium alginate:maltodextrin represents a scalable process to generate a biofertilizer as an alternative to traditional nitrogen fertilization.

  7. Genome erosion in a nitrogen-fixing vertically transmitted endosymbiotic multicellular cyanobacterium.

    Directory of Open Access Journals (Sweden)

    Liang Ran

    can thus be considered at the initial phase of a transition from free-living organism to a nitrogen-fixing plant entity, a transition process which may mimic what drove the evolution of chloroplasts from a cyanobacterial ancestor.

  8. Exopolysaccharides produced by the symbiotic nitrogen-fixing bacteria of leguminosae

    Directory of Open Access Journals (Sweden)

    Cleide Aparecida Bomfeti

    2011-06-01

    Full Text Available The process of biological nitrogen fixation (BNF, performed by symbiotic nitrogen fixing bacteria with legume species, commonly known as α and β rhizobia, provides high sustainability for the ecosystems. Its management as a biotechnology is well succeeded for improving crop yields. A remarkable example of this success is the inoculation of Brazilian soybeans with Bradyrhizobium strains. Rhizobia produce a wide diversity of chemical structures of exopolysaccharides (EPS. Although the role of EPS is relatively well studied in the process of BNF, their economic and environmental potential is not yet explored. These EPS are mostly species-specific heteropolysaccharides, which can vary according to the composition of sugars, their linkages in a single subunit, the repeating unit size and the degree of polymerization. Studies have showed that the EPS produced by rhizobia play an important role in the invasion process, infection threads formation, bacteroid and nodule development and plant defense response. These EPS also confer protection to these bacteria when exposed to environmental stresses. In general, strains of rhizobia that produce greater amounts of EPS are more tolerant to adverse conditions when compared with strains that produce less. Moreover, it is known that the EPS produced by microorganisms are widely used in various industrial activities. These compounds, also called biopolymers, provide a valid alternative for the commonly used in food industry through the development of products with identical properties or with better rheological characteristics, which can be used for new applications. The microbial EPS are also able to increase the adhesion of soil particles favoring the mechanical stability of aggregates, increasing levels of water retention and air flows in this environment. Due to the importance of EPS, in this review we discuss the role of these compounds in the process of BNF, in the adaptation of rhizobia to environmental

  9. Enterobacter sacchari sp. nov., a nitrogen-fixing bacterium associated with sugar cane (Saccharum officinarum L.).

    Science.gov (United States)

    Zhu, Bo; Zhou, Qing; Lin, Li; Hu, Chunjin; Shen, Ping; Yang, Litao; An, Qianli; Xie, Guanlin; Li, Yangrui

    2013-07-01

    Five nitrogen-fixing bacterial strains (SP1(T), NN143, NN144, NN208 and HX148) were isolated from stem, root or rhizosphere soil of sugar cane (Saccharum officinarum L.) plants. Cells were Gram-negative, motile, rods with peritrichous flagella. DNA G+C content was 55.0 ± 0.5 mol%. Sequence determinations and phylogenetic analysis of 16S rRNA gene and rpoB indicated that the strains were affiliated with the genus Enterobacter and most closely related to E. radicincitans DSM 16656(T) and E. oryzae LMG 24251(T). Fluorimetric determination of thermal denaturation temperatures after DNA-DNA hybridization, enterobacterial repetitive intergenic consensus PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry differentiated the whole-genome, genotype and protein profiles from those of E. radicincitans and E. oryzae. The strains' cell fatty acid composition differentiated them from E. radicincitans and E. oryzae by containing a higher level of summed feature 2 (C16 : 1ω7c and/or C16 : 1ω6c) and a lower level of C17 : 0 cyclo. Their physiological and biochemical profiles differentiated them from E. radicincitans by being positive for methyl red test, ornithine decarboxylase and utilization of putrescine, D-arabitol, L-fucose and methyl α-D-glucoside and being negative for arginine dihydrolase, and differentiated them from E. oryzae by being positive for aesculin hydrolysis and utilization of putrescine, D-arabitol and L-rhamnose and being negative for arginine dihydrolase, lysine decarboxylase and utilization of mucate. The five strains therefore represent a novel species, for which the name Enterobacter sacchari sp. nov. is proposed, with the type strain SP1(T) ( = CGMCC 1.12102(T) = LMG 26783(T)).

  10. Diversity of free-Living nitrogen fixing Streptomyces in soils of the badlands of South Dakota.

    Science.gov (United States)

    Dahal, Bibha; NandaKafle, Gitanjali; Perkins, Lora; Brözel, Volker S

    2017-01-01

    Biological Nitrogen Fixation is critical for ecosystem productivity. Select members of Bacteria and Archaea express a nitrogenase enzyme complex that reduces atmospheric nitrogen to ammonia. Several nitrogen fixing bacteria form symbiotic associations with plants, but free-living diazotrophs also contribute a substantial amount of nitrogen to ecosystems. The aim of this study was to isolate and characterize free-living diazotrophs in arid lands of South Dakota Badlands. Samples were obtained from sod tables and the surrounding base in spring and fall. Diazotrophs were isolated on solid nitrogen free medium (NFM) under hypoxic conditions, and their16S rRNA and nifH genes sequenced. nifH was also amplified directly from soil DNA extracts. The 16S rRNA gene data indicated a diversity of putative free-living diazotrophs across 4 phyla (Actinomycetes, Proteobacteria, Bacteroidetes, and Firmicutes), but ∼50% of these clustered with Streptomyces. These Streptomyces isolates grew in liquid NFM in an ammonia-depleted environment. Only 5 of these yielded a nifH gene product using the PolF/PolR primer set. Four of these aligned with nifH of the cyanobacteria Scytonema and Nostoc, and the other one aligned with nifH of Bradyrhizobium. Six selected Streptomyces isolates, three of which were nifH positive by PCR, all indicated (15)N2 incorporation, providing strong support of nitrogen fixation. All nifH amplicons from soil DNA extract resembled Cyanobacteria. This is the first known report of diazotrophic Streptomyces, other than the thermophilic, autotrophic S. thermoautotrophicus. nifH genes of these Streptomyces were related to those from Cyanobacteria. It is possible that the cyanobacteria-like nifH amplicons obtained from soil DNA were associated with Streptomyces.

  11. Short-term fertilizer application alters phenotypic traits of symbiotic nitrogen fixing bacteria.

    Science.gov (United States)

    Simonsen, Anna K; Han, Shery; Rekret, Phil; Rentschler, Christine S; Heath, Katy D; Stinchcombe, John R

    2015-01-01

    Fertilizer application is a common anthropogenic alteration to terrestrial systems. Increased nutrient input can impact soil microbial diversity or function directly through altered soil environments, or indirectly through plant-microbe feedbacks, with potentially important effects on ecologically-important plant-associated mutualists. We investigated the impacts of plant fertilizer, containing all common macro and micronutrients on symbiotic nitrogen-fixing bacteria (rhizobia), a group of bacteria that are important for plant productivity and ecosystem function. We collected rhizobia nodule isolates from natural field soil that was treated with slow-release plant fertilizer over a single growing season and compared phenotypic traits related to free-living growth and host partner quality in these isolates to those of rhizobia from unfertilized soils. Through a series of single inoculation assays in controlled glasshouse conditions, we found that isolates from fertilized field soil provided legume hosts with higher mutualistic benefits. Through growth assays on media containing variable plant fertilizer concentrations, we found that plant fertilizer was generally beneficial for rhizobia growth. Rhizobia isolated from fertilized field soil had higher growth rates in the presence of plant fertilizer compared to isolates from unfertilized field soil, indicating that plant fertilizer application favoured rhizobia isolates with higher abilities to utilize fertilizer for free-living growth. We found a positive correlation between growth responses to fertilizer and mutualism benefits among isolates from fertilized field soil, demonstrating that variable plant fertilizer induces context-dependent genetic correlations, potentially changing the evolutionary trajectory of either trait through increased trait dependencies. Our study shows that short-term application is sufficient to alter the composition of rhizobia isolates in the population or community, either directly

  12. Metagenomic Analysis of Some Potential Nitrogen-Fixing Bacteria in Arable Soils at Different Formation Processes.

    Science.gov (United States)

    Wolińska, Agnieszka; Kuźniar, Agnieszka; Zielenkiewicz, Urszula; Banach, Artur; Izak, Dariusz; Stępniewska, Zofia; Błaszczyk, Mieczysław

    2017-01-01

    The main goal of the study was to determine the diversity of the potential nitrogen-fixing (PNF) bacteria inhabiting agricultural (A) soils versus wastelands serving as controls (C). The soils were classified into three groups based on the formation process: autogenic soils (Albic Luvisols, Brunic Arenosols, Haplic Phaeozem) formed on loess material, hydrogenic soils (Mollic Gleysols, Eutric Fluvisol, Eutric Histosol) formed under the effect of stagnant water and lithogenic soils (Rendzina Leptosols) formed on limestone. In order to determine the preferable conditions for PNF bacteria, the relationships between the soil chemical features and bacterial operational taxonomic units (OTUs) were tested. Additionally, the nitrogen content and fertilisation requirement of the lithogenic (LG), autogenic (AG) and hydrogenic (HG) soils were discussed. The composition of the bacterial communities was analysed with the next-generation sequencing (NGS) by the Ion Torrent™ technology. The sequences were clustered into OTU based on a 99 % similarity threshold. The arable soils tested were distinctly dominated by β-Proteobacteria representatives of PNF bacteria belonging to the genus Burkholderia. Bacteria from the α-Proteobacteria class and Devosia genus were subdominants. A free-living Cyanobacteria population dominated in A rather than in C soils. We have found that both soil agricultural management and soil formation processes are the most conducive factors for PNF bacteria, as a majority of these microorganisms inhabit the AG group of soils, whilst the LG soils with the lowest abundance of PNF bacteria revealed the need for additional mineral fertilisation. Our studies have also indicated that there are close relationships between soil classification with respect to soil formation processes and PNF bacteria preference for occupation of soil niches.

  13. Symbiotic nitrogen-fixing bacterial populations trapped from soils under agroforestry systems in the Western Amazon

    Directory of Open Access Journals (Sweden)

    Paula Marcela Duque Jaramillo

    2013-12-01

    Full Text Available Cowpea (Vigna unguiculata is an important grain-producing legume that can forego nitrogen fertilization by establishing an efficient symbiosis with nitrogen-fixing bacteria. Although inoculating strains have already been selected for this species, little is known about the genotypic and symbiotic diversity of native rhizobia. Recently, Bradyrhizobium has been shown to be the genus most frequently trapped by cowpea in agricultural soils of the Amazon region. We investigated the genetic and symbiotic diversity of 148 bacterial strains with different phenotypic and cultural properties isolated from the nodules of the trap species cowpea, which was inoculated with samples from soils under agroforestry systems from the western Amazon. Sixty non-nodulating strains indicated a high frequency of endophytic strains in the nodules. The 88 authenticated strains had varying symbiotic efficiency. The SPAD (Soil Plant Analysis Development index (indirect measurement of chlorophyll content was more efficient at evaluating the contribution of symbiotic N2-fixation than shoot dry matter under axenic conditions. Cowpea-nodulating bacteria exhibited a high level of genetic diversity, with 68 genotypes identified by BOX-PCR. Sequencing of the 16S rRNA gene showed a predominance of the genus Bradyrhizobium, which accounted for 70 % of all strains sequenced. Other genera identified were Rhizobium, Ochrobactrum, Paenibacillus, Bosea, Bacillus, Enterobacter, and Stenotrophomonas. These results support the promiscuity of cowpea and demonstrate the high genetic and symbiotic diversity of rhizobia in soils under agroforestry systems, with some strains exhibiting potential for use as inoculants. The predominance of Bradyrhizobium in land uses with different plant communities and soil characteristics reflects the adaptation of this genus to the Amazon region.

  14. Improved Alkane Production in Nitrogen-Fixing and Halotolerant Cyanobacteria via Abiotic Stresses and Genetic Manipulation of Alkane Synthetic Genes.

    Science.gov (United States)

    Kageyama, Hakuto; Waditee-Sirisattha, Rungaroon; Sirisattha, Sophon; Tanaka, Yoshito; Mahakhant, Aparat; Takabe, Teruhiro

    2015-07-01

    Cyanobacteria possess the unique capacity to produce alkane. In this study, effects of nitrogen deficiency and salt stress on biosynthesis of alkanes were investigated in three kinds of cyanobacteria. Intracellular alkane accumulation was increased in nitrogen-fixing cyanobacterium Anabaena sp. PCC7120, but decreased in non-diazotrophic cyanobacterium Synechococcus elongatus PCC7942 and constant in a halotolerant cyanobacterium Aphanothece halophytica under nitrogen-deficient condition. We also found that salt stress increased alkane accumulation in Anabaena sp. PCC7120 and A. halophytica. The expression levels of two alkane synthetic genes were not upregulated significantly under nitrogen deficiency or salt stress in Anabaena sp. PCC7120. The transformant Anabaena sp. PCC7120 cells with additional alkane synthetic gene set from A. halophytica increased intracellular alkane accumulation level compared to control cells. These results provide a prospect to improve bioproduction of alkanes in nitrogen-fixing halotolerant cyanobacteria via abiotic stresses and genetic engineering.

  15. Effects of monosulfuron-ester on metabolic processes of nitrogen-fixing cyanobacteria Anabaena flos-aquae and Anabaena azotica.

    Science.gov (United States)

    Shen, Jian Ying; Liao, Jin Zhi; Guo, Li Li; Su, Rui Fang

    Presence of the relatively new sulfonylurea herbicide monosulfuron-ester at 0.03-300nmol/L affected the growth of two non-target nitrogen-fixing cyanobacteria (Anabaena flos-aquae and Anabaena azotica) and substantially inhibited in vitro Acetolactate synthase activity, with IC50 of 3.3 and 101.3nmol/L for A. flos-aquae and A. azotica, respectively. Presenting in 30-300nmol/L, it inhibited protein synthesis of the cyanobacteria with less amino acids produced as its concentration increased. Our findings support the view that monosulfuron-ester toxicity in both nitrogen-fixing cyanobacteria is due to its interference with protein metabolism via inhibition of branch-chain amino acid biosynthesis, and particularly Acetolactate synthase activity. Copyright © 2017. Published by Elsevier Editora Ltda.

  16. Diversity of Nitrogen-Fixing Bacteria Associated with Switchgrass in the Native Tallgrass Prairie of Northern Oklahoma

    OpenAIRE

    Bahulikar, Rahul A.; Torres-Jerez, Ivone; Worley, Eric; Craven, Kelly; Udvardi, Michael K.

    2014-01-01

    Switchgrass (Panicum virgatum L.) is a perennial C4 grass native to North America that is being developed as a feedstock for cellulosic ethanol production. Industrial nitrogen fertilizers enhance switchgrass biomass production but add to production and environmental costs. A potential sustainable alternative source of nitrogen is biological nitrogen fixation. As a step in this direction, we studied the diversity of nitrogen-fixing bacteria (NFB) associated with native switchgrass plants from ...

  17. Diversity of Nitrogen-Fixing Bacteria Associated with Switchgrass in the Native Tallgrass Prairie of Northern Oklahoma

    OpenAIRE

    Bahulikar, Rahul A.; Torres-Jerez, Ivone; Worley, Eric; Craven, Kelly; Udvardi, Michael K.

    2014-01-01

    Switchgrass (Panicum virgatum L.) is a perennial C4 grass native to North America that is being developed as a feedstock for cellulosic ethanol production. Industrial nitrogen fertilizers enhance switchgrass biomass production but add to production and environmental costs. A potential sustainable alternative source of nitrogen is biological nitrogen fixation. As a step in this direction, we studied the diversity of nitrogen-fixing bacteria (NFB) associated with native switchgrass plants from ...

  18. Phylogenetic diversity of nitrogen-fixing bacteria and the nifH gene from mangrove rhizosphere soil.

    Science.gov (United States)

    Liu, Jianyin; Peng, Mengjun; Li, Youguo

    2012-04-01

    Nine types of nitrogen-fixing bacterial strains were isolated from 3 rhizosphere soil samples taken from mangrove plants in the Dongzhaigang National Mangrove Nature Reserve of China. Most isolates belonged to Gammaproteobacteria Pseudomonas, showing that these environments constituted favorable niches for such abundant nitrogen-fixing bacteria. New members of the diazotrophs were also found. Using a soil DNA extraction and PCR-cloning-sequencing approach, 135 clones were analyzed by restriction fragment length polymorphism (RFLP) analysis, and 27 unique nifH sequence phylotypes were identified, most of which were closely related to sequences from uncultured bacteria. The diversity of nitrogen-fixing bacteria was assessed by constructing nifH phylogenetic trees from sequences of all isolates and clones in this work, together with related nifH sequences from other mangrove ecosystems in GenBank. The nifH diversity varied among soil samples, with distinct biogeochemical properties within a mangrove ecosystem. When comparing different mangrove ecosystems, the nifH gene sequences from a specific site tended to cluster as individual groups. The results provided interesting data and novel information on our understanding of diazotroph community diversity in the mangrove ecosystems.

  19. [Amino acid composition of polynucleotide-peptide complexes isolated from algae].

    Science.gov (United States)

    Pusheva, M A; Khoreva, M A

    1977-01-01

    The amino acid composition of the peptide moiety of sulphur containing polynucleotide-peptide complexes (S-PNPC) was studied with four species of green algae and two species of blue-green algae. S-PNPC contained almost all amino acids which were usually encountered in acid hydrolysates of proteins, and also unidentified ninhydrin-positive compounds. The amino acid composition of the peptide moiety of S-PNPC was rather similar in the case of different algae, and was characterized by the prevailence of acid amino acids.

  20. Population dynamics of free living, nitrogen fixing bacteria Azospirillum in Manakkudi mangrove ecosystem, India.

    Science.gov (United States)

    Ravikumar, S; Gnanadesigan, M; Ignatiammal, S Thadedus Maria; Sumaya, S

    2012-05-01

    Seasonal variations of population dynamics of free living nitrogen fixing bacteria, Azospirillum in relation to chemical parameters in Manakkudi mangrove ecosystem was assessed in root and rhizosphere soil samples of mangroves and mangrove associated plants. In rhizosphere soil and root samples, the counts of Azospirillum were recorded maximum in Acrostichum aureum as 8.63 +/- 0.92 x 10(4) and 115.48 +/- 17.36 x 10(4) CFU g(-1), respectively. The counts of Azospirillum in non-rhizosphere soil varied from 0.01 +/- 0.001 x 10(4) to 5.77 +/- 0.92 x 10(4) CFU g(-1) and found maximum in February and minimum in March and September. Azospirillum counts in water samples were found maximum (2.24 x 10(4) CFU l(-1)) in February. During seasonal variations maximum counts of Azospirillum were recorded during southwest monsoon season in Avicennia officinalis (1.40 x 10(4) CFU g(-1)) followed by Rhizophora mucronata (1.07 x 10(4) CFU g(-1)). The average maximum population density of Azospirillum counts was found during non monsoon season (9.73 x 10(4) CFU g(-1)) and the average maximum population density of Azospirillum counts was found with the mangrove associated root samples (13.73 x 10(4) CFU g(-1)). Of the selected isolates Azospirillum lipoferum (60%) was found to be predominant followed by Azospirillum brasilense (25%), Azospirillum irakense (5%), Azospirillum halopraeferens (5%) and Azospirillum amazonense (5%). Of the isolated species, A. halopraeferens exhibited better growth at 35 g l(-1) NaCl. The level of Fe, Cu, Zn and Mn were varied from 0.91 to 15.93 ppm. The level of Mn (12.13 ppm) was found maximum during non-monsoon of rhizosphere soil sample. Highest rainfall (192.80 mm) and atmospheric temperature (25.10 degrees C) were recorded during south west monsoon and non monsoon seasons. The increased population density was greatly influenced by the pH (r = +0.686). The present finding provides enough information on the nitrogen flow through biological process in

  1. Genomic studies of nitrogen-fixing rhizobial strains from Phaseolus vulgaris seeds and nodules.

    Science.gov (United States)

    Peralta, Humberto; Aguilar, Alejandro; Díaz, Rafael; Mora, Yolanda; Martínez-Batallar, Gabriel; Salazar, Emmanuel; Vargas-Lagunas, Carmen; Martínez, Esperanza; Encarnación, Sergio; Girard, Lourdes; Mora, Jaime

    2016-09-06

    Rhizobia are soil bacteria that establish symbiotic relationships with legumes and fix nitrogen in root nodules. We recently reported that several nitrogen-fixing rhizobial strains, belonging to Rhizobium phaseoli, R. trifolii, R. grahamii and Sinorhizobium americanum, were able to colonize Phaseolus vulgaris (common bean) seeds. To gain further insight into the traits that support this ability, we analyzed the genomic sequences and proteomes of R. phaseoli (CCGM1) and S. americanum (CCGM7) strains from seeds and compared them with those of the closely related strains CIAT652 and CFNEI73, respectively, isolated only from nodules. In a fine structural study of the S. americanum genomes, the chromosomes, megaplasmids and symbiotic plasmids were highly conserved and syntenic, with the exception of the smaller plasmid, which appeared unrelated. The symbiotic tract of CCGM7 appeared more disperse, possibly due to the action of transposases. The chromosomes of seed strains had less transposases and strain-specific genes. The seed strains CCGM1 and CCGM7 shared about half of their genomes with their closest strains (3353 and 3472 orthologs respectively), but a large fraction of the rest also had homology with other rhizobia. They contained 315 and 204 strain-specific genes, respectively, particularly abundant in the functions of transcription, motility, energy generation and cofactor biosynthesis. The proteomes of seed and nodule strains were obtained and showed a particular profile for each of the strains. About 82 % of the proteins in the comparisons appeared similar. Forty of the most abundant proteins in each strain were identified; these proteins in seed strains were involved in stress responses and coenzyme and cofactor biosynthesis and in the nodule strains mainly in central processes. Only 3 % of the abundant proteins had hypothetical functions. Functions that were enriched in the genomes and proteomes of seed strains possibly participate in the successful

  2. Floristic account of the marine benthic algae from Jarvis Island and Kingman Reef, Line Islands, Central Pacific

    Directory of Open Access Journals (Sweden)

    Vroom, P.S.

    2012-05-01

    Full Text Available The marine benthic algae from Jarvis Island and Kingman Reef were identified from collections obtained from the Whippoorwill Expedition in 1924, the Itasca Expedition in 1935, the U.S. Coast Guard Cutter Taney in 1938, the Smithsonian Institution’s Pacific Ocean Biological Survey Program in 1964 and the U.S. National Oceanic and Atmospheric Administration’s Reef Assessment and Monitoring Program (RAMP in 2000, 2001, 2002, 2004 and 2006. A total of 124 species, representing 8 Cyanobacteria (blue-green algae, 82 Rhodophyta (red algae, 6 Heterokontophyta (brown algae and 28 Chlorophyta (green algae, are reported from both islands. Seventy-nine and 95 species of marine benthic algae are recorded from Jarvis Island and Kingman Reef, respectively. Of the 124 species, 77 species or 62% (4 blue-green algae, 57 red algae, 2 brown algae and 14 green algae have never before been reported from the 11 remote reefs, atolls and low islands comprising the Line Islands in the Central Pacific.

  3. Effects of pulp mill chlorate on Baltic Sea algae.

    Science.gov (United States)

    Rosemarin, A; Lehtinen, K J; Notini, M; Mattson, J

    1994-01-01

    The long-term effects of pulp mill chlorate on different algal species of the Baltic Sea were studied in land-based model ecosystems simulating the littoral zone. Brown algae (Phaeophyta) exhibited an extraordinarily high sensitivity to chlorate and pulp mill effluents containing chlorate. All brown algal species ceased growth or showed major signs of toxicity at all concentrations tested, down to microgram per litre levels. EC50 levels for growth of Fucus vesiculosus were about 80-100 microg ClO3- litre(-1). Blue-green algae (Cyanophyta) were not deleteriously affected nor were green algae (Chlorophyta). The perennial and annual species of red algae (Rhodophyta) were also unaffected by the effluents. Diatoms did not show any sensitivity and phytoplankton (fresh- and brackish water) were particularly insensitive. A phanerogam, Zostera marina was also unaffected by the treatments.

  4. Computer simulation on kinetics of primary process in photosynthesis of algae (Ⅳ)——Excitation energy transfer in phycobilisomes from blue-green algae

    Institute of Scientific and Technical Information of China (English)

    赵井泉; 朱晋昌; 蒋丽金

    1995-01-01

    A more exact model of phycobilisomes has been designed with the rods composed of the hexamer disks and an abstract allophycocyanin (APC) core. Based on this model, the excitation energy transfer was simulated using the computer simulation technique. The simulation shows that the excitation energy is transferred from the outlayer disk to the core in a partly reversible way in phycobilisomes, and that the transfer rate from the last disk to the core is less than those between disks. The energy transfer between the two trimers in a hexamer is dominantly through the α84-chromophores (m), while that between the disks is through the β84-chromophores (f) that are also responsible for the transfer of energy into the core.

  5. Synthesis, structure, photophysical and electroluminescent properties of a blue-green self-host phosphorescent iridium(III) complex

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jing; Wang, Hua [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Xu, Huixia, E-mail: xuhuixiatyut@163.com [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Li, Jie; Wu, Yuling; Du, Xiaogang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Xu, Bingshe, E-mail: xubs@tyut.edu.cn [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-07-15

    A kind of blue-green self-host phosphorescent iridium(III) complex, (CzPhBI){sub 2}Ir(tfmptz) [CzPhBI = 9-(6-(2-phenyl-1-benzimidazolyl)hexyl)-9-carbazole; tfmptz = 2-(5-trifluoromethyl-1,2,4-triazolyl)pyridine], was designed and synthesized. The synthesized iridium(III) complex was characterized by {sup 1}H NMR, {sup 19}F NMR, FT-IR, elemental analysis and X-ray single-crystal diffraction, respectively. Its thermal properties, optical properties and electrochemical properties were also investigated. The host-free organic electroluminescent devices with the configuration of ITO/MoO{sub 3} (3 nm)/NPB (30 nm)/TAPC (15 nm)/(CzPhBI){sub 2}Ir(tfmptz) (30 nm)/TBPI (30 nm)/LiF (1 nm)/Al (100 nm) had been fabricated. The devices exhibited excellent performance indicating that (CzPhBI){sub 2}Ir(tfmptz) was a promising phosphorescent material. - Highlights: • A blue-green self-host phosphorescent iridium(III) complex was synthesized. • The molecular structure, and photophysical properties were investigated. • Electroluminescent performance in host-free devices were discussed. • The maximum current efficiency 8.2 cd A{sup −1} and the maximum brightness 5420 cd m{sup −2} were achieved.

  6. Soft gel medium solidified with gellan gum for preliminary screening for root-associating, free-living nitrogen-fixing bacteria inhabiting the rhizoplane of plants

    OpenAIRE

    Hashidoko, Yasuyuki; Tada, Motohiko; Osaki, Mitsuru; Tahara, Satoshi

    2002-01-01

    For preliminary screening for and characterization of free-living nitrogen-fixing bacteria from rhizoplane microflora, we used Winogradsky's mineral mixture-based nitrogen-free medium solidified with 0.3% gellan gum. The soft gel medium enabled some reference and wild free-living nitrogen-fixing bacteria to grow in characteristic colonies, including their reaction to oxygen and their motility change. Gellan gum is thus likely to be a better gel matrix than agarose for the investigation of roo...

  7. Genetic Diversity of Nitrogen-Fixing and Plant Growth Promoting Pseudomonas Species Isolated from Sugarcane Rhizosphere

    Directory of Open Access Journals (Sweden)

    Hai-Bi Li

    2017-07-01

    Full Text Available The study was designed to isolate and characterize Pseudomonas spp. from sugarcane rhizosphere, and to evaluate their plant- growth- promoting (PGP traits and nitrogenase activity. A biological nitrogen-fixing microbe has great potential to replace chemical fertilizers and be used as a targeted biofertilizer in a plant. A total of 100 isolates from sugarcane rhizosphere, belonging to different species, were isolated; from these, 30 isolates were selected on the basis of preliminary screening, for in vitro antagonistic activities against sugarcane pathogens and for various PGP traits, as well as nitrogenase activity. The production of IAA varied from 312.07 to 13.12 μg mL−1 in tryptophan supplemented medium, with higher production in AN15 and lower in CN20 strain. The estimation of ACC deaminase activity, strains CY4 and BA2 produced maximum and minimum activity of 77.0 and 15.13 μmoL mg−1 h−1. For nitrogenase activity among the studied strains, CoA6 fixed higher and AY1 fixed lower in amounts (108.30 and 6.16 μmoL C2H2 h−1 mL−1. All the strains were identified on the basis of 16S rRNA gene sequencing, and the phylogenetic diversity of the strains was analyzed. The results identified all strains as being similar to Pseudomonas spp. Polymerase chain reaction (PCR amplification of nifH and antibiotic genes was suggestive that the amplified strains had the capability to fix nitrogen and possessed biocontrol activities. Genotypic comparisons of the strains were determined by BOX, ERIC, and REP PCR profile analysis. Out of all the screened isolates, CY4 (Pseudomonas koreensis and CN11 (Pseudomonas entomophila showed the most prominent PGP traits, as well as nitrogenase activity. Therefore, only these two strains were selected for further studies; Biolog profiling; colonization through green fluorescent protein (GFP-tagged bacteria; and nifH gene expression using quantitative real-time polymerase chain reaction (qRT-PCR analysis. The

  8. Genetic Diversity of Nitrogen-Fixing and Plant Growth Promoting Pseudomonas Species Isolated from Sugarcane Rhizosphere.

    Science.gov (United States)

    Li, Hai-Bi; Singh, Rajesh K; Singh, Pratiksha; Song, Qi-Qi; Xing, Yong-Xiu; Yang, Li-Tao; Li, Yang-Rui

    2017-01-01

    The study was designed to isolate and characterize Pseudomonas spp. from sugarcane rhizosphere, and to evaluate their plant- growth- promoting (PGP) traits and nitrogenase activity. A biological nitrogen-fixing microbe has great potential to replace chemical fertilizers and be used as a targeted biofertilizer in a plant. A total of 100 isolates from sugarcane rhizosphere, belonging to different species, were isolated; from these, 30 isolates were selected on the basis of preliminary screening, for in vitro antagonistic activities against sugarcane pathogens and for various PGP traits, as well as nitrogenase activity. The production of IAA varied from 312.07 to 13.12 μg mL(-1) in tryptophan supplemented medium, with higher production in AN15 and lower in CN20 strain. The estimation of ACC deaminase activity, strains CY4 and BA2 produced maximum and minimum activity of 77.0 and 15.13 μmoL mg(-1) h(-1). For nitrogenase activity among the studied strains, CoA6 fixed higher and AY1 fixed lower in amounts (108.30 and 6.16 μmoL C2H2 h(-1) mL(-1)). All the strains were identified on the basis of 16S rRNA gene sequencing, and the phylogenetic diversity of the strains was analyzed. The results identified all strains as being similar to Pseudomonas spp. Polymerase chain reaction (PCR) amplification of nifH and antibiotic genes was suggestive that the amplified strains had the capability to fix nitrogen and possessed biocontrol activities. Genotypic comparisons of the strains were determined by BOX, ERIC, and REP PCR profile analysis. Out of all the screened isolates, CY4 (Pseudomonas koreensis) and CN11 (Pseudomonas entomophila) showed the most prominent PGP traits, as well as nitrogenase activity. Therefore, only these two strains were selected for further studies; Biolog profiling; colonization through green fluorescent protein (GFP)-tagged bacteria; and nifH gene expression using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The Biolog phenotypic

  9. Rhizosphere-bacterial community in Eperua falcata (Caesalpiniaceae) a putative nitrogen-fixing tree from French Guiana rainforest.

    Science.gov (United States)

    Villadas, P J; Fernández-López, M; Ramírez-Saad, H; Toro, N

    2007-02-01

    The rainforest of French Guiana is still largely unaffected by human activity. Various pristine sites like the Paracou Research Station are devoted to study this tropical ecosystem. We used culture-independent techniques, like polymerase chain reaction-temperature gradient gel electrophoresis, and construction of clone libraries of partial 16S rRNA and nifH genes, to analyze the composition of the bacterial community in the rhizosphere of mature trees of Eperua falcata and Dicorynia guianensis, both species within the Caesalpiniaceae family. E. falcata is one of the more abundant pioneer tree species in this ecosystem and so far, no root nodules have ever been found. However, its nitrogen-fixing status is regarded as "uncertain", whereas D. guianensis is clearly considered a non-nitrogen-fixing plant. The rhizospheres of these mature trees contain specific bacterial communities, including several currently found uncultured microorganisms. In these communities, there are putative nitrogen-fixing bacteria specifically associated to each tree: D. guianensis harbors several Rhizobium spp. and E. falcata members of the genera Burkholderia and Bradyrhizobium. In addition, nifH sequences in the rhizosphere of the latter tree were very diverse. Retrieved sequences were related to bacteria belonging to the alpha-, beta-, and gamma-Proteobacteria in the E. falcata rhizoplane, whereas only two sequences related to gamma-Proteobacteria were found in D. guianensis. Differences in the bacterial communities and the abundance and diversity of nifH sequences in E. falcata rhizosphere suggest that this tree could obtain nitrogen through a nonnodulating bacterial interaction.

  10. Diversity pattern of nitrogen fixing microbes in nodules of Trifolium arvense (L. at different initial stages of ecosystem development

    Directory of Open Access Journals (Sweden)

    M. Schloter

    2012-09-01

    Full Text Available Legumes can be considered as pioneer plants during ecosystem development, as they form a symbiosis with different nitrogen fixing rhizobia species, which enable the plants to grow on soils with low available nitrogen content. In this study we compared the abundance and diversity of nitrogen fixing microbes based on the functional marker gene nifH, which codes for a subunit of the Fe-protein of the dinitrogenase reductase, in nodules of different size classes of Trifolium arvense (L.. Additionally, carbon and nitrogen contents of the bulk soil and plant material were measured. Plants were harvested from different sites, reflecting 2 (2a and 5 (5a yr of ecosystem development, of an opencast lignite mining area in the south of Cottbus, Lower Lusatia (Germany where the artificial catchment "Chicken Creek" was constructed to study the development of terrestrial ecosystems. Plants from the 5a site revealed higher amounts of carbon and nitrogen, although nifH gene abundances in the nodules and carbon and nitrogen contents between the two soils did not differ significantly. Analysis of the nifH clone libraries showed a significant effect of the nodule size on the community composition of nitrogen fixing microbes. Medium sized nodules (2–5 mm contained a uniform community composed of Rhizobium leguminosarum bv. trifolii, whereas the small nodules (Rhizobium nifH gene sequences. Regarding the impact of the soil age on the community composition a clear distinction between the small and the medium nodules can be made. While clone libraries from the medium nodules were pretty similar at both soil ages, soil age had a significant effect on the community compositions of the small nodules, where the proportion of R. leguminosarum bv. trifolii increased with soil age.

  11. Diversity pattern of nitrogen fixing microbes in nodules of Trifolium arvense (L.) at different initial stages of ecosystem development

    Science.gov (United States)

    Schulz, S.; Engel, M.; Fischer, D.; Buegger, F.; Elmer, M.; Welzl, G.; Schloter, M.

    2013-02-01

    Legumes can be considered as pioneer plants during ecosystem development, as they form a symbiosis with different nitrogen fixing rhizobia species, which enable the plants to grow on soils with low available nitrogen content. In this study we compared the abundance and diversity of nitrogen fixing microbes based on the functional marker gene nifH, which codes for a subunit of the Fe-protein of the dinitrogenase reductase, in nodules of different size classes of Trifolium arvense (L.). Additionally, carbon and nitrogen contents of the bulk soil and plant material were measured. Plants were harvested from different sites, reflecting 2 (2a) and 5 (5a) yr of ecosystem development, of an opencast lignite mining area in the south of Cottbus, Lower Lusatia (Germany) where the artificial catchment "Chicken Creek" was constructed to study the development of terrestrial ecosystems. Plants from the 5a site revealed higher amounts of carbon and nitrogen, although nifH gene abundances in the nodules and carbon and nitrogen contents between the two soils did not differ significantly. Analysis of the nifH clone libraries showed a significant effect of the nodule size on the community composition of nitrogen fixing microbes. Medium sized nodules (2-5 mm) contained a uniform community composed of Rhizobium leguminosarum bv. trifolii, whereas the small nodules (<2 mm) consisted of a diverse community including clones with non-Rhizobium nifH gene sequences. Regarding the impact of the soil age on the community composition a clear distinction between the small and the medium nodules can be made. While clone libraries from the medium nodules were pretty similar at both soil ages, soil age had a significant effect on the community compositions of the small nodules, where the proportion of R. leguminosarum bv. trifolii increased with soil age.

  12. Diversity of Micromonospora strains isolated from nitrogen fixing nodules and rhizosphere of Pisum sativum analyzed by multilocus sequence analysis.

    Science.gov (United States)

    Carro, Lorena; Spröer, Cathrin; Alonso, Pilar; Trujillo, Martha E

    2012-03-01

    It was recently reported that Micromonospora inhabits the intracellular tissues of nitrogen fixing nodules of the wild legume Lupinus angustifolius. To determine if Micromonospora populations are also present in nitrogen fixing nodules of cultivated legumes such as Pisum sativum, we carried out the isolation of this actinobacterium from P. sativum plants collected in two man-managed fields in the region of Castilla and León (Spain). In this work, we describe the isolation of 93 Micromonospora strains recovered from nitrogen fixing nodules and the rhizosphere of P. sativum. The genomic diversity of the strains was analyzed by amplified ribosomal DNA restriction analysis (ARDRA). Forty-six isolates and 34 reference strains were further analyzed using a multilocus sequence analysis scheme developed to address the phylogeny of the genus Micromonospora and to evaluate the species distribution in the two studied habitats. The MLSA results were evaluated by DNA-DNA hybridization to determine their usefulness for the delineation of Micromonospora at the species level. In most cases, DDH values below 70% were obtained with strains that shared a sequence similarity of 98.5% or less. Thus, MLSA studies clearly supported the established taxonomy of the genus Micromonospora and indicated that genomic species could be delineated as groups of strains that share > 98.5% sequence similarity based on the 5 genes selected. The species diversity of the strains isolated from both the rhizosphere and nodules was very high and in many cases the new strains could not be related to any of the currently described species.

  13. An Alternative Approach to "Identification of Unknowns": Designing a Protocol to Verify the Identities of Nitrogen Fixing Bacteria.

    Science.gov (United States)

    Martinez-Vaz, Betsy M; Denny, Roxanne; Young, Nevin D; Sadowsky, Michael J

    2015-12-01

    Microbiology courses often include a laboratory activity on the identification of unknown microbes. This activity consists of providing students with microbial cultures and running biochemical assays to identify the organisms. This approach lacks molecular techniques such as sequencing of genes encoding 16S rRNA, which is currently the method of choice for identification of unknown bacteria. A laboratory activity was developed to teach students how to identify microorganisms using 16S rRNA polymerase chain reaction (PCR) and validate microbial identities using biochemical techniques. We hypothesized that designing an experimental protocol to confirm the identity of a bacterium would improve students' knowledge of microbial identification techniques and the physiological characteristics of bacterial species. Nitrogen-fixing bacteria were isolated from the root nodules of Medicago truncatula and prepared for 16S rRNA PCR analysis. Once DNA sequencing revealed the identity of the organisms, the students designed experimental protocols to verify the identity of rhizobia. An assessment was conducted by analyzing pre- and posttest scores and by grading students' verification protocols and presentations. Posttest scores were higher than pretest scores at or below p = 0.001. Normalized learning gains (G) showed an improvement of students' knowledge of microbial identification methods (LO4, G = 0.46), biochemical properties of nitrogen-fixing bacteria (LO3, G = 0.45), and the events leading to the establishment of nitrogen-fixing symbioses (LO1&2, G = 0.51, G = 0.37). An evaluation of verification protocols also showed significant improvement with a p value of less than 0.001.

  14. Symbiosis between nitrogen-fixing bacteria and Medicago truncatula is not significantly affected by silver and silver sulfide nanomaterials.

    Science.gov (United States)

    Judy, Jonathan D; Kirby, Jason K; McLaughlin, Mike J; McNear, David; Bertsch, Paul M

    2016-07-01

    Silver (Ag) engineered nanomaterials (ENMs) are being released into waste streams and are being discharged, largely as Ag2S aged-ENMs (a-ENMs), into agroecosystems receiving biosolids amendments. Recent research has demonstrated that biosolids containing an environmentally relevant mixture of ZnO, TiO2, and Ag ENMs and their transformation products, including Ag2S a-ENMs, disrupted the symbiosis between nitrogen-fixing bacteria and legumes. However, this study was unable to unequivocally determine which ENM or combination of ENMs and a-ENMs was responsible for the observed inhibition. Here, we examined further the effects of polyvinylpyrollidone (PVP) coated pristine Ag ENMs (PVP-Ag), Ag2S a-ENMs, and soluble Ag (as AgSO4) at 1, 10, and 100 mg Ag kg(-1) on the symbiosis between the legume Medicago truncatula and the nitrogen-fixing bacterium, Sinorhizobium melliloti in biosolids-amended soil. Nodulation frequency, nodule function, glutathione reductase production, and biomass were not significantly affected by any of the Ag treatments, even at 100 mg kg(-1), a concentration analogous to a worst-case scenario resulting from long-term, repeated biosolids amendments. Our results provide additional evidence that the disruption of the symbiosis between nitrogen-fixing bacteria and legumes in response to a mixture of ENMs in biosolids-amended soil reported previously may not be attributable to Ag ENMs or their transformation end-products. We anticipate these findings will provide clarity to regulators and industry regarding potential unintended consequences to terrestrial ecosystems resulting from of the use of Ag ENMs in consumer products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Diversity pattern of nitrogen fixing microbes in nodules of Trifolium arvense (L. at different initial stages of ecosystem development

    Directory of Open Access Journals (Sweden)

    M. Schloter

    2013-02-01

    Full Text Available Legumes can be considered as pioneer plants during ecosystem development, as they form a symbiosis with different nitrogen fixing rhizobia species, which enable the plants to grow on soils with low available nitrogen content. In this study we compared the abundance and diversity of nitrogen fixing microbes based on the functional marker gene nifH, which codes for a subunit of the Fe-protein of the dinitrogenase reductase, in nodules of different size classes of Trifolium arvense (L.. Additionally, carbon and nitrogen contents of the bulk soil and plant material were measured. Plants were harvested from different sites, reflecting 2 (2a and 5 (5a yr of ecosystem development, of an opencast lignite mining area in the south of Cottbus, Lower Lusatia (Germany where the artificial catchment "Chicken Creek" was constructed to study the development of terrestrial ecosystems. Plants from the 5a site revealed higher amounts of carbon and nitrogen, although nifH gene abundances in the nodules and carbon and nitrogen contents between the two soils did not differ significantly. Analysis of the nifH clone libraries showed a significant effect of the nodule size on the community composition of nitrogen fixing microbes. Medium sized nodules (2–5 mm contained a uniform community composed of Rhizobium leguminosarum bv. trifolii, whereas the small nodules (Rhizobium nifH gene sequences. Regarding the impact of the soil age on the community composition a clear distinction between the small and the medium nodules can be made. While clone libraries from the medium nodules were pretty similar at both soil ages, soil age had a significant effect on the community compositions of the small nodules, where the proportion of R. leguminosarum bv. trifolii increased with soil age.

  16. Production and release of selenocyanate by different green freshwater algae in environmental and laboratory samples.

    Science.gov (United States)

    LeBlanc, Kelly L; Smith, Matthew S; Wallschläger, Dirk

    2012-06-05

    In a previous study, selenocyanate was tentatively identified as a biotransformation product when green algae were exposed to environmentally relevant concentrations of selenate. In this follow-up study, we confirm conclusively the presence of selenocyanate in Chlorella vulgaris culture medium by electrospray mass spectrometry, based on selenium's known isotopic pattern. We also demonstrate that the observed phenomenon extends to other green algae (Chlorella kesslerii and Scenedesmus obliquus) and at least one species of blue-green algae (Synechococcus leopoliensis). Further laboratory experiments show that selenocyanate production by algae is enhanced by addition of nitrate, which appears to serve as a source of cyanide produced in the algae. Ultimately, this biotransformation process was confirmed in field experiments where trace amounts of selenocyanate (0.215 ± 0.010 ppb) were observed in a eutrophic, selenium-impacted river with massive algal blooms, which consisted of filamentous green algae (Cladophora genus) and blue-green algae (Anabaena genus). Selenocyanate abundance was low despite elevated selenium concentrations, apparently due to suppression of selenate uptake by sulfate, and insufficient nitrogen concentrations. Finally, trace levels of several other unidentified selenium-containing compounds were observed in these river water samples; preliminary suggestions for their identities include thioselenate and small organic Se species.

  17. Nitrogen-fixing bacteria with multiple plant growth-promoting activities enhance growth of tomato and red pepper.

    Science.gov (United States)

    Islam, Md Rashedul; Sultana, Tahera; Joe, M Melvin; Yim, Woojong; Cho, Jang-Cheon; Sa, Tongmin

    2013-12-01

    As a suitable alternative to chemical fertilizers, the application of plant growth-promoting rhizobacteria has been increasing in recent years due to their potential to be used as biofertilizers. In the present work, 13 nitrogen-fixing bacterial strains belonging to 11 different genera were tested for their PGP attributes. All of the strains were positive for 1-aminocyclopropane-1-carboxylate deaminase (ACCD), indole-3-acetic acid (IAA), salicylic acid, and ammonia production while negative for cellulase, pectinase, and hydrocyanic acid production. The strains Pseudomonas sp. RFNB3 and Serratia sp. RFNB14 were the most effective in solubilizing both tri-calcium phosphate and zinc oxide. In addition, all strains except Pseudomonas sp. RFNB3 were able to oxidize sulfur, and six strains were positive for siderophore synthesis. Each strain tested in this study possesses at least four PGP properties in addition to nitrogen fixation. Nine strains were selected based on their multiple PGP potential, particularly ACCD and IAA production, and evaluated for their effects on early growth of tomato and red pepper under gnotobiotic conditions. Bacterial inoculation considerably influenced root and shoot length, seedling vigor, and dry biomass of the two crop plants. Three strains that demonstrated substantial effects on plant performance were further selected for greenhouse trials with red pepper, and among them Pseudomonas sp. RFNB3 resulted in significantly higher plant height (26%) and dry biomass (28%) compared to control. The highest rate of nitrogen fixation, as determined by acetylene reduction assay, occurred in Novosphingobium sp. RFNB21 inoculated red pepper root (49.6 nM of ethylene/h/g of dry root) and rhizosphere soil (41.3 nM of ethylene/h/g of dry soil). Inoculation with nitrogen-fixing bacteria significantly increased chlorophyll content, and the uptake of different macro- and micro-nutrient contents enhancing also in red pepper shoots, in comparison with

  18. Effects of monosulfuron-ester on metabolic processes of nitrogen-fixing cyanobacteria Anabaena flos-aquae and Anabaena azotica

    OpenAIRE

    Shen, Jian Ying; Liao, Jin Zhi; Guo, Li Li; Su, Rui Fang

    2017-01-01

    Presence of the relatively new sulfonylurea herbicide monosulfuron-ester at 0.03?300?nmol/L affected the growth of two non-target nitrogen-fixing cyanobacteria (Anabaena flos-aquae and Anabaena azotica) and substantially inhibited in vitro Acetolactate synthase activity, with IC50 of 3.3 and 101.3?nmol/L for A. flos-aquae and A. azotica, respectively. Presenting in 30?300?nmol/L, it inhibited protein synthesis of the cyanobacteria with less amino acids produced as its concentration increased....

  19. Response of freshwater algae to water quality in Qinshan Lake within Taihu Watershed, China

    Science.gov (United States)

    Zhang, Jianying; Ni, Wanmin; Luo, Yang; Jan Stevenson, R.; Qi, Jiaguo

    Although frequent algal blooms in Taihu Lake in China have become major environmental problems and have drawn national and international attention, little is understood about the relationship between algal blooms and water quality. The goal of this study was to assess the growth and species responses of freshwater algae to variation in water quality in Qinshan Lake, located in headwaters of the Taihu watershed. Water samples were collected monthly from ten study sites in the Qinshan Lake and were analyzed for species distribution of freshwater algae and physiochemical parameters such as total nitrogen (TN), NH4+-N, NO3--N, total phosphorus (TP), chemical oxygen demand (COD Mn) and Chl-a. The results showed that average TN was 4.47 mg/L, with 92.2% of values greater than the TN standard set by the Chinese Environmental Protection Agency; average TP was 0.051 mg/L, with 37.9% of values above the TP national standard; and average trophic level index (TLI) was 53, the lower end of eutrophic condition. Average Chl-a concentration was 12.83 mg/m 3. Green algae and diatom far outweighed other freshwater algae and were dominant most time of the year, with the highest relative abundances of 96% and 99%, respectively. Blue-green algae, composed mainly toxic strains like Microcystis sp ., Nostoc sp. and Oscillatoria sp., became most dominant in the summer with the maximum relative abundance of 69%. The blue-green algae sank to the lake bottom to overwinter, and then dinoflagellates became the dominant species in the winter, with highest relative abundance of 89%. Analysis indicated that nutrients, especially control of ammonia and co-varying nutrients were the major restrictive factor of population growth of blue-green algae, suggesting that control in nutrient enrichments is the major preventive measure of algal blooms in Qinshan Lake.

  20. A new phenol oxidase produced during melanogenesis and encystment stage in the nitrogen-fixing soil bacterium Azotobacter chroococcum.

    Science.gov (United States)

    Herter, Susanne; Schmidt, Marlen; Thompson, Mark L; Mikolasch, Annett; Schauer, Frieder

    2011-05-01

    Laccases are copper-containing phenol oxidases that are commonly found in many types of plant, insect, fungi and bacteria. Whilst phenol oxidases have been well characterized in fungal species, laccase-type enzymes originating from bacteria have been much less well defined. Bacteria belonging to the family Azotobacteraceae share many morphological characteristics with strains already known to exhibit polyphenol and phenol oxidase activity; and hence the aim of this work was to identify and characterize a novel laccase from the isolated strain Azotobacter chroococcum SBUG 1484 in an attempt to provide further understanding of the roles such enzymes play in physiological development. Laccase activity was clearly observed through oxidation of 2,6-dimethoxyphenol, other typical substrates including: methoxy-monophenols, ortho- and para-diphenols, 4-hydroxyindole, and the non-phenolic compound para-phenylenediamine. A. chroococcum SBUG 1484 showed production of a cell-associated phenol oxidase when grown under nitrogen-fixing conditions, and was also observed when cells enter the melanogenic and encystment stages of growth. Catechol which is structurally related to melanin compounds was also released from Azotobacter cells into the surrounding culture medium during nitrogen-fixing growth. From our results we propose that a membrane-bound laccase plays an important role in the formation of melanin, which was monitored to correlate with progression of A. chroococcum SBUG 1484 cells into the encystment stage of growth.

  1. Effect of A Nitrogen-Fixing Actinorhizal Shrub on Herbaceous Vegetation in A Mixed Conifer Forest of Central Himalaya

    Directory of Open Access Journals (Sweden)

    Kiran Bargali

    2015-12-01

    Full Text Available In this study, we examined the effect of a nitrogen-fixing shrub Coriaria nepalensis Wall on herb species composition, diversity and biomass. The effect was measured in terms of species richness, diversity and biomass of herb species in three sites varying in Coriaria density viz. site 1 (low Coriaria density; 20 ha-1, site-2 (medium Coriaria density; 120 ha-1 and site-3 (high Coriaria density 190 ha-1. Species richness was minimum at Site-1 (16 species, and maximum at site-2 (27 species. G. aparine dominated site-1 and Arthraxon sp dominated site-2 and 3. The individual herb density ranged between 0.40 - 42.40 m-2, and total herb density ranged between 138- 170.4 m-2 and was maximum at site-2. Value for species richness (27 and Shannon Index (3.72 was highest for medium Coriaria density site and lowest for low Coriaria density site. Simpson Index ranged between 0.11 and 0.14 and was lowest for site-2(medium Coriaria density indicating that at this the dominance was shared by many species. Along the gradient of Coriaria density, maximum biomass was recorded at site-3 with highest Coriaria density and lowest at site-2 with medium Coriaria density. This may be due to the symbiotic nitrogen fixing ability of Coriaria that improve the habitat quality. The facilitative effect of C. nepalensis in terms of soil amelioration and herb growth can be used to regenerate degraded forest ecosystems.

  2. Daily dynamics of the number and activity of nitrogen-fixing bacteria in fallow and intensely cultivated soils

    Science.gov (United States)

    Emer, N. R.; Semenov, A. M.; Zelenev, V. V.; Zinyakova, N. B.; Kostina, N. V.; Golichenkov, M. V.

    2014-08-01

    The daily dynamics (during 33 days) of the number (colony-forming units (CFU)) of nitrogen-fixing bacteria and of the nitrogen-fixing activity (the acetylene method) were determined in a gray forest soil under a fallow land and under an intensely cultivated field. The daily dynamics of the CFUs determined on the nitrogen-free medium in the samples from both plots had wavelike patterns. The daily values of the actual and potential activities of nitrogen fixation in the samples from the fallow land plot and of the actual activity of nitrogen fixation in the samples from the intensely cultivated soil were low and close to the detection limit. The potential activity of nitrogen fixation in the intensely cultivated soil was significant and also had a wavelike pattern. The harmonic analysis of the daily dynamics of the CFUs and nitrogen fixation showed the statistically significant harmonics of these biological characteristics pointing to the objective and regular character of the wavelike dynamics. The revealed dynamics of the biological characteristics of the soils and the methods of their analysis are important in terms of the comparative study of the biological properties of different soils.

  3. Microscopic origin of the fast blue-green luminescence of chemically synthesized non-oxidized silicon quantum dots.

    Science.gov (United States)

    Dohnalová, Kateřina; Fučíková, Anna; Umesh, Chinnaswamy P; Humpolíčková, Jana; Paulusse, Jos M J; Valenta, Jan; Zuilhof, Han; Hof, Martin; Gregorkiewicz, Tom

    2012-10-22

    The microscopic origin of the bright nanosecond blue-green photoluminescence (PL), frequently reported for synthesized organically terminated Si quantum dots (Si-QDs), has not been fully resolved, hampering potential applications of this interesting material. Here a comprehensive study of the PL from alkyl-terminated Si-QDs of 2-3 nm size, prepared by wet chemical synthesis is reported. Results obtained on the ensemble and those from the single nano-object level are compared, and they provide conclusive evidence that efficient and tunable emission arises due to radiative recombination of electron-hole pairs confined in the Si-QDs. This understanding paves the way towards applications of chemical synthesis for the development of Si-QDs with tunable sizes and bandgaps. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Aesthetically Pleasing Conjugated Polymer: Fullerene Blends for Blue-Green Solar Cells Via Roll-to-Roll Processing

    DEFF Research Database (Denmark)

    Amb, Chad M.; Craig, Michael R.; Koldemir, Unsal

    2012-01-01

    as a thin-film deposition technique due its convenience. We report on the significant differences between the spin-coating of laboratory solar cells and slot-die coating of a blue-green colored, low bandgap polymer (PGREEN). This is one of the first demonstrations of slot-die-coated polymer solar cells OPVs...... not utilizing poly(3-hexylthiophene):(6,6)-phenyl-C61-butyric acid methyl ester (PCBM) blends as a light absorbing layer. Through synthetic optimization, we show that strict protocols are necessary to yield polymers which achieve consistent photovoltaic behavior. We fabricated spin-coated laboratory scale OPV......The practical application of organic photovoltaic (OPV) cells requires high throughput printing techniques in order to attain cells with an area large enough to provide useful amounts of power. However, in the laboratory screening of new materials for OPVs, spin-coating is used almost exclusively...

  5. The influence of bubble populations generated under windy conditions on the blue-green light transmission in the upper ocean: An exploratory approach

    Science.gov (United States)

    Wang, Chengan; Tan, Jianyu; Lai, Qingzhi

    2016-12-01

    The “blue-green window” in the ocean plays an important role in functions such as communication between vessels, underwater target identification, and remote sensing. In this study, the transmission process of blue-green light in the upper ocean is analyzed numerically using the Monte Carlo method. First, the effect of total number of photons on the numerical results is evaluated, and the most favorable number is chosen to ensure accuracy without excessive costs for calculation. Then, the physical and mathematical models are constructed. The rough sea surface is generated under windy conditions and the transmission signals are measured in the far field. Therefore, it can be conceptualized as a 1D slab with a rough boundary surface. Under windy conditions, these bubbles form layers that are horizontally homogeneous and decay exponentially with depth under the influence of gravity. The effects of bubble populations on the process of blue-green light transmission at different wind speeds, wavelengths, angle of incidence and chlorophyll-a concentrations are studied for both air-incident and water-incident cases. The results of this study indicate that the transmission process of blue-green light is significantly influenced by bubbles under high wind-speed conditions.

  6. Studies on utilization of nitrogen-fixing bacteria for saving energy; Chisso koteikin no katsuyo ni yoru sho energy no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Uozumi, T.; Koyama, R.; Horiuchi, M.; Hidaka, M.; Masaki, H. [The University of Tokyo, Tokyo (Japan); Shigematsu, T.; Inoue, A. [New Energy and Industrial Technology Development Organization, Tokyo, (Japan)

    1997-02-01

    This paper describes analysis and enhancement of nitrogen-fixing gene of rice root bacteria, such as Klebsiella oxytoca, Azospirillum lipoferumn and Sphingomonas paucimobilis, for realizing energy saving through conservation of nitrogenous fertilizers. For K. oxytoca, modified strain R-16 was developed, which can fix nitrogen effectively even in the presence of NH4{sup +}. Nitrogen-fixing ability of A. lipoferumn depends on the activity control by the modification of nitrogen-fixing enzyme as well as on the adjustment of transcription level by the transcription activating gene, nifA. The control gene relating to the above was analyzed by making clones. As a result, a modified strain TAl without the control by NH4{sup +} was developed. The R-16 and TAl strains were inoculated into rice sterile-cultured without nitrogen. Consequently, inoculated strains were settled in the root, which resulted in the increased vegetation weight of plant to two times heavier than that without inoculation. 9 refs.

  7. Requirement of Fra proteins for communication channels between cells in the filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120.

    Science.gov (United States)

    Omairi-Nasser, Amin; Mariscal, Vicente; Austin, Jotham R; Haselkorn, Robert

    2015-08-11

    The filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 differentiates specialized cells, heterocysts, that fix atmospheric nitrogen and transfer the fixed nitrogen to adjacent vegetative cells. Reciprocally, vegetative cells transfer fixed carbon to heterocysts. Several routes have been described for metabolite exchange within the filament, one of which involves communicating channels that penetrate the septum between adjacent cells. Several fra gene mutants were isolated 25 y ago on the basis of their phenotypes: inability to fix nitrogen and fragmentation of filaments upon transfer from N+ to N- media. Cryopreservation combined with electron tomography were used to investigate the role of three fra gene products in channel formation. FraC and FraG are clearly involved in channel formation, whereas FraD has a minor part. Additionally, FraG was located close to the cytoplasmic membrane and in the heterocyst neck, using immunogold labeling with antibody raised to the N-terminal domain of the FraG protein.

  8. Isolation and Identification of Phosphate Solubilizing and Nitrogen Fixing Bacteria from Soil in Wamena Biological Garden, Jayawijaya, Papua

    Directory of Open Access Journals (Sweden)

    SRI WIDAWATI

    2005-07-01

    Full Text Available A study was undertaken to investigate the occurrence of phosphate solubilizing bacteria (PSB and nitrogen-fixing bacteria (NFB from soil samples of Wamena Biological Garden (WbiG. Eleven soil samples were collected randomly to estimate microbial population which used plate count method. The result showed that the microbial population ranged from 5.0x103-7.5x106 cells of bacteria/gram of soil and 5.0x103-1.5x107 cells of bacteria/gram of soil for PSB and NFB respectively. There were 17 isolates which have been identified till genus and species. The isolated microorganism were identified as PSB i.e. Bacillus sp., B. pantothenticus, B. megatherium, Flavobacterium sp., F. breve, Klebsiella sp., K. aerogenes, Chromobacterium lividum, Enterobacter alvei, E. agglomerans, Pseudomonas sp., Proteus sp. and as NFB i.e. Azotobacter sp., A. chroococcum, A. paspalii, Rhizobium sp., and Azospirillum sp.

  9. Proteomic analysis reveals contrasting stress response to uranium in two nitrogen-fixing Anabaena strains, differentially tolerant to uranium.

    Science.gov (United States)

    Panda, Bandita; Basu, Bhakti; Acharya, Celin; Rajaram, Hema; Apte, Shree Kumar

    2017-01-01

    Two strains of the nitrogen-fixing cyanobacterium Anabaena, native to Indian paddy fields, displayed differential sensitivity to exposure to uranyl carbonate at neutral pH. Anabaena sp. strain PCC 7120 and Anabaena sp. strain L-31 displayed 50% reduction in survival (LD50 dose), following 3h exposure to 75μM and 200μM uranyl carbonate, respectively. Uranium responsive proteome alterations were visualized by 2D gel electrophoresis, followed by protein identification by MALDI-ToF mass spectrometry. The two strains displayed significant differences in levels of proteins associated with photosynthesis, carbon metabolism, and oxidative stress alleviation, commensurate with their uranium tolerance. Higher uranium tolerance of Anabaena sp. strain L-31 could be attributed to sustained photosynthesis and carbon metabolism and superior oxidative stress defense, as compared to the uranium sensitive Anabaena sp. strain PCC 7120.

  10. The effect of salt tolerant nitrogen fixing bacteria on the growth of paddy rice (Oryza sativa. L

    Directory of Open Access Journals (Sweden)

    Suliasih Suliasih

    2014-06-01

    Full Text Available Nitrogen fixing bacteria (Azospirillum and Azotobacter were isolated from coastal mangrove in Pulau seribu. The aims of the experiment was to find out isolates of nitrogen fixing bacteria which were tolerant to high salinity. The isolates can be used as a biofertilizer to support coastal agriculture.A total of 28 isolates (14 isolates of Azospirillum and 14 isolates of Azotobacter were tested their tolerance to salt by growing them in their respective media containing 1% 2% and 3 % NaCl,. Salt tolerant isolates obtained, then used as inoculants in paddy. The experiment laid out factorial based randomized complete block design which was comprised of 7 fertilizer treatments and 5 watering treatments with 5 replicates for each treatment at green house of Microbiology Division, Research Center of Biology, Indonesian Institute of Sciences. The first factor was fertilizer treatments 1. Compost + mixed bacteria (K1, 2. Control without inoculant , 3. Compost, 4. NPK, 5. Compost + NPK + mixed microbial, 6. Azotobacter isolates; 7. Azospirillum isolates. The second factor was watering treatments, plant was watered by : 1. Freshwater, 2. freshwater + sea water at mixture ratio 1:1, 3. Sea water, 4. sea water + 2% NaCl (20 g NaCl / l , 5. freshwater + 5% NaCl (50 g NaCl / l.The result showed that there were 9 isolates of Azospirillum and 4 isolates of Azotobacter which were tolerant to grow at media with 3% NaCl The green house experimental result revealed that the plants were treated with bacteria can survive up to the level of salinity 12.43 dS-1m.

  11. Abundance and diversity of nitrogen-fixing bacteria in rhizosphere and bulk paddy soil under different duration of organic management.

    Science.gov (United States)

    Shu, Wang; Pablo, Gonzalez Perez; Jun, Ye; Danfeng, Huang

    2012-02-01

    Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR) approaches were used to assess respectively the molecular diversity and quantity of the nifH gene sequences in rhizosphere and bulk paddy soil under conventional management and different duration of organic management (2, 3, 5, 9 years). The phylogenetic distribution of clones based on nifH gene sequence showed that taxonomic groups were consisted of Alphaproteobacteria (27.6%), Betaproteobacteria (24.1%) and Gammaproteobacteria (48.3%). Members of the order Rhizobiales and Pseudomonadales were prevalent among the dominant diazotrophs. When the quantity of the nifH gene sequences was determined by qPCR, 2.27 × 10(5) to 1.14 × 10(6) copies/g of soil were detected. Except for 2 years organically managed soil, nifH gene copy numbers in organic soil, both rhizosphere and bulk, were significantly higher than in CM soil. Moreover, nifH gene copy numbers in the organic rhizosphere soil (3, 5, 9 years) were significantly higher than in bulk soil. The abundance and diversity of nitrogen-fixing bacteria tended to increase with duration of organic management but the highest number of nifH gene copies was observed in the rhizosphere and bulk soil of 5 years organic management. In addition, analysis of variance and canonical correspondence analysis (CCA) showed that C/N, C and N were important factors influencing the abundance and community structure of nitrogen-fixing bacterial.

  12. Transfer of a plant chitinase gene into a nitrogen-fixing Azospirillum and study of its expression.

    Science.gov (United States)

    Jayaraj, Jayaraman; Muthukrishnan, Subbaratnam; Liang, George H

    2004-07-01

    Azospirillum is used extensively in rice and other cereal crops as a biofertilizer. There is a substantial opportunity to improve the efficiency of this bacterium through the transfer of genes of agricultural importance from other organisms. Chitinases are antifungal proteins, and expression of chitinase genes in Azospirillum would help to develop strains with potential antifungal activities. So far there are no reports about transfer of plant genes into Azospirillum and their expression. The present study was aimed at expressing an antifungal gene (a rice chitinase) of plant origin in Azospirillum brasilense. A rice chitinase cDNA (RC 7) that codes for a 35 kDa protein was subcloned into a broad host range plasmid pDSK519 under the control of LacZ promoter. The plasmid was mobilized into the nitrogen-fixing bacterium, Azospirillum brasilense strain SP51eFL1, through biparental mating. The conjugation frequency was in the range of 35-40 x 10(-6). The transconjugants grew in nitrogen-free media and fixed gaseous nitrogen in vitro. However, their growth and nitrogen-fixing ability were slightly less than those of the wild-type. Expression of the protein was demonstrated through western blotting of the total cell protein, which detected a 35 kDa band that was immuno-reactive to a barley chitinase antibody. The cell lysates also hydrolyzed various chitin substrates, which resulted in release of free sugars demonstrating the chitinase activity of transconjugants. The expressed protein also had antifungal activity as demonstrated by inhibition of growth of the plant pathogenic fungus, Rhizoctonia solani.

  13. Errors When Extracting Oil from Algae

    Science.gov (United States)

    Murphy, E.; Treat, R.; Ichiuji, T.

    2014-12-01

    Oil is in popular demand, but the worldwide amount of oil is decreasing and prices for it are steadily increasing. Leading scientists have been working to find a solution of attaining oil in an economically and environmentally friendly way. Researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) have determined that "a small mixture of algae and water can be turned into crude oil in less than an hour" (Sheehan, Duhahay, Benemann, Poessler). There are various ways of growing the algae, such as closed loop and open loop methods, as well as processes of extracting oil, such as hydrothermal liquefaction and the hexane-solvent method. Our objective was to grow the algae (C. reinhardtii) and extract oil from it using NaOH and HCl, because we had easy access to those specific chemicals. After two trials of attempted algae growth, we discovered that a bacteria was killing off the algae. This led us to further contemplation on how this dead algae and bacteria are affecting our environment, and the organisms within it. Eutrophication occurs when excess nutrients stimulate rapid growth of algae in an aquatic environment. This can clog waterways and create algal blooms in blue-green algae, as well as neurotoxic red tide phytoplankton. These microscopic algae die upon consumption of the nutrients in water and are degraded by bacteria. The bacteria respires and creates an acidic environment with the spontaneous conversion of carbon dioxide to carbonic acid in water. This process of degradation is exactly what occurred in our 250 mL flask. When the phytoplankton attacked our algae, it created a hypoxic environment, which eliminated any remaining amounts of oxygen, carbon dioxide, and nutrients in the water, resulting in a miniature dead zone. These dead zones can occur almost anywhere where there are algae and bacteria, such as the ocean, and make it extremely difficult for any organism to survive. This experiment helped us realize the

  14. Metal-enhanced fluorescence of graphene oxide by palladium nanoparticles in the blue-green part of the spectrum

    Science.gov (United States)

    Omidvar, A.; RashidianVaziri, M. R.; Jaleh, B.; Partovi Shabestari, N.; Noroozi, M.

    2016-11-01

    Graphene oxide (GO) has a wide fluorescence bandwidth, which makes it a prospective candidate for numerous applications. For many of these applications, the fluorescence yield of GO should be further increased. The sp2-hybridized carbons in GO confine the π-electrons. Radiative recombination of electron-hole pairs in such sp2 clusters is the source of fluorescence in this material. Palladium nanoparticles are good catalysts for sp2 bond formations. We report on the preparation of GO, palladium nanoparticles and their nanocomposites in two different solvents. It is shown that palladium nanoparticles can considerably enhance the intrinsic fluorescence of GO in the blue-green part of the visible light spectrum. Fluorescence enhancement has been attributed to the catalytic role of palladium nanoparticles in increasing the number of sp2 bonds of GO with the molecules of the surrounding media. It is shown that palladium nanoparticles could be the nanoparticle of choice for fluorescence enhancement of GO because of their catalytic role in sp2 bond formation.

  15. 16S ribosomal DNA characterization of nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril).

    Science.gov (United States)

    Magalhães Cruz, L; de Souza, E M; Weber, O B; Baldani, J I; Döbereiner, J; Pedrosa, F de O

    2001-05-01

    Nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril) were characterized by amplified 16S ribosomal DNA restriction analysis and 16S rRNA sequence analysis. Herbaspirillum seropedicae, Herbaspirillum rubrisubalbicans, Burkholderia brasilensis, and Burkholderia tropicalis were identified. Eight other types were placed in close proximity to these genera and other alpha and beta Proteobacteria.

  16. Ba3(P1−MnO4)2 : Blue/green inorganic materials based on tetrahedral Mn(V)

    Indian Academy of Sciences (India)

    Sourav Laha; Rohit Sharma; S V Bhat; M L P Reddy; J Gopalakrishnan; S Natarajan

    2011-10-01

    We describe a blue/green inorganic material, Ba3(P1−MnO4)2 (I) based on tetrahedral MnO$^{3-}_{4}$ :32 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for ≤ 0.25 and dark green for ≥ 0.50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO$^{3-}_{4}$ chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P–O/Mn–O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of . The material could serve as a nontoxic blue/green inorganic pigment.

  17. A second conserved GAF domain cysteine is required for the blue/green photoreversibility of cyanobacteriochrome Tlr0924 from Thermosynechococcus elongatus.

    Science.gov (United States)

    Rockwell, Nathan C.; Njuguna, Stephanie Lane; Roberts, Laurel; Castillo, Elenor; Parson, Victoria L.; Dwojak, Sunshine; Lagarias, J. Clark; Spiller, Susan C.

    2008-01-01

    Phytochromes are widely occurring red/far-red photoreceptors that utilize a linear tetrapyrrole (bilin) chromophore covalently bound within a knotted PAS-GAF domain pair. Cyanobacteria also contain more distant relatives of phytochromes that lack this knot, such as the phytochrome-related cyanobacteriochromes implicated to function as blue/green switchable photoreceptors. In this study, we characterize the cyanobacteriochrome Tlr0924 from the thermophilic cyanobacterium Thermosynechococcus elongatus. Full-length Tlr0924 exhibits blue/green photoconversion across a broad range of temperatures, including physiologically relevant temperatures for this organism. Spectroscopic characterization of Tlr0924 demonstrates that its green-absorbing state is in equilibrium with a labile, spectrally distinct blue-absorbing species. The photochemically generated blue-absorbing state is in equilibrium with another species absorbing at longer wavelengths, giving a total of 4 states. Cys499 is essential for this behavior, because mutagenesis of this residue results in red-absorbing mutant biliproteins. Characterization of the C499D mutant protein by absorbance and CD spectroscopy supports the conclusion that its bilin chromophore adopts a similar conformation to the red-light-absorbing Pr form of phytochrome. We propose a model photocycle in which Z/E photoisomerization of the 15/16 bond modulates formation of a reversible thioether linkage between Cys499 and C10 of the chromophore, providing the basis for the blue/green switching of cyanobacteriochromes. PMID:18549244

  18. Nitrogen-fixing Rhizobium-legume symbiosis: Are polyploidy and host peptide-governed symbiont differentiation general principles of endosymbiosis?

    Directory of Open Access Journals (Sweden)

    Gergely eMaróti

    2014-06-01

    Full Text Available The symbiosis between rhizobia soil bacteria and legumes is facultative and initiated by nitrogen starvation of the host plant. Exchange of signal molecules between the partners leads to the formation of root nodules where bacteria are converted to nitrogen-fixing bacteroids. In this mutualistic symbiosis, the bacteria provide nitrogen sources for plant growth in return for photosynthates from the host. Depending on the host plant the symbiotic fate of bacteria can either be reversible or irreversible. In Medicago plants the bacteria undergo a host-directed multistep differentiation process culminating in the formation of elongated and branched polyploid bacteria with definitive loss of cell division ability. The plant factors are nodule-specific symbiotic peptides. About 500 of them are cysteine-rich NCR peptides produced in the infected plant cells. NCRs are targeted to the endosymbionts and the concerted action of different sets of peptides governs different stages of endosymbiont maturation. This review focuses on symbiotic plant cell development and terminal bacteroid differentiation and demonstrates the crucial roles of symbiotic peptides by showing an example of multi-target mechanism exerted by one of these symbiotic peptides.

  19. Exopolysaccharide production is required for biofilm formation and plant colonization by the nitrogen-fixing endophyte Gluconacetobacter diazotrophicus.

    Science.gov (United States)

    Meneses, Carlos H S G; Rouws, Luc F M; Simoes-Araujo, Jean L; Vidal, Marcia S; Baldani, Jos I

    2011-12-01

    The genome of the endophytic diazotrophic bacterial species Gluconacetobacter diazotrophicus PAL5 (PAL5) revealed the presence of a gum gene cluster. In this study, the gumD gene homologue, which is predicted to be responsible for the first step in exopolysaccharide (EPS) production, was insertionally inactivated and the resultant mutant (MGD) was functionally studied. The mutant MGD presented normal growth and nitrogen (N(2)) fixation levels but did not produce EPS when grown on different carbon sources. MGD presented altered colony morphology on soft agar plates (0.3% agar) and was defective in biofilm formation on glass wool. Most interestingly, MGD was defective in rice root surface attachment and in root surface and endophytic colonization. Genetic complementation reverted all mutant phenotypes. Also, the addition of EPS purified from culture supernatants of the wild-type strain PAL5 to the mutant MGD was effective in partially restoring wild-type biofilm formation and plant colonization. These data provide strong evidence that the PAL5 gumD gene is involved in EPS biosynthesis and that EPS biosynthesis is required for biofilm formation and plant colonization. To our knowledge, this is the first report of a role of EPS in the endophytic colonization of graminaceous plants by a nitrogen-fixing bacterium.

  20. Hydrogen generation through indirect biophotolysis in batch cultures of the nonheterocystous nitrogen-fixing cyanobacterium Plectonema boryanum.

    Science.gov (United States)

    Huesemann, Michael H; Hausmann, Tom S; Carter, Blaine M; Gerschler, Jared J; Benemann, John R

    2010-09-01

    The nitrogen-fixing nonheterocystous cyanobacterium Plectonema boryanum was used as a model organism to study hydrogen generation by indirect biophotolysis in nitrogen-limited batch cultures that were continuously illuminated and sparged with argon/CO(2) to maintain anaerobiosis. The highest hydrogen-production rate (i.e., 0.18 mL/mg day or 7.3 micromol/mg day) was observed in cultures with an initial medium nitrate concentration of 1 mM at a light intensity of 100 micromol/m(2) s. The addition of photosystem II (PSII) inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) did not reduce hydrogen-production rates relative to unchallenged controls for 50 to 150 h, and intracellular glycogen concentrations decreased significantly during the hydrogen generation period. The insensitivity of the hydrogen-production process to DCMU is indicative of the fact that hydrogen was not derived from water splitting at PSII (i.e., direct biophotolysis) but rather from electrons provided by intracellular glycogen reserves (i.e., indirect biophotolysis). It was shown that hydrogen generation could be sustained for long time periods by subjecting the cultures to alternating cycles of aerobic, nitrogen-limited growth and anaerobic hydrogen production.

  1. Effect of shoot removal on remobilization of carbon and nitrogen during regrowth of nitrogen-fixing alfalfa.

    Science.gov (United States)

    Aranjuelo, Iker; Molero, Gemma; Erice, Gorka; Aldasoro, Joseba; Arrese-Igor, Cesar; Nogués, Salvador

    2015-01-01

    The contribution of carbon and nitrogen reserves to regrowth following shoot removal has been studied in the past. However, important gaps remain in understanding the effect of shoot cutting on nodule performance and its relevance during regrowth. In this study, isotopic labelling was conducted at root and canopy levels with both (15) N2 and (13) C-depleted CO2 on exclusively nitrogen-fixing alfalfa plants. As expected, our results indicate that the roots were the main sink organs before shoots were removed. Seven days after regrowth the carbon and nitrogen stored in the roots was invested in shoot biomass formation and partitioned to the nodules. The large depletion in nodule carbohydrate availability suggests that root-derived carbon compounds were delivered towards nodules in order to sustain respiratory activity. In addition to the limited carbohydrate availability, the upregulation of nodule peroxidases showed that oxidative stress was also involved during poor nodule performance. Fourteen days after cutting, and as a consequence of the stimulated photosynthetic and N2 -fixing machinery, availability of Cnew and Nnew strongly diminished in the plants due to their replacement by C and N assimilated during the post-labelling period. In summary, our study indicated that during the first week of regrowth, root-derived C and N remobilization did not overcome C- and N-limitation in nodules and leaves. However, 14 days after cutting, leaf and nodule performance were re-established.

  2. Biodiversity, abundance, and activity of nitrogen-fixing bacteria during primary succession on a copper mine tailings.

    Science.gov (United States)

    Huang, Li-Nan; Tang, Feng-Zao; Song, Yong-Sheng; Wan, Cai-Yun; Wang, Sheng-Long; Liu, Wei-Qiu; Shu, Wen-Sheng

    2011-12-01

    Microorganisms are important in soil development, inputs and biogeochemical cycling of nutrients and organic matter during early stages of ecosystem development, but little is known about their diversity, distribution, and function in relation to the chemical and physical changes associated with the progress of succession. In this study, we characterized the community structure and activity of nitrogen-fixing microbes during primary succession on a copper tailings. Terminal fragment length polymorphism (T-RFLP) and clone sequencing of nifH genes indicated that different N(2) -fixing communities developed under primary succession. Phylogenetic analysis revealed a diversity of nifH sequences that were mostly novel, and many of these could be assigned to the taxonomic divisions Proteobacteria, Cyanobacteria, and Firmicutes. Members of the Cyanobacteria, mostly affiliated with Nostocales or not closely related to any known organisms, were detected exclusively in the biological soil crusts and represented a substantial fraction of the respective diazotrophic communities. Quantitative PCR (and statistical analyses) revealed that, overall, copy number of nifH sequences increased with progressing succession and correlated with changes in physiochemical properties (including elementary elements such as carbon and nitrogen) and the recorded nitrogenase activities of the tailings. Our study provides an initial insight into the biodiversity and community structure evolution of N(2) -fixing microorganisms in ecological succession of mine tailings. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  3. Characterization of nitrogen-fixing moderate halophilic cyanobacteria isolated from saline soils of Songnen Plain in China

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Yujie Feng

    2008-01-01

    Twenty out of 200 isolates of cyanobacteria mainly from saline soils of Songnen Plain of China were successfully grown on BG11 N-free medium. The nitrogen-fixing activity was then demonstrated for the 20 isolates in modified BG11 medium using the acetylene reduction assay. All of them possessed appreciable nitrogenase activity (acetylene reduction) under non-saline conditions; however, at 5% NaCl only 60% of the isolates exhibited a high rate of this activity and 25% were completely negative under these conditions. The cyanobacteria isolates grew well in BG11 medium; nevertheless, growth of the majority of isolates was reduced by about 25-85% in the same medium containing 5% NaCl. Cellulolytic activity was detected in 50% of the 20 strains, amylolytic in 45%, and pectinolytic in 10% of the isolates. The cyanobacteria isolates showed also enzymatic activity under saline conditions (6%). The preliminary identification indicated that seven isolates were Nostoc, two were Microcystis, four were Oscillatoria, six were Anabaena, and one isolate was Synechococcus.

  4. Diversity of nitrogen-fixing bacteria associated with switchgrass in the native tallgrass prairie of northern Oklahoma.

    Science.gov (United States)

    Bahulikar, Rahul A; Torres-Jerez, Ivone; Worley, Eric; Craven, Kelly; Udvardi, Michael K

    2014-09-01

    Switchgrass (Panicum virgatum L.) is a perennial C4 grass native to North America that is being developed as a feedstock for cellulosic ethanol production. Industrial nitrogen fertilizers enhance switchgrass biomass production but add to production and environmental costs. A potential sustainable alternative source of nitrogen is biological nitrogen fixation. As a step in this direction, we studied the diversity of nitrogen-fixing bacteria (NFB) associated with native switchgrass plants from the tallgrass prairie of northern Oklahoma (United States), using a culture-independent approach. DNA sequences from the nitrogenase structural gene, nifH, revealed over 20 putative diazotrophs from the alpha-, beta-, delta-, and gammaproteobacteria and the firmicutes associated with roots and shoots of switchgrass. Alphaproteobacteria, especially rhizobia, predominated. Sequences derived from nifH RNA indicated expression of this gene in several bacteria of the alpha-, beta-, delta-, and gammaproteobacterial groups associated with roots. Prominent among these were Rhizobium and Methylobacterium species of the alphaproteobacteria, Burkholderia and Azoarcus species of the betaproteobacteria, and Desulfuromonas and Geobacter species of the deltaproteobacteria. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  5. Field performance of new cowpea cultivars inoculated with efficient nitrogen-fixing rhizobial strains in the Brazilian Semiarid

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Nunes Marinho

    2014-05-01

    Full Text Available The objective of this work was to evaluate the contribution of efficient nitrogen-fixing rhizobial strains to grain yield of new cowpea cultivars, indicated for cultivation in the Brazilian Semiarid region, in the sub-medium of the São Francisco River Valley. Two experiments were set up at the irrigated perimeters of Mandacaru (Juazeiro, state of Bahia and Bebedouro (Petrolina, state of Pernambuco. The treatments consisted of single inoculation of five rhizobial strains - BR 3267, BR 3262, INPA 03-11B, UFLA 03-84 (Bradyrhizobium sp., and BR 3299T (Microvirga vignae -, besides a treatment with nitrogen and a control without inoculation or N application. The following cowpea cultivars were evaluated: BRS Pujante, BRS Tapaihum, BRS Carijó, and BRS Acauã. A randomized complete block design, with four replicates, was used. Inoculated plants showed similar grain yield to the one observed with plants fertilized with 80 kg ha-1 N. The cultivars BRS Tapaihum and BRS Pujante stood out in grain yield and protein contents when inoculated, showing their potential for cultivation in the sub-medium of the São Francisco River Valley.

  6. Morphological, biochemical and molecular characterization of twelve nitrogen-fixing bacteria and their response to various zinc concentration.

    Science.gov (United States)

    Dadook, Mohammad; Mehrabian, Sedigheh; Salehi, Mitra; Irian, Saeed

    2014-04-01

    Zinc is an essential micronutrient used in the form of zinc sulfate in fertilizers in the agriculture production system. Nitrogen-fixing microorganisms are also of considerable value in promoting soil fertility. This study aimed to investigate the degree of sensitivity to varying concentrations of zinc, in the form of ZnSO4, in different strains of Azotobacter chroococcum in a laboratory environment. To isolate A. chroococcum strains, soil samples were collected from wheat, corn and asparagus rhizospheres and cultured in media lacking nitrogen at 30˚C for 48 hours. Strains were identified based on morphological and biochemical characteristics. The presence of the nitrogenase enzyme system was confirmed by testing for the presence of the nifH gene using PCR analysis. The minimum inhibitory concentration (MIC) and optimal zinc concentration for the growth of each strain was determined. A total of 12 bacterial strains were isolated from six different soil samples. A. chroococcum strains were morphologically and biochemically characterized. The presence of the nifH gene was confirmed in all the strains. MIC and the optimal zinc concentration for bacterial growth were 50 ppm and 20 ppm, respectively. It was concluded that increasing the concentration of zinc in the agricultural soil is harmful to beneficial microorganisms and reduces the soil fertility. A 20-ppm zinc concentration in soil is suggested to be optimal.

  7. [Pharmacology and toxicology of Spirulina alga].

    Science.gov (United States)

    Chamorro, G; Salazar, M; Favila, L; Bourges, H

    1996-01-01

    Spirulina, a unicellular filamentous blue-green alga has been consumed by man since ancient times in Mexico and central Africa. It is currently grown in many countries by synthetic methods. Initially the interest in Spirulina was on its nutritive value: it was found almost equal to other plant proteins. More recently, some preclinical testing suggests it has several therapeutic properties such as hypocholesterolemic, immunological, antiviral and antimutagenic. This has led to more detailed evaluations such as nucleic acid content and presence of toxic metals, biogenic toxins and organic chemicals: they have shown absence or presence at tolerable levels according to the recommendations of international regulatory agencies. In animal experiments for acute, subchronic and chronic toxicity, reproduction, mutagenicity, and teratogenicity the algae did not cause body or organ toxicity. In all instances, the Spirulina administered to the animals were at much higher amounts than those expected for human consumption. On the other hand there is scant information of the effects of the algae in humans. This area needs more research.

  8. GROWTH-REGULATORY ACTIVITY OF THE ALGAE EXTRACT

    Directory of Open Access Journals (Sweden)

    О. V. Кyrychenkо

    2013-10-01

    Full Text Available The growth-regulatory activity of the complex algae extract from Spirogira sp. at pre-so wing treatment of soybean seeds was studied in green-house and field experiments. It was shown that phytoextract has stimulated seeds germination on 12%, plants growth on 11–37%, soybean productivity increased on 6–27% as well as activated the development and functional ability of rhizospheric nitrogen-fixing microorganisms. The quantity of oligoazotrophes increased in 1,5–6,3 times, nitrogenase activity in 1,5–1,7 times. The possibility aspects of growth-regulatory activity of the algae extract in both plants and rhizospheric microorganisms is under discussion. Our results have confirmed the perspectives of practical use of the biological activity substances from the algae at soybean growing in order to increase plants productivity and improve microbiological indexes of soil.

  9. Aesthetically pleasing conjugated polymer:fullerene blends for blue-green solar cells via roll-to-roll processing.

    Science.gov (United States)

    Amb, Chad M; Craig, Michael R; Koldemir, Unsal; Subbiah, Jegadesan; Choudhury, Kaushik Roy; Gevorgyan, Suren A; Jørgensen, Mikkel; Krebs, Frederik C; So, Franky; Reynolds, John R

    2012-03-01

    The practical application of organic photovoltaic (OPV) cells requires high throughput printing techniques in order to attain cells with an area large enough to provide useful amounts of power. However, in the laboratory screening of new materials for OPVs, spin-coating is used almost exclusively as a thin-film deposition technique due its convenience. We report on the significant differences between the spin-coating of laboratory solar cells and slot-die coating of a blue-green colored, low bandgap polymer (PGREEN). This is one of the first demonstrations of slot-die-coated polymer solar cells OPVs not utilizing poly(3-hexylthiophene):(6,6)-phenyl-C(61)-butyric acid methyl ester (PCBM) blends as a light absorbing layer. Through synthetic optimization, we show that strict protocols are necessary to yield polymers which achieve consistent photovoltaic behavior. We fabricated spin-coated laboratory scale OPV devices with PGREEN: PCBM blends as active light absorbing layers, and compare performance to slot die-coated individual solar cells, and slot-die-coated solar modules consisting of many cells connected in series. We find that the optimum ratio of polymer to PCBM varies significantly when changing from spin-coating of thinner active layer films to slot-die coating, which requires somewhat thicker films. We also demonstrate the detrimental impacts on power conversion efficiency of high series resistance imparted by large electrodes, illustrating the need for higher conductivity contacts, transparent electrodes, and high mobility active layer materials for large-area solar cell modules.

  10. Color discrimination in halobacteria: spectroscopic characterization of a second sensory receptor covering the blue-green region of the spectrum.

    Science.gov (United States)

    Wolff, E K; Bogomolni, R A; Scherrer, P; Hess, B; Stoeckenius, W

    1986-10-01

    Halobacterium halobium is attracted by green and red light and repelled by blue-green and shorter wavelength light. a photochromic, rhodopsin-like protein in the cell membrane, sensory rhodopsin sR587, has been identified as the receptor for the long-wavelength and near-UV stimuli. Discrepancies between the action spectrum for the repellent effect of blue light and the absorption spectrum of sR587 and its photocycle intermediate S373 strongly suggest the existence of an additional photoreceptor for the blue region of the spectrum. Transient light-induced absorbance changes in intact cells and cell membranes show, in addition to sR587, the presence of a second photoactive pigment with maximal absorption near 480 nm. It undergoes a cyclic photoreaction with a half-time of 150 msec. One intermediate state with maximal absorption near 360 nm has been resolved. The spectral properties of the new pigment are consistent with a function as the postulated photoreceptor for the repellent effect of blue light. The phototactic reactions and both pigments are absent when retinal synthesis is blocked; both can be restored by the addition of retinal. These results confirm and extend similar observations by Takahashi et al. [Takahashi, T., Tomioka, H., Kamo, N. & Kobatake, Y. (1985) FEMS Microbiol. Lett. 28, 161-164]. The archaeobacterium H. halobium thus uses two different mechanisms for color discrimination; it uses two rhodopsin-like receptors with different spectral sensitivities and also the photochromicity of at least one of these receptors to distinguish between three regions covering the visible and near-UV spectrum.

  11. Characterization of nitrogen-fixing bacteria from a temperate saltmarsh lagoon, including isolates that produce ethane from acetylene.

    Science.gov (United States)

    Tibbles, B J; Rawlings, D E

    1994-01-01

    Nitrogen-fixing bacteria were isolated from sediments and water of a saltmarsh lagoon on the west coast of South Africa, and characterized according to factors that regulate nitrogen fixation in the marine environment. The majority of isolates were assigned to the Photobacterium or Vibrio genera on the basis of physiological and biochemical characteristics. One isolate was further assigned to the species Vibrio diazotrophicus. Carbohydrate utilization by each diazotrophic isolate was examined. Abilities of the isolates to utilize a range of mono-, di-, and polysaccharides largely reflected the predicted availability of organic carbon and energy in the lagoon, except that chitin was not utilized. Biochemical tests on the utilization of combined nitrogen showed that one isolate could utilize nitrate, and that this strain was susceptible to full repression of nitrogenase activity by 10mM nitrate. Urease activity was not detected in any of the isolates. In the absence of molybdenum two of the isolates, a Photobacterium spp. and V. diazotrophicus, reduced acetylene to ethylene and ethane, a property frequently associated with the activity of alternative nitrogenases. Addition of 25µM molybdenum inhibited ethane production by V. diazotrophicus, but stimulated ethylene and ethane production by the Photobacterium isolate. Addition of 28µM vanadium did not appear to regulate ethane production by either strain. Assays of nitrogenase activity in sediments from which some isolates were obtained indicated that molybdenum was not limiting nitrogenase activity at naturally-occurring concentrations. Southern hybridizations of the chromosomes of these strains with the anfH and vnfH genes of Azotobacter vinelandii and the nifH gene of Klebsiella pneumoniae indicated the presence of only one nitrogenase in these isolates.

  12. Vibrio oceanisediminis sp. nov., a nitrogen-fixing bacterium isolated from an artificial oil-spill marine sediment.

    Science.gov (United States)

    Kang, Sang Rim; Srinivasan, Sathiyaraj; Lee, Sang-Seob

    2015-10-01

    A Gram-staining-negative, halophilic, facultatively anaerobic, motile, rod-shaped and nitrogen-fixing bacterium, designated strain S37T, was isolated from an artificial oil-spill sediment sample from the coast of Taean, South Korea. Cells grew at 10-37 °C and pH 5.0-9.0, with optimal growth at 28 °C and pH 6.0-8.0. Growth was observed with 1-9 % (w/v) NaCl in marine broth, with optimal growth with 3-5 % NaCl, but no growth was observed in the absence of NaCl. According to the results of 16S rRNA gene sequence analysis, strain S37T represents a member of the genus Vibrio of the class Gammaproteobacteria and forms a clade with Vibrio plantisponsor MSSRF60T (97.38 %), Vibrio diazotrophicus ATCC 33466T (97.31 %), Vibrio aestuarianus ATCC 35048T (97.07 %) Vibrio areninigrae J74T (96.76 %) and Vibrio hispanicus LMG 13240T (96.76 %). The major fatty acids were C16 : 0, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. The DNA G+C content was 41.9 %. The DNA-DNA hybridization analysis results showed a 30.2 % association value with the closely related type strain V. plantisponsor DSM 21026T. On the basis of phenotypic and chemotaxonomic characteristics, strain S37T represents a novel species of the genus Vibrio, for which the name Vibrio oceanisediminis sp. nov., is proposed with the type strain S37T ( = KEMB 2255-005T = JCM 30409T).

  13. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    Directory of Open Access Journals (Sweden)

    Diego Javier Jiménez

    2011-09-01

    Full Text Available With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-Sucrose agar obtaining a recovery of 40%. Twenty four isolates were evaluated for colony and cellular morphology, pigment production and metabolic activities. Molecular characterization was carried out using amplified ribosomal DNA restriction analysis (ARDRA. After digestion of 16S rDNA Y1-Y3 PCR products (1487pb with AluI, HpaII and RsaI endonucleases, a polymorphism of 16% was obtained. Cluster analysis showed three main groups based on DNA fingerprints. Comparison between ribotypes generated by isolates and in silico restriction of 16S rDNA partial sequences with same restriction enzymes was done with Gen Workbench v.2.2.4 software. Nevertheless, Y1-Y2 PCR products were analysed using BLASTn. Isolate C5T from tomato (Lycopersicon esculentum grown soils presented the same in silico restriction patterns with A. chroococcum (AY353708 and 99% of similarity with the same sequence. Isolate C5CO from cauliflower (Brassica oleracea var. botrytis grown soils showed black pigmentation in Ashby-Benzoate agar and high similarity (91% with A. nigricans (AB175651 sequence. In this work we demonstrated the utility of molecular techniques and bioinformatics tools as a support to conventional techniques in characterization of the genus Azotobacter from vegetable-grown soils.

  14. A genome-wide survey of sRNAs in the symbiotic nitrogen-fixing alpha-proteobacterium Sinorhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Jänicke Sebastian

    2010-04-01

    Full Text Available Abstract Background Small untranslated RNAs (sRNAs are widespread regulators of gene expression in bacteria. This study reports on a comprehensive screen for sRNAs in the symbiotic nitrogen-fixing alpha-proteobacterium Sinorhizobium meliloti applying deep sequencing of cDNAs and microarray hybridizations. Results A total of 1,125 sRNA candidates that were classified as trans-encoded sRNAs (173, cis-encoded antisense sRNAs (117, mRNA leader transcripts (379, and sense sRNAs overlapping coding regions (456 were identified in a size range of 50 to 348 nucleotides. Among these were transcripts corresponding to 82 previously reported sRNA candidates. Enrichment for RNAs with primary 5'-ends prior to sequencing of cDNAs suggested transcriptional start sites corresponding to 466 predicted sRNA regions. The consensus σ70 promoter motif CTTGAC-N17-CTATAT was found upstream of 101 sRNA candidates. Expression patterns derived from microarray hybridizations provided further information on conditions of expression of a number of sRNA candidates. Furthermore, GenBank, EMBL, DDBJ, PDB, and Rfam databases were searched for homologs of the sRNA candidates identified in this study. Searching Rfam family models with over 1,000 sRNA candidates, re-discovered only those sequences from S. meliloti already known and stored in Rfam, whereas BLAST searches suggested a number of homologs in related alpha-proteobacteria. Conclusions The screening data suggests that in S. meliloti about 3% of the genes encode trans-encoded sRNAs and about 2% antisense transcripts. Thus, this first comprehensive screen for sRNAs applying deep sequencing in an alpha-proteobacterium shows that sRNAs also occur in high number in this group of bacteria.

  15. The Independent Acquisition of Plant Root Nitrogen-Fixing Symbiosis in Fabids Recruited the Same Genetic Pathway for Nodule Organogenesis

    Science.gov (United States)

    Svistoonoff, Sergio; Benabdoun, Faiza Meriem; Nambiar-Veetil, Mathish; Imanishi, Leandro; Vaissayre, Virginie; Cesari, Stella; Diagne, Nathalie; Hocher, Valérie; de Billy, Françoise; Bonneau, Jocelyne; Wall, Luis; Ykhlef, Nadia; Rosenberg, Charles; Bogusz, Didier; Franche, Claudine; Gherbi, Hassen

    2013-01-01

    Only species belonging to the Fabid clade, limited to four classes and ten families of Angiosperms, are able to form nitrogen-fixing root nodule symbioses (RNS) with soil bacteria. This concerns plants of the legume family (Fabaceae) and Parasponia (Cannabaceae) associated with the Gram-negative proteobacteria collectively called rhizobia and actinorhizal plants associated with the Gram-positive actinomycetes of the genus Frankia. Calcium and calmodulin-dependent protein kinase (CCaMK) is a key component of the common signaling pathway leading to both rhizobial and arbuscular mycorrhizal symbioses (AM) and plays a central role in cross-signaling between root nodule organogenesis and infection processes. Here, we show that CCaMK is also needed for successful actinorhiza formation and interaction with AM fungi in the actinorhizal tree Casuarina glauca and is also able to restore both nodulation and AM symbioses in a Medicago truncatula ccamk mutant. Besides, we expressed auto-active CgCCaMK lacking the auto-inhibitory/CaM domain in two actinorhizal species: C. glauca (Casuarinaceae), which develops an intracellular infection pathway, and Discaria trinervis (Rhamnaceae) which is characterized by an ancestral intercellular infection mechanism. In both species, we found induction of nodulation independent of Frankia similar to response to the activation of CCaMK in the rhizobia-legume symbiosis and conclude that the regulation of actinorhiza organogenesis is conserved regardless of the infection mode. It has been suggested that rhizobial and actinorhizal symbioses originated from a common ancestor with several independent evolutionary origins. Our findings are consistent with the recruitment of a similar genetic pathway governing rhizobial and Frankia nodule organogenesis. PMID:23741336

  16. The independent acquisition of plant root nitrogen-fixing symbiosis in Fabids recruited the same genetic pathway for nodule organogenesis.

    Directory of Open Access Journals (Sweden)

    Sergio Svistoonoff

    Full Text Available Only species belonging to the Fabid clade, limited to four classes and ten families of Angiosperms, are able to form nitrogen-fixing root nodule symbioses (RNS with soil bacteria. This concerns plants of the legume family (Fabaceae and Parasponia (Cannabaceae associated with the Gram-negative proteobacteria collectively called rhizobia and actinorhizal plants associated with the Gram-positive actinomycetes of the genus Frankia. Calcium and calmodulin-dependent protein kinase (CCaMK is a key component of the common signaling pathway leading to both rhizobial and arbuscular mycorrhizal symbioses (AM and plays a central role in cross-signaling between root nodule organogenesis and infection processes. Here, we show that CCaMK is also needed for successful actinorhiza formation and interaction with AM fungi in the actinorhizal tree Casuarina glauca and is also able to restore both nodulation and AM symbioses in a Medicago truncatula ccamk mutant. Besides, we expressed auto-active CgCCaMK lacking the auto-inhibitory/CaM domain in two actinorhizal species: C. glauca (Casuarinaceae, which develops an intracellular infection pathway, and Discaria trinervis (Rhamnaceae which is characterized by an ancestral intercellular infection mechanism. In both species, we found induction of nodulation independent of Frankia similar to response to the activation of CCaMK in the rhizobia-legume symbiosis and conclude that the regulation of actinorhiza organogenesis is conserved regardless of the infection mode. It has been suggested that rhizobial and actinorhizal symbioses originated from a common ancestor with several independent evolutionary origins. Our findings are consistent with the recruitment of a similar genetic pathway governing rhizobial and Frankia nodule organogenesis.

  17. Effects of Salinity on Leaf Spectral Reflectance and Biochemical Parameters of Nitrogen Fixing Soybean Plants (Glycine max L.)

    Science.gov (United States)

    Krezhova, Dora D.; Kirova, Elisaveta B.; Yanev, Tony K.; Iliev, Ilko Ts.

    2010-01-01

    Measurements of physiology and hyperspectral leaf reflectance were used to detect salinity stress in nitrogen fixing soybean plants. Seedlings were inoculated with suspension of Bradyrhizobium japonicum strain 273. Salinity was performed at the stage of 2nd-4th trifoliate expanded leaves by adding of NaCl in the nutrient solution of Helrigel in concentrations 40 mM and 80 mM. A comparative analysis was performed between the changes in the biochemical parameters - stress markers (phenols, proline, malondialdehyde, thiol groups), chlorophyll a and b, hydrogen peroxide, and leaf spectral reflectance in the spectral range 450-850 nm. The spectral measurements were carried out by an USB2000 spectrometer. The reflectance data of the control and treated plants in the red, green, red-edge and the near infrared ranges of the spectrum were subjected to statistical analysis. Statistically significant differences were found through the Student's t-criterion at the two NaCl concentrations in all of the ranges examined with the exception of the near infrared range at 40 mM NaCl concentration. Similar results were obtained through linear discriminant analysis. The tents of the phenols, malondialdehyde and chlorophyll a and b were found to decrease at both salinity treatments. In the spectral data this effect is manifested by decrease of the reflectance values in the green and red ranges. The contents of proline, hydrogen peroxide and thiol groups rose with the NaCl concentration increase. At 80 mM NaCl concentration the values of these markers showed a considerable increase giving evidence that the soybean plants were stressed in comparison with the control. This finding is in agreement with the results from the spectral reflectance analysis.

  18. Characterization of two naturally truncated, Ssb-like proteins from the nitrogen-fixing cyanobacterium, Anabaena sp. PCC7120.

    Science.gov (United States)

    Kirti, Anurag; Rajaram, Hema; Apte, Shree Kumar

    2013-11-01

    Single-stranded (ss) DNA-binding (Ssb) proteins are vital for all DNA metabolic processes and are characterized by an N-terminal OB-fold followed by P/G-rich spacer region and a C-terminal tail. In the genome of the heterocystous, nitrogen-fixing cyanobacterium, Anabaena sp. strain PCC 7120, two genes alr0088 and alr7579 are annotated as ssb, but the corresponding proteins have only the N-terminal OB-fold and no P/G-rich region or acidic tail, thereby rendering them unable to interact with genome maintenance proteins. Both the proteins were expressed under normal growth conditions in Anabaena PCC7120 and regulated differentially under abiotic stresses which induce DNA damage, indicating that these are functional genes. Constitutive overexpression of Alr0088 in Anabaena enhanced the tolerance to DNA-damaging stresses which caused formation of DNA adducts such as UV and MitomycinC, but significantly decreased the tolerance to γ-irradiation, which causes single- and double-stranded DNA breaks. On the other hand, overexpression of Alr7579 had no significant effect on normal growth or stress tolerance of Anabaena. Thus, of the two truncated Ssb-like proteins, Alr0088 may be involved in protection of ssDNA from damage, but due to the absence of acidic tail, it may not aid in repair of damaged DNA. These two proteins are present across cyanobacterial genera and unique to them. These initial studies pave the way to the understanding of DNA repair in cyanobacteria, which is not very well documented.

  19. Diversity and activity of free-living nitrogen-fixing bacteria and total bacteria in organic and conventionally managed soils.

    Science.gov (United States)

    Orr, Caroline H; James, Angela; Leifert, Carlo; Cooper, Julia M; Cummings, Stephen P

    2011-02-01

    Agricultural soils are heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, the molecular ecology of the total bacterial and free-living nitrogen-fixing communities in soils from the Nafferton Factorial Systems Comparison (NFSC) study in northeast England were examined. The field experiment was factorial in design, with organic versus conventional crop rotation, crop protection, and fertility management factors. Soils were sampled on three dates (March, June, and September) in 2007. Total RNA was extracted from all soil samples and reverse transcribed. Denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) were used to analyze nifH and 16S rRNA genes in order to study free-living diazotrophs and the total bacterial community, respectively. Crop rotation was shown to have a significant effect on total bacterial diversity (and that of free-living N fixers) (P ≤ 0.001). On all three dates, nifH activity was higher in the conventional crop rotation. In contrast, qPCR analysis of free-living N fixers indicated significantly higher levels of activity in conventionally fertilized plots in June (P = 0.0324) and in plots with organic crop protection in September (P = 0.0143). To our knowledge, the effects of organic and conventional farming systems on free-living diazotrophs have never been studied. An increased understanding of the impacts of management practices on free-living N fixers could allow modifications in soil management practices to optimize the activity of these organisms.

  20. Efficient nitrogen-fixing Rhizobium strains isolated from amazonian soils are highly tolerant to acidity and aluminium.

    Science.gov (United States)

    Avelar Ferreira, Paulo Ademar; Bomfeti, Cleide Aparecida; Lima Soares, Bruno; de Souza Moreira, Fatima Maria

    2012-05-01

    One of the most cultivated and consumed vegetables in Brazil is the common bean, Phaseolus vulgaris L. The symbiosis of this plant species with nitrogen-fixing bacteria that are adapted to the stresses commonly found in tropical soils can increase production. The aim of this study was to evaluate the symbiotic effectiveness of bacterial strains from soils under different land uses in the Amazon region. Further, rhizobia tolerance to acidity and aluminium and the involvement of some possible physiological mechanisms of such tolerance were also investigated. In assessing the efficiency of biological nitrogen fixation, inoculation with strains UFLA04-195, UFLA04-173 and UFLA04-202, belonging to the genus Rhizobium, resulted in greater plant growth, higher shoot nitrogen content and good nodulation compared to the inoculation with the strain CIAT 899 (R. tropici), and to the mineral nitrogen control or Burkholderia fungorum strains that nodulated or not bean plants. These efficient strains grew better at pH 5.0 than at pH 6.0 or pH 6.9; they also tolerated up to 1 mmol l(-1) of Al(3+) and showed an increased production of exopolysaccharides where the growing rates were less (pH 6.0 and pH 6.9). With respect to aluminium, the highest production of EPS produced greater tolerance to this element. Taken together, these results indicate that the strains evaluated in this study were tolerant to acidity and aluminium; they appeared to have developed resistance mechanisms such as EPS production and a resistant cell outer membrane (indicated by resistance to polymyxin and methyl violet). As these strains also gave increased yields of the host species, further studies on whether to recommend these strains as inoculants are already underway.

  1. Effect of succinate on phosphate solubilization in nitrogen fixing bacteria harbouring chick pea and their effect on plant growth.

    Science.gov (United States)

    Iyer, Bhagya; Rajput, Mahendrapal Singh; Rajkumar, Shalini

    2017-09-01

    Diverse nitrogen fixing bacteria harbouring chick pea rhizosphere and root nodules were tested for multiple plant growth promoting traits like tricalcium phosphate (TCP) and rock phosphate (RP) solubilization, production of ammonia, indole 3-acetic acid, chitinase, phytase and alkaline phosphatase. Isolates belonged to diverse genus like Enterobacter, Acinetobacter, Erwinia, Pseudomonas, Rhizobium, Sinorhizobium, Ensifer, Klebsiella, etc. Most isolates solubilized TCP and RP along with the lowering of media pH, indicating acidification to be the chief mechanism behind this solubilization. However, lowering of media pH and P release decreased by 32-100% when media was supplemented with succinate, a major component of plant root exudates indicating succinate mediated repression of P solubilization. Maximum TCP and RP solubilization with P release of 850μg/mL and 2088μg/mL was obtained with lowering of media pH up to 2.8 and 3.3 for isolate E43 and PSB1 respectively. This pH drop changed to 4.4 and 4.8 with 80% and 87% decrease in P solubilization in the presence of succinate. Maximum 246μg/mL indole 3-acetic acid production in Lh3, 44.8U/mL chitinase activity in MB3, 11.3U/mL phytase activity in I91 and 9.4U/mL alkaline phosphatase activity in SM1 were also obtained. Most isolates showed multiple PGP traits which resulted in significant plant growth promotion of chick pea plants. Present study shows repression of P solubilization by succinate for various bacterial groups which might be one of the reasons why phosphate solubilizing bacteria which perform well in vitro often fail in vivo. Studying this repression mechanism might be critical in understanding the in vivo efficacy. Copyright © 2017. Published by Elsevier GmbH.

  2. De novo quence analysis and intact mass measurements for characterization of phycocyanin subunit isoforms from the blue-green alga Aphanizomenon flos-aquae

    DEFF Research Database (Denmark)

    Rinalducci, Sara; Roepstorff, Peter; Zolla, Lello

    2009-01-01

    In this work, partial characterization of the primary structure of phycocyanin from the cyanobacterium Aphanizomenon flos-aquae (AFA) was achieved by mass spectrometry de novo sequencing with the aid of chemical derivatization. Combining N-terminal sulfonation of tryptic peptides by 4-sulfophenyl...

  3. De novo sequence analysis and intact mass measurements for characterization of phycocyanin subunit isoforms from the blue-green alga Aphanizomenon flos-aquae.

    Science.gov (United States)

    Rinalducci, Sara; Roepstorff, Peter; Zolla, Lello

    2009-04-01

    In this work, partial characterization of the primary structure of phycocyanin from the cyanobacterium Aphanizomenon flos-aquae (AFA) was achieved by mass spectrometry de novo sequencing with the aid of chemical derivatization. Combining N-terminal sulfonation of tryptic peptides by 4-sulfophenyl isothiocyanate (SPITC) and MALDI-TOF/TOF analyses, facilitated the acquisition of sequence information for AFA phycocyanin subunits. In fact, SPITC-derivatized peptides underwent facile fragmentation, predominantly resulting in y-series ions in the MS/MS spectra and often exhibiting uninterrupted sequences of 20 or more amino acid residues. This strategy allowed us to carry out peptide fragment fingerprinting and de novo sequencing of several peptides belonging to both alpha- and beta-phycocyanin polypeptides, obtaining a sequence coverage of 67% and 75%, respectively. The presence of different isoforms of phycocyanin subunits was also revealed; subsequently Intact Mass Measurements (IMMs) by both MALDI- and ESI-MS supported the detection of these protein isoforms. Finally, we discuss the evolutionary importance of phycocyanin isoforms in cyanobacteria, suggesting the possible use of the phycocyanin operon for a correct taxonomic identity of this species. Copyright (c) 2009 John Wiley & Sons, Ltd.

  4. Effect of light on the content of photosynthetically active pigments in plants. Pt. 4. Chromatic adaption in blue-green algae Anabaena cylindrica and A. variabilis

    Energy Technology Data Exchange (ETDEWEB)

    Czeczuga, B.

    1986-07-15

    The photosynthetic pigments (chlorophyll a, carotenoids and phycobiliprotein pigments) of two species of the genus Anabaena grown in white, red, yellow, green and blue light were examined. The highest concentration of the cells was observed in the sample with red light in case of the both species, and the smallest with blue light. The biggest amounts of chlorophyll a and carotenoids were included in the cells of samples with the yellow and the smallest in case of the red light. The ratio of two phycobiliproteins is as follows: - in Anabaena cylindrica: the highest amount of C-phycocyanin in the cells was observed in the case of the red light, and C-phycoerytherin was found in the blue light; - in Anabaena variabiles: the highest amount of C-phycocyanien in the cells was found in case of the yellow light, and allophycocyanin was found in the blue light.

  5. 蓝、绿藻SOD同工酶类型及其进化%Evolution of Blue-Green Algae through Analyzing Their Superoxide Dismutase Isozyme Types

    Institute of Scientific and Technical Information of China (English)

    陶明煊; 吴国荣; 魏锦城

    1999-01-01

    以新鲜蓝藻极大螺旋藻(Spirulina maxima)、钝顶螺旋藻(Spirulina platensis)、盐泽螺旋藻(Spirulina subsalsa)、单细胞绿藻盐藻(Dunaliella salina) 、多细胞绿藻轮藻(Chara)、水绵(Spirogyra)和鞘藻(Odeogonium)为实验材料.经抽滤、超声波破碎后,进行聚丙烯酰胺凝胶梯度电泳和抑制剂处理,结果表明三种螺旋藻都只含有Fe-SOD,其中极大螺旋藻、钝顶螺旋藻含有4条Fe-SOD同工酶谱带,而盐泽螺旋藻含有6条谱带;盐藻、水绵、鞘藻含有Fe-SOD和Mn-SOD两种类型,而轮藻含有Fe-SOD、Mn-SOD和Cu.Zn-SOD三种类型.

  6. Comparative effect of lunar fines and terrestrtrial ash on the growth of a blue-green alga and germinating radish seeds

    Science.gov (United States)

    Ridley, E. J.

    1983-01-01

    Although it is understood that photosynthetic organisms will be required as components of a closed ecological life support system (CELSS) for a manned lunar based, a basic problem is to identify organisms best capable of utilizing lunar regolith materials. Also, there is need to determine what nutrient supplements have to be added to lunar soils, and at what levels in order to promote high bio-mass production.

  7. Origin and evolution of osmoregulatory mechanisms in blue-green algae (cyanobacteria) as a function of metabolic and structural complexity: Reflections of Precambrian paleobiology

    Science.gov (United States)

    Yopp, John H.; Tindall, Donald R.; Pavlicek, Kenneth

    1987-01-01

    Major accomplishments underlying the basic understanding of cyanobacterial resistance to salt tolerance and osmotic stress were made. The methodology proposed included: the tracing of the pathways of formation of osmoregulatory solutes by traditional methods involving C-14 labelled substrates; gas chromatography; amino acid analysis; X-ray analysis using scanning transmission electron microscopy; and most importantly, C-13 labelled substrates, followed by Nuclear Magnetic Resonance (NMR) spectroscopy. It was found that the cyanobacteria employ a diversity of organic, osmoregulatory solutes. Osmoregulatory solutes were found to serve four functions: adjustment of water activity, noninhibition of enzymes; lowering of K sub m of enzymes to allow functioning at normal levels when the intracellular salt accumulates, and extending the pH optimum of enzymes as intracellular pH rises due to proton-potassium ion pump action during osmoregulation. Differences in osmoregulatory solutes may, but are not always, be attributed to differences in nutritional capabilities. The mechanism of osmoregulation and concomitant salt tolerance in halophilic cyanobacteria was elucidated. The activities of betaine and S-Adenosylhomocysteine hydrolase are discussed.

  8. Study on manufacture of nutritional blue-green algae oral liquid%蓝绿藻营养口服液的研制

    Institute of Scientific and Technical Information of China (English)

    付桂明; 万茵; 吕颖峰; 李文国; 万国明

    2008-01-01

    据研究,小球藻中含丰富的小球藻蛋白和绿藻生长因子(C.G.F),有促进生长的作用,螺旋藻的成分藻蓝蛋白有抗癌和增强免疫力作用.本研究利用小球藻(Chlorella)和螺旋藻(Spirulina)为原料研制蓝绿藻营养口服液.以藻粉为原料,将其复水后采用高压均质对小球藻和螺旋藻破壁;并采用木瓜蛋白酶酶解,以提高小球藻有效成分的抽提率;用等电沉淀法制取藻蓝蛋白,并加入绿藻提取液中.通过比较添加葡萄糖矫味、β-环状糊精包埋、活性炭吸附、酵母发酵四种脱腥方法,结果表明添加β-环糊精是最佳的蓝绿藻提取液脱腥方法.选用正交实验优化的调配方案,结果显示,在蓝绿藻提取液(绿藻多肽含量约2%,藻蓝蛋白含量约0.2%)中加入2%β-环糊精、0.04%柠檬酸和5%蔗糖,可制得无藻腥味、呈半透明、淡紫色的蓝绿藻营养口服液.

  9. Stabilization of Human Serum Albumin by the Binding of Phycocyanobilin, a Bioactive Chromophore of Blue-Green Alga Spirulina: Molecular Dynamics and Experimental Study.

    Science.gov (United States)

    Radibratovic, Milica; Minic, Simeon; Stanic-Vucinic, Dragana; Nikolic, Milan; Milcic, Milos; Cirkovic Velickovic, Tanja

    2016-01-01

    Phycocyanobilin (PCB) binds with high affinity (2.2 x 106 M-1 at 25°C) to human serum albumin (HSA) at sites located in IB and IIA subdomains. The aim of this study was to examine effects of PCB binding on protein conformation and stability. Using 300 ns molecular dynamics (MD) simulations, UV-VIS spectrophotometry, CD, FT-IR, spectrofluorimetry, thermal denaturation and susceptibility to trypsin digestion, we studied the effects of PCB binding on the stability and rigidity of HSA, as well as the conformational changes in PCB itself upon binding to the protein. MD simulation results demonstrated that HSA with PCB bound at any of the two sites showed greater rigidity and lower overall and individual domain flexibility compared to free HSA. Experimental data demonstrated an increase in the α-helical content of the protein and thermal and proteolytic stability upon ligand binding. PCB bound to HSA undergoes a conformational change to a more elongated conformation in the binding pockets of HSA. PCB binding to HSA stabilizes the structure of this flexible transport protein, making it more thermostable and resistant to proteolysis. The results from this work explain at molecular level, conformational changes and stabilization of HSA structure upon ligand binding. The resultant increased thermal and proteolytic stability of HSA may provide greater longevity to HSA in plasma.

  10. Determination of Vacuoles from the Blue-green Algae by Squash Method%压片法检查蓝藻液泡

    Institute of Scientific and Technical Information of China (English)

    郭厚良; 赵以军; 吴红艳

    2001-01-01

    鱼腥藻7120(Anabaena sp.PCC 7120)在含0.1 mol/L NaCl的条件下培养4 d,90%以上细胞液泡化.若在正常条件下培养,1个多月之后部分细胞开始液泡化,随着培养时间延长,液泡化细胞比例逐渐提高.液泡化藻丝材料在玻片上经手指轻轻施压,细胞破裂,液泡从细胞破裂处释出.所释放液泡完全透明,大小不等,可在相差显微镜下显示,个别液泡可弹至细胞外远处.无机盐诱导的液泡化和细胞衰老引起的液泡化之间具有明显的平行性.

  11. Sensitivity of green and blue-green algae to methyl tert-butyl ether (MTBE) during a fifteen-day test

    Institute of Scientific and Technical Information of China (English)

    CHEN Jianmeng; MA Jianyi; CAO Wei; WANG Pinwei; TONG Senmiao; SUN Yizhao

    2009-01-01

    The test was designed to assess the toxicity of methyl tert-butyl ether (MTBE) to Chlorella ellipsoidea and Aphanizomenon flos-aquae during 15 d with concentrations of MTBE from high (2.00×104 mg/L) to low (2 mg/L). The results showed that the toxicity was low when the concentration of MTBE was 1.00×104-2.00×104 mg/L (the greatest inhibition of growth-rate was 70%-71%, occurring on day 1-5). Low concentrations (2-500 mg/L) stimulated algal growth up to the greatest effect of 85%-200% when the concentration of MTBE was 50-100 mg/L on day 3-5. The low concentrations may lead to an algal bloom owing to overabundance, which represents an aquatic ecological risk. However, the stimulatory effect occurred only during the day 1-5 and disappeared gradually during the day 13-15. The toxicity of MTBE (72-120 h EC50) is 6.65×103-9.58×103 mg/L for C. ellipsoidea and that is 1.14×104-2.00×104 mg/L for A. spiroides. We found that the toxicity and ecological risk of MTBE for the algal community structure were low. The toxicity was influenced by the duration of the test. We suggest that the duration of the test should not be shorter than half a life-cycle.

  12. Design and application of an oligonucleotide microarray (nifH-phylochip) for nifH gene-based detection of nitrogen-fixing prokaryotes

    OpenAIRE

    Zhang, Lei

    2005-01-01

    Biological nitrogen fixation, the enzymatic reduction of N:sub:2:/sub: to ammonium, is anexclusively prokaryotic process which is crucial to balance the global nitrogen cycle.The key enzyme of this process -- nitrogenase -- has been highly conserved throughevolution. Transcription of one of the nitrogenase structural genes, nifH, provides apractical genetic marker for nitrogen fixing conditions and diazotrophic activities, as itis not constitutively expressed and is regulated in response to f...

  13. Diversity of free-living nitrogen-fixing microorganisms in wastelands of copper mine tailings during the process of natural ecological restoration.

    Science.gov (United States)

    Zhan, Jing; Sun, Qingye

    2011-01-01

    Biological nitrogen fixing is an important source of nitrogen input in the natural ecological restoration of mine wastelands. The diversity of nifH genes in tailings samples under different plant communities in Yangshanchong and Tongguanshan wastelands in Tongling, was analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach. The nitrogen-fixing microorganism community in the upper layer of tailings of Tongguanshan wasteland discarded in 1980 showed higher Shannon-Wiener diversity index than that in Yangshanchong wasteland discarded in 1991. The diversity of nifH genes in Yangshanchong wasteland of copper mine tailings did not display a consistent successional tendency with development of plant communities during the process of natural ecological restoration. Phylogenetic analysis of 25 sequences of nifH gene fragments retrieved from the DGGE gels indicated that there were mainly two taxa of free-living nitrogen-fixing microorganisms, Proteobacteria and Cyanobacteria living in the wastelands investigated, most of which were unique and uncultured. Canonical correspondence analysis (CCA) based on the relationship between band patterns of DGGE profile and physico-chemical properties of tailings samples showed that the diversity of nifH genes in different tailing samples was mainly affected by loss of ignition, water content, pH and available Zn contents of wastelands. The dominant plant species and development period of plant communities by ameliorating pH, reducing the toxicity of heavy metals, increasing organic matter and water content affected the diversity and structure of the free-living nitrogen-fixing microorganisms in wastelands of copper mine tailings.

  14. Simulating changes in ecosystem structure and composition in response to climate change: a case study focused on tropical nitrogen-fixing trees (Invited)

    Science.gov (United States)

    Medvigy, D.; Levy, J.; Xu, X.; Batterman, S. A.; Hedin, L.

    2013-12-01

    Ecosystems, by definition, involve a community of organisms. These communities generally exhibit heterogeneity in their structure and composition as a result of local variations in climate, soil, topography, disturbance history, and other factors. Climate-driven shifts in ecosystems will likely include an internal re-organization of community structure and composition and as well as the introduction of novel species. In terms of vegetation, this ecosystem heterogeneity can occur at relatively small scales, sometimes of the order of tens of meters or even less. Because this heterogeneous landscape generally has a variable and nonlinear response to environmental perturbations, it is necessary to carefully aggregate the local competitive dynamics between individual plants to the large scales of tens or hundreds of kilometers represented in climate models. Accomplishing this aggregation in a computationally efficient way has proven to be an extremely challenging task. To meet this challenge, the Ecosystem Demography 2 (ED2) model statistically characterizes a distribution of local resource environments, and then simulates the competition between individuals of different sizes and species (or functional groupings). Within this framework, it is possible to explicitly simulate the impacts of climate change on ecosystem structure and composition, including both internal re-organization and the introduction of novel species or functional groups. This presentation will include several illustrative applications of the evolution of ecosystem structure and composition under climate change. One application pertains to the role of nitrogen-fixing species in tropical forests. Will increasing CO2 concentrations increase the demand for nutrients and perhaps give a competitive edge to nitrogen-fixing species? Will potentially warmer and drier conditions make some tropical forests more water-limited, reducing the demand for nitrogen, thereby giving a competitive advantage to non-nitrogen-fixing

  15. Diversity and Activity of Free-Living Nitrogen-Fixing Bacteria and Total Bacteria in Organic and Conventionally Managed Soils ▿ †

    OpenAIRE

    Orr, Caroline H.; James, Angela; Leifert, Carlo; Cooper, Julia M.; Cummings, Stephen P.

    2010-01-01

    Agricultural soils are heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, the molecular ecology of the total bacterial and free-living nitrogen-fixing communities in soils from the Nafferton Factorial Systems Comparison (NFSC) study in northeast England were examined. The field experiment was factorial in design, with organic versus conventional crop rotation, crop protection, and fertility management fact...

  16. Monolithic integration of InGaN segments emitting in the blue, green, and red spectral range in single ordered nanocolumns

    Energy Technology Data Exchange (ETDEWEB)

    Albert, S.; Bengoechea-Encabo, A.; Sanchez-Garcia, M. A.; Calleja, E. [ISOM and Dept. Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Kong, X.; Trampert, A. [Paul-Drude-Institut fuer Festkoeperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2013-05-06

    This work reports on the selective area growth by plasma-assisted molecular beam epitaxy and characterization of InGaN/GaN nanocolumnar heterostructures. The optimization of the In/Ga and total III/V ratios, as well as the growth temperature, provides control on the emission wavelength, either in the blue, green, or red spectral range. An adequate structure tailoring and monolithic integration in a single nanocolumnar heterostructure of three InGaN portions emitting in the red-green-blue colors lead to white light emission.

  17. Monolithic integration of InGaN segments emitting in the blue, green, and red spectral range in single ordered nanocolumns

    Science.gov (United States)

    Albert, S.; Bengoechea-Encabo, A.; Kong, X.; Sanchez-Garcia, M. A.; Calleja, E.; Trampert, A.

    2013-05-01

    This work reports on the selective area growth by plasma-assisted molecular beam epitaxy and characterization of InGaN/GaN nanocolumnar heterostructures. The optimization of the In/Ga and total III/V ratios, as well as the growth temperature, provides control on the emission wavelength, either in the blue, green, or red spectral range. An adequate structure tailoring and monolithic integration in a single nanocolumnar heterostructure of three InGaN portions emitting in the red-green-blue colors lead to white light emission.

  18. Closed and continuous algae cultivation system for food production and gas exchange in CELSS

    Science.gov (United States)

    Oguchi, Mitsuo; Otsubo, Koji; Nitta, Keiji; Shimada, Atsuhiro; Fujii, Shigeo; Koyano, Takashi; Miki, Keizaburo

    In CELSS (Controlled Ecological Life Support System), utilization of photosynthetic algae is an effective means for obtaining food and oxygen at the same time. We have chosen Spirulina, a blue-green alga, and have studied possibilities of algae utilization. We have developed an advanced algae cultivation system, which is able to produce algae continuously in a closed condition. Major features of the new system are as follows. o (1)In order to maintain homogeneous culture conditions, the cultivator was designed so as to cause a swirl on medium circulation. (2)Oxygen gas separation and carbon dioxide supply are conducted by a newly designed membrane module. (3)Algae mass and medium are separated by a specially designed harvester. (4)Cultivation conditions, such as pH, temperature, algae growth rate, light intensity and quanlity of generated oxygen gas are controlled by a computer system and the data are automatically recorded. This equipment is a primary model for ground experiments in order to obtain some design data for space use. A feasibility of algae cultivation in a closed condition is discussed on the basis of data obtained by use of this new system.

  19. A Photo-Labile Thioether Linkage to Phycoviolobilin Provides the Foundation for the Blue/Green Photocycles in DXCF-Cyanobacteriochromes

    Energy Technology Data Exchange (ETDEWEB)

    Burgie, E. Sethe [Univ. of Wisconsin, Madison, WI (United States); Walker, Joseph M. [Univ. of Wisconsin, Madison, WI (United States); Phillips Jr., George N. [Univ. of Wisconsin, Madison, WI (United States); Rice Univ., Houston, TX (United States); Vierstra, Richard D. [Univ. of Wisconsin, Madison, WI (United States)

    2013-01-08

    The phytochrome superfamily encompasses a diverse collection of photochromic photoreceptors in plants and microorganisms that employ a covalently linked bilin cradled in a cGMP-phosphodiesterase/adenylyl-cyclase/FhlA (GAF) domain to detect light. Whereas most interconvert between red- and far-red-light-absorbing states, cyanobacteria also express variants called cyanobacteriochromes (CBCRs) that modify bilin absorption to collectively perceive the entire visible spectrum. Here, we present two X-ray crystallographic structures of the GAF domain from the blue/green photochromic CBCR PixJ from Thermosynechococcus elongatus. Moreover, these structures confirm the hypothesis that CBCRs variably manipulate the chromophore π-conjugation system through isomerization and a second thioether linkage, in this case involving the bilin C10 carbon and Cys494 within a DXCF sequence characteristic of blue/green CBCRs. Biochemical studies support a mechanism for photoconversion whereby the second linkage ruptures on route to the green-light-absorbing state. All together, theTePixJ(GAF) models illustrate the remarkable structural and photochemical versatility among phytochromes and CBCRs in driving light perception.

  20. Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Quantitation of Microcystins in Blue-Green Algal Dietary Supplements.

    Science.gov (United States)

    Parker, Christine H; Stutts, Whitney L; DeGrasse, Stacey L

    2015-12-02

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous detection and quantitation of seven microcystin congeners (1-7) and nodularin-R (8) in blue-green algal dietary supplements. Single-laboratory method validation data were collected in four supplement matrices (capsule, liquid, powder, and tablet) fortified at toxin concentrations from 0.25-2.00 μg/g (ppm). Average recoveries and relative standard deviations (RSD) using matrix-corrected solvent calibration curves were 101% (6% RSD) for all congeners and supplements investigated. Limits of detection (0.006-0.028 μg/g) and quantitation (0.018-0.084 μg/g) were sufficient to confirm the presence of microcystin contamination at the Oregon-mandated guidance concentration of 1.0 μg of microcystin-LReq/g. Quantitated concentrations of microcystin contamination in market-available Aphanizomenon flos-aquae blue-green algal supplements ranged from 0.18-1.87 μg of microcystin-LReq/g for detected congeners microcystin-LR, microcystin-LA, and microcystin-LY (3-5). Microcystin-RR, -YR, -LW, and -LF and nodularin-R (1, 2, and 6-8) were not detected in the supplements examined.

  1. System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum.

    Directory of Open Access Journals (Sweden)

    Kristin Collier Valle

    Full Text Available Due to the selective attenuation of solar light and the absorption properties of seawater and seawater constituents, free-floating photosynthetic organisms have to cope with rapid and unpredictable changes in both intensity and spectral quality. We have studied the transcriptional, metabolic and photo-physiological responses to light of different spectral quality in the marine diatom Phaeodactylum tricornutum through time-series studies of cultures exposed to equal doses of photosynthetically usable radiation of blue, green and red light. The experiments showed that short-term differences in gene expression and profiles are mainly light quality-dependent. Transcription of photosynthesis-associated nuclear genes was activated mainly through a light quality-independent mechanism likely to rely on chloroplast-to-nucleus signaling. In contrast, genes encoding proteins important for photoprotection and PSII repair were highly dependent on a blue light receptor-mediated signal. Changes in energy transfer efficiency by light-harvesting pigments were spectrally dependent; furthermore, a declining trend in photosynthetic efficiency was observed in red light. The combined results suggest that diatoms possess a light quality-dependent ability to activate photoprotection and efficient repair of photodamaged PSII. In spite of approximately equal numbers of PSII-absorbed quanta in blue, green and red light, the spectral quality of light is important for diatom responses to ambient light conditions.

  2. Thickness and annealing effects on thermally evaporated InZnO thin films for gas sensors and blue, green and yellow emissive optical devices

    Science.gov (United States)

    Sugumaran, Sathish; Jamlos, Mohd Faizal; Ahmad, Mohd Noor; Bellan, Chandar Shekar; Sivaraj, Manoj

    2016-08-01

    Indium zinc oxide (InZnO) thin films with thicknesses of 100 nm and 200 nm were deposited on glass plate by thermal evaporation technique. Fourier transform infrared spectra showed a strong metal-oxide bond. X-ray diffraction patterns revealed amorphous nature for as-deposited film whereas polycrystalline structure for annealed films. Scanning electron microscope images showed a uniform distribution of spherical shape grains. Grain size was found to be higher for 200 nm film than 100 nm film. The presence of elements (In, Zn and O) was confirmed from energy dispersive X-ray analysis. Photoluminescence study of 200 nm film showed a blue, blue-green and blue-yellow emission whereas 100 nm film showed a broad green and green-yellow emissions. Both 100 nm and 200 nm films showed good oxygen sensitivity from room temperature to 400 °C. The observed optical and sensor results indicated that the prepared InZnO films are highly potential for room temperature gas sensor and blue, green and yellow emissive opto-electronic devices.

  3. System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum.

    Science.gov (United States)

    Valle, Kristin Collier; Nymark, Marianne; Aamot, Inga; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Brembu, Tore; Bones, Atle M

    2014-01-01

    Due to the selective attenuation of solar light and the absorption properties of seawater and seawater constituents, free-floating photosynthetic organisms have to cope with rapid and unpredictable changes in both intensity and spectral quality. We have studied the transcriptional, metabolic and photo-physiological responses to light of different spectral quality in the marine diatom Phaeodactylum tricornutum through time-series studies of cultures exposed to equal doses of photosynthetically usable radiation of blue, green and red light. The experiments showed that short-term differences in gene expression and profiles are mainly light quality-dependent. Transcription of photosynthesis-associated nuclear genes was activated mainly through a light quality-independent mechanism likely to rely on chloroplast-to-nucleus signaling. In contrast, genes encoding proteins important for photoprotection and PSII repair were highly dependent on a blue light receptor-mediated signal. Changes in energy transfer efficiency by light-harvesting pigments were spectrally dependent; furthermore, a declining trend in photosynthetic efficiency was observed in red light. The combined results suggest that diatoms possess a light quality-dependent ability to activate photoprotection and efficient repair of photodamaged PSII. In spite of approximately equal numbers of PSII-absorbed quanta in blue, green and red light, the spectral quality of light is important for diatom responses to ambient light conditions.

  4. Azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects.

    Science.gov (United States)

    Steenhoudt, O; Vanderleyden, J

    2000-10-01

    Azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. Other free-living diazotrophs repeatedly detected in association with plant roots, include Acetobacter diazotrophicus, Herbaspirillum seropedicae, Azoarcus spp. and Azotobacter. Four aspects of the Azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones. Each of these aspects is dealt with in a comparative way. Azospirilla are predominantly surface-colonizing bacteria, whereas A. diazotrophicus, H. seropedicae and Azoarcus sp. are endophytic diazotrophs. The attachment of Azospirillum cells to plant roots occurs in two steps. The polar flagellum, of which the flagellin was shown to be a glycoprotein, mediates the adsorption step. An as yet unidentified surface polysaccharide is believed to be essential in the subsequent anchoring phase. In Azoarcus sp. the attachment process is mediated by type IV pili. Nitrogen fixation structural genes (nif) are highly conserved among all nitrogen-fixing bacteria, and in all diazotrophic species of the class of proteobacteria examined, the transcriptional activator NifA is required for expression of other nif genes in response to two major environmental signals (oxygen and fixed N). However, the mechanisms involved in this control can vary in different organisms. In Azospirillum brasilense and H. seropedicae (alpha- and beta-subgroup, respectively), NifA is inactive in conditions of excess nitrogen. Activation of NifA upon removal of fixed N seems to involve, either directly or indirectly, the signal transduction protein P(II). The presence of four conserved cysteine residues in the NifA protein might be an indication that NifA is directly sensitive to oxygen. In Azotobacter vinelandii (gamma-subgroup) nifA is cotranscribed with a second gene nifL. The nifL gene product inactivates NifA in response to high oxygen tension and cellular

  5. Meteorological effects on variation of airborne algae in Mexico

    Science.gov (United States)

    Rosas, Irma; Roy-Ocotla, Guadalupe; Mosiño, Pedro

    1989-09-01

    Sixteen species of algae were collected from 73.8 m3 of air. Eleven were obtained in Minatitlán and eleven in México City. The data show that similar diversity occurred between the two localities, in spite of the difference in altitude. This suggests that cosmopolitan airborne microorganisms might have been released from different sources. Three major algal divisions (Chlorophyta, Cyanophyta and Chrysophyta) formed the airborne algal group. Also, a large concentration of 2220 algae m-3 was found near sea-level, while lower amounts were recorded at the high altitude of México City. The genera Scenedesmus, Chlorella and Chlorococcum dominated. Striking relationships were noted between the concentration of airborne green and blue-green algae, and meteorological conditions such as rain, vapour pressure, temperature and winds for different altitudes. In Minatitlán a linear relationship was established between concentration of algae and both vapour pressure (mbar) and temperature (° C), while in México City the wind (m s-1) was associated with variations in the algal count.

  6. Membrane targeting of MnSOD is essential for oxidative stress tolerance of nitrogen-fixing cultures of Anabaena sp. strain PCC7120.

    Science.gov (United States)

    Raghavan, Prashanth S; Rajaram, Hema; Apte, Shree Kumar

    2015-07-01

    The nitrogen-fixing cyanobacterium, Anabaena PCC7120 encodes for a membrane-targeted 30 kDa Mn-superoxide dismutase (MnSOD) and a cytosolic FeSOD. The MnSOD is post-translationally processed to 27 and 24 kDa forms in the cytosol and periplasm/thylakoid lumen. The extent of cleavage of signal and linker peptides at the N-terminus is dependent on the availability of combined nitrogen during growth. While the 24 and 27 kDa forms are present in near equal proportions under nitrogen-fixing conditions, the 24 kDa form is predominant under nitrogen-supplemented conditions. Individual contribution of these forms of MnSOD to total oxidative stress tolerance was analysed using recombinant Anabaena strains overexpressing either different molecular forms of MnSOD or MnSOD defective in the cleavage of signal/linker peptide. Targeting of MnSOD to the membrane and subsequent cleavage to release both the 24 and 27 kDa forms was essential for oxidative stress tolerance under nitrogen-fixing conditions. On the other hand, the cleavage of linker peptide was absolutely essential and the release of cytosolic 24 kDa form of MnSOD was obligatory for developing oxidative stress tolerance under nitrogen-supplemented conditions. Thus, a single MnSOD caters to the reduction of superoxide radical in both cytosol and thylakoid lumen/periplasm irrespective of the N-status of growth by regulating its cleavage. This is the first report on the physiological advantage of membrane-targeting and processing of MnSOD in either bacteria or plants. The higher oxidative stress tolerance offered by the cytosolic form of MnSOD has possibly resulted in retention of only the cytosolic form in bacterial non-nitrogen-fixers during evolution.

  7. Diversity of free-living nitrogen-fixing microorganisms in wastelands of copper mine tailings during the process of natural ecological restoration

    Institute of Scientific and Technical Information of China (English)

    Jing Zhan; Qingye Sun

    2011-01-01

    Biological nitrogen fixing is an important source of nitrogen input in the natural ecological restoration of mine wastelands.The diversity of nifH genes in tailings samples under different plant communities in Yangshanchong and Tongguanshan wastelands in Tongling, was analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) approach.The nitrogen-fixing microorganism community in the upper layer of tailings of Tongguanshan wasteland discarded in 1980 showed higher Shannon-Wiener diversity index than that in Yangshanchong wasteland discarded in 1991.The diversity of nifH genes in Yangshanchong wasteland of copper mine tailings did not display a consistent successional tendency with development of plant communities during the process of natural ecological restoration.Phylogenetic analysis of 25 sequences of nifH gene fragments retrieved from the DGGE gels indicated that there were mainly two taxa of free-living nitrogen-fixing microorganisms, Proteobacteria and Cyanobacteria living in the wastelands investigated, most of which were unique and uncultured.Canonical correspondence analysis (CCA) based on the relationship between band patterns of DGGE profile and physico-chemical properties of tailings samples showed that the diversity of nifH genes in different tailing samples was mainly affected by loss of ignition, water content, pH and available Zn contents of wastelands.The dominant plant species and development period of plant communities by ameliorating pH, reducing the toxicity of heavy metals, increasing organic matter and water content affected the diversity and structure of the free-living nitrogenfixing microorganisms in wastelands of copper mine tailings.

  8. [Regulatory genes of garden pea (Pisum sativum L.) controlling the development of nitrogen-fixing nodules and arbuscular mycorrhiza: a review of basic and applied aspects

    DEFF Research Database (Denmark)

    Borisov, A Iu; Vasil'chikov, A G; Voroshilova, V A

    2007-01-01

    The review sums up the long experience of the authors and other researchers in studying the genetic system of garden pea (Pisum sativum L.), which controls sthe development of nitrogen-fixing symbiosis and arbuscular mycorrhiza. A justified phenotypic classification of pea mutants is presented....... Progress in identifying and cloning symbiotic genes is adequately reflected. The feasibility of using double inoculation as a means of increasing the plant productivity is demonstrated, in which the potential of a tripartite symbiotic system (pea plants-root nodule bacteria-arbuscular mycorrhiza...

  9. Expression of the 1-Aminocyclopropane-1-Carboxylic Acid Deaminase Gene Requires Symbiotic Nitrogen-Fixing Regulator Gene nifA2 in Mesorhizobium loti MAFF303099

    OpenAIRE

    Nukui, Noriyuki; MINAMISAWA, KIWAMU; Ayabe, Shin-Ichi; Aoki, Toshio

    2006-01-01

    Many soil bacteria contain 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, which degrades ACC, a precursor of the phytohormone ethylene. In order to examine the regulation of the acdS gene encoding ACC deaminase in Mesorhizobium loti MAFF303099 during symbiosis with the host legume Lotus japonicus, we introduced the β-glucuronidase (GUS) gene into acdS so that GUS was expressed under control of the acdS promoter, and we also generated disruption mutants with mutations in a nitrogen fix...

  10. High radiation and desiccation tolerance of nitrogen-fixing cultures of the cyanobacterium Anabaena sp. strain PCC 7120 emanates from genome/proteome repair capabilities.

    Science.gov (United States)

    Singh, Harinder; Anurag, Kirti; Apte, Shree Kumar

    2013-10-12

    The filamentous nitrogen-fixing cyanobacterium, Anabaena sp. strain PCC 7120 was found to tolerate very high doses of (60)Co-gamma radiation or prolonged desiccation. Post-stress, cells remained intact and revived all the vital functions. A remarkable capacity to repair highly disintegrated genome and recycle the damaged proteome appeared to underlie such high radioresistance and desiccation tolerance. The close similarity observed between the cellular response to irradiation or desiccation stress lends strong support to the notion that tolerance to these stresses may involve similar mechanisms.

  11. Burkholderia caballeronis sp. nov., a nitrogen fixing species isolated from tomato (Lycopersicon esculentum) with the ability to effectively nodulate Phaseolus vulgaris.

    Science.gov (United States)

    Martínez-Aguilar, Lourdes; Salazar-Salazar, Corelly; Méndez, Rafael Díaz; Caballero-Mellado, Jesús; Hirsch, Ann M; Vásquez-Murrieta, María Soledad; Estrada-de los Santos, Paulina

    2013-12-01

    During a survey of Burkholderia species with potential use in agrobiotechnology, a group of 12 strains was isolated from the rhizosphere and rhizoplane of tomato plants growing in Mexico (Nepantla, Mexico State). A phylogenetic analysis of 16S rRNA gene sequences showed that the strains are related to Burkholderia kururiensis and Burkholderia mimosarum (97.4 and 97.1 %, respectively). However, they induced effective nitrogen-fixing nodules on roots of Phaseolus vulgaris. Based on polyphasic taxonomy, the group of strains represents a novel species for which the name Burkholderia caballeronis sp. nov. is proposed. The type species is TNe-841(T) (= LMG 26416(T) = CIP 110324(T)).

  12. Algae Resources

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    Algae are highly efficient at producing biomass, and they can be found all over the planet. Many use sunlight and nutrients to create biomass, which contain key components—including lipids, proteins, and carbohydrates— that can be converted and upgraded to a variety of biofuels and products. A functional algal biofuels production system requires resources such as suitable land and climate, sustainable management of water resources, a supplemental carbon dioxide (CO2) supply, and other nutrients (e.g., nitrogen and phosphorus). Algae can be an attractive feedstock for many locations in the United States because their diversity allows for highpotential biomass yields in a variety of climates and environments. Depending on the strain, algae can grow by using fresh, saline, or brackish water from surface water sources, groundwater, or seawater. Additionally, they can grow in water from second-use sources such as treated industrial wastewater; municipal, agricultural, or aquaculture wastewater; or produced water generated from oil and gas drilling operations.

  13. Assessment of the effect of azo dye RP2B on the growth of a nitrogen fixing cyanobacterium--Anabaena sp.

    Science.gov (United States)

    Hu, T L; Wu, S C

    2001-03-01

    Certain nitrogen fixing cyanobacteria are diazotrophic, which profoundly impacts the aquatic ecosystem chemically and biologically. Although certain types are banned due to their carcinogenicity, azo dyes are commonly used in the dyeing or textile industry. This work investigates the effect of azo dye on the growth of cyanobacteria. Anabaena sp. isolated from the Da Jia Brook is an odor producing, nitrogen fixing cyanobacterium. The growth rates of Anabaena sp. in the media with or without nitrogen source were 3.56 x 10(-2) mg/ml day and 2.44 x 10(-2) mg/ml day, respectively. Anabaena sp. could not use azo dye RP2B as the nitrogen source. Experimental results indicated that the growth of Anabaena sp. was inhibited in the medium containing RP2B. The degree of inhibition increased from 50% to 81% with an increasing concentration of RP2B (0-50 mg/l). The IC-50 (inhibitory concentration) of RP2B on the growth of Anabaena sp. was 5 mg/l (as based on dry weight) or 7 mg/l (as measured by chlorophyll a).

  14. Alkaline shift effect on the uptake of germanium by algae, Chlorella ellipsoideae, Oscillatoria sp. and Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Yanagimoto, M. (National Food Research Inst., Ibaraki, Japan); Saitoh, H.; Kakimoto, N.

    1983-01-01

    The uptake of germanium (Ge) by microalgae was interesting because of a therapeutic effect of organic germanium. In the case of blue green algae, Oscillatoria sp. and Spirulina platensis, satisfactory amounts of Ge were accumulated in the cells, where the pH of the culture was shifted to 11.8 or 12.3, after sufficient growth. These algae could hardly grow in a culture at pH 11.8 or pH 12.3. In the case of Chlorella ellipsoideae, a good result could not be obtained. But a relatively high uptake of Ge into the cells could be obtained in the culture shifted to pH 8.6, in which the alga could hardly grow. Although the effective pHs are different, the effect of the elevated pH of the cultures can be called an alkaline shift effect from the same feature.

  15. Algae mediated synthesis of cadmium sulphide nanoparticles and their application in bioremediation

    Science.gov (United States)

    Prasad Mandal, Ranju; Sekh, Sanoyaz; Sarkar, Neera Sen; Chattopadhyay, Dipankar; De, Swati

    2016-05-01

    The present work is a study on the biological synthesis of cadmium sulphide (CdS) nanoparticles using blue-green algae that is popularly used as a food supplement. This synthesis is unique in the sense that no external sulphur precursor is required, the CdS nanoparticles are synthesized in situ in the algal medium. The CdS nanoparticles thus synthesized are photoluminescent and can act as highly efficient photocatalysts for degradation of the dye pollutant malachite green. Thus the CdS nanoparticles synthesized in situ in the algae conform to the desired criteria of waste water treatment i.e. biosorption of the pollutant and its subsequent degradation. The novelty of this work also lies in its potential for use in bioremediation by conversion of the toxic Cd(II) ion to less toxic CdS nanoparticles within the algal framework.

  16. Evaluation of the Effects of Bio Fertilizers Containing non Symbiotic Nitrogen Fixing and Phosphate Solubilizing Bacteria on Quantitative and Qualitative Traits of Wheat

    Directory of Open Access Journals (Sweden)

    M Mohtadi

    2016-02-01

    Full Text Available Introduction Wheat crop plays an important role in food security in a country such as Iran. Therefore, serious attention has been paid to ecological farming systems and sustainable management of wheat. For this purpose extensive efforts is done to find proper strategies to improve the quality of soil, agricultural products and started removal pollutants. One of the factors to achieve sustainable agriculture is to use natural agents such as biofertilizers. Several mechanisms are proposed to explain how effective plant growth promoting rhizobacteria is for growth and development of plants. These mechanisms include two groups, direct and indirect in general. Indirect mechanism is to increase absorption and availability of the nutrient elements soluble, producing plant growth regulators, siderophore production of iron chelator, and the phosphate soluble. Through indirect mechanisms such as antagonistic relation, PGPRs moderate the harmful effects of of plant pathogens and thereby lead to increase plant growth. The main goal of this study was to investigate the effect of biofertilizers containing non-symbiotic nitrogen fixing and phosphate solubilizing bacteria on quantitative and qualitative traits of wheat. Materials and Methods This Experiment was conducted in the research farm of Baykola agricultural research stations affiliated by agriculture and natural resources research center of Mazandaran during 2011-12 cropping season. In order to determine physical and chemical properties of the soil samples were taken from the depth of 0-30 cm,. Experimental design was split plots arrangement based on randomized complete block design with three replications. In this experiment chemical fertilizer was assumed as the main plot in 3 levels include: 1- noconsumption (C0, 2- equivalent to 50% of the fertilizer recommendations (C1, 3- equivalent to 100% of the fertilizer recommendations(C2 and two types of biological fertilizers was applied in the sub plot in

  17. Comparative effectiveness of ACC-deaminase and/or nitrogen-fixing rhizobacteria in promotion of maize (Zea mays L.) growth under lead pollution.

    Science.gov (United States)

    Hassan, Waseem; Bano, Rizwana; Bashir, Farhat; David, Julie

    2014-09-01

    Lead (Pb) pollution is appearing as an alarming threat nowadays. Excessive Pb concentrations in agricultural soils result in minimizing the soil fertility and health which affects the plant growth and leads to decrease in crop production. Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria which can protect the plants against many abiotic stresses, and enhance the growth. The study aimed to identify important rhizobacterial strains by using the 1-aminocyclopropane-1-carboxylate (ACC) enrichment technique and examine their inoculation effects in the growth promotion of maize, under Pb pollution. A pot experiment was conducted and six rhizobacterial isolates were used. Pb was added to 2 kg soil in each pot (with 4 seeds/pot) using Pb(NO3)2 at the rate of 0, 100, 200, 300, and 400 mg kg(-1) Pb with three replications in completely randomized design. Rhizobacterial isolates performed significantly better under all Pb levels, i.e., 100 to 400 Pb mg kg(-1) soil, compared to control. Comparing the efficacy of the rhizobacterial isolates under different Pb levels, rhizobacterial isolates having both ACC-deaminase and nitrogen-fixing activities (AN8 and AN12) showed highest increase in terms of the physical, chemical and enzymatic growth parameters of maize, followed by the rhizobacterial isolates having ACC-deaminase activity only (ACC5 and ACC8), and then the nitrogen-fixing rhizobia (Azotobacter and RN5). However, the AN8 isolate showed maximum efficiency, and highest shoot and root length (14.2 and 6.1 cm), seedling fresh and dry weights (1.91 and 0.14 g), chlorophyll a, b, and carotenoids (24.1, 30.2 and 77.7 μg/l), protein (0.82 mg/g), proline (3.42 μmol/g), glutathione S-transferase, peroxidase and catalase (12.3, 4.2 and 7.2 units/mg protein), while the lowest Pb uptake in the shoot and root (0.83 and 0.48 mg/kg) were observed under this rhizobial isolate at the highest Pb level (i.e., 400 Pb mg kg(-1) soil). The results revealed that PGPR

  18. Ascorbate oxidase: the unexpected involvement of a 'wasteful enzyme' in the symbioses with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Balestrini, Raffaella; Ott, Thomas; Güther, Mike; Bonfante, Paola; Udvardi, Michael K; De Tullio, Mario C

    2012-10-01

    Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO over-expressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that the expression of a Lotus japonicus AO gene is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi. In this framework, high AO expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of AM symbiosis. A general model of AO function in plants is discussed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  19. Complete Genome sequence of Burkholderia phymatum STM815T, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

    Science.gov (United States)

    Moulin, Lionel; Klonowska, Agnieszka; Caroline, Bournaud; Booth, Kristina; Vriezen, Jan A.C.; Melkonian, Rémy; James, Euan K.; Young, J. Peter W.; Bena, Gilles; Hauser, Loren; Land, Miriam; Kyrpides, Nikos; Bruce, David; Chain, Patrick; Copeland, Alex; Pitluck, Sam; Woyke, Tanja; Lizotte-Waniewski, Michelle; Bristow, Jim; Riley, Margaret

    2014-01-01

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp). PMID:25197461

  20. Complete Genome sequence of Burkholderia phymatum STM815, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, Lionel [UMR, France; Klonowska, Agnieszka [UMR, France; Caroline, Bournaud [UMR, France; Booth, Kristina [University of Massachusetts; Vriezen, Jan A.C. [University of Massachusetts; Melkonian, Remy [UMR, France; James, Euan [James Hutton Institute, Dundee, United Kingdom; Young, Peter W. [University of York, United Kingdom; Bena, Gilles [UMR, France; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Copeland, A [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lizotte-Waniewski, Michelle [University of Massachusetts; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Riley, Monica [Woods Hole Oceanographic Institution (WHOI), Woods Hole

    2014-01-01

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

  1. Complete Genome sequence of Burkholderia phymatum STM815(T), a broad host range and efficient nitrogen-fixing symbiont of Mimosa species.

    Science.gov (United States)

    Moulin, Lionel; Klonowska, Agnieszka; Caroline, Bournaud; Booth, Kristina; Vriezen, Jan A C; Melkonian, Rémy; James, Euan K; Young, J Peter W; Bena, Gilles; Hauser, Loren; Land, Miriam; Kyrpides, Nikos; Bruce, David; Chain, Patrick; Copeland, Alex; Pitluck, Sam; Woyke, Tanja; Lizotte-Waniewski, Michelle; Bristow, Jim; Riley, Margaret

    2014-06-15

    Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815(T), was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

  2. Biodegradation of the neonicotinoid insecticide thiamethoxam by the nitrogen-fixing and plant-growth-promoting rhizobacterium Ensifer adhaerens strain TMX-23.

    Science.gov (United States)

    Zhou, Guang-Can; Wang, Ying; Zhai, Shan; Ge, Feng; Liu, Zhong-Hua; Dai, Yi-Jun; Yuan, Sheng; Hou, Jun-Yi

    2013-05-01

    Thiamethoxam (THIA), a second generation neonicotinoid insecticide in the thianicotinyl subclass, is used worldwide. Environmental studies revealed that microbial degradation is the major mode of removal of this pesticide from soil. However, microbial transformation of THIA is poorly understood. In the present study, we isolated a bacterium able to degrade THIA from rhizosphere soil. The bacterium was identified as Ensifer adhaerens by its morphology and 16S ribosomal DNA sequence analysis. High-performance liquid chromatography and mass spectrometry analysis suggested that the major metabolic pathway of THIA in E. adhaerens TMX-23 involves the transformation of its N-nitroimino group (=N-NO2) to N-nitrosoimino (=N-NO) and urea (=O) metabolites. E. adhaerens TMX-23 is a nitrogen-fixing bacterium harboring two types of nifH genes in its genome, one of which is 98 % identical to the nifH gene in the cyanobacterium Calothrix sp. MCC-3A. E. adhaerens TMX-23 released various plant-growth-promoting substances including indole-3-acetic acid, exopolysaccharides, ammonia, HCN, and siderophores. Inoculation of E. adhaerens TMX-23 onto soybean seeds (Glycine max L.) with NaCl at 50, 100, or 154 mmol/L increased the seed germination rate by 14, 21, and 30 %, respectively. THIA at 10 mg/L had beneficial effects on E. adhaerens TMX-23, enhancing growth of the bacterium and its production of salicylic acid, an important plant phytohormone associated with plant defense responses against abiotic stress. The nitrogen-fixing and plant-growth-promoting rhizobacterium E. adhaerens TMX-23, which is able to degrade THIA, has the potential for bioaugmentation as well as to promote growth of field crops in THIA-contaminated soil.

  3. Symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers.

    Science.gov (United States)

    Cocking, Edward C; Stone, Philip J; Davey, Michael R

    2005-12-01

    It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium, Gluconacetobacter diazotrophicus that naturally occurs in sugarcane. G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization by G. diazotrophicus, with minimal or zero inputs.

  4. Symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers

    Institute of Scientific and Technical Information of China (English)

    Edward C. Cocking; Philip J. Stone; Michael R. Davey

    2005-01-01

    It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems,and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intraceliularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium, Gluconacetobacter diazotrophicus that naturally occurs in sugarcane. G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers,we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization by G. diazotrophicus,with minimal or zero inputs.

  5. An RNA-Seq Analysis of Grape Plantlets Grown in vitro Reveals Different Responses to Blue, Green, Red LED Light, and White Fluorescent Light.

    Science.gov (United States)

    Li, Chun-Xia; Xu, Zhi-Gang; Dong, Rui-Qi; Chang, Sheng-Xin; Wang, Lian-Zhen; Khalil-Ur-Rehman, Muhammad; Tao, Jian-Min

    2017-01-01

    Using an RNA sequencing (RNA-seq) approach, we analyzed the differentially expressed genes (DEGs) and physiological behaviors of "Manicure Finger" grape plantlets grown in vitro under white, blue, green, and red light. A total of 670, 1601, and 746 DEGs were identified in plants exposed to blue, green, and red light, respectively, compared to the control (white light). By comparing the gene expression patterns with the growth and physiological responses of the grape plantlets, we were able to link the responses of the plants to light of different spectral wavelengths and the expression of particular sets of genes. Exposure to red and green light primarily triggered responses associated with the shade-avoidance syndrome (SAS), such as enhanced elongation of stems, reduced investment in leaf growth, and decreased chlorophyll levels accompanied by the expression of genes encoding histone H3, auxin repressed protein, xyloglucan endotransglycosylase/hydrolase, the ELIP protein, and microtubule proteins. Furthermore, specific light treatments were associated with the expression of a large number of genes, including those involved in the glucan metabolic pathway and the starch and sucrose metabolic pathways; these genes were up/down-regulated in ways that may explain the increase in the starch, sucrose, and total sugar contents in the plants. Moreover, the enhanced root growth and up-regulation of the expression of defense genes accompanied with SAS after exposure to red and green light may be related to the addition of 30 g/L sucrose to the culture medium of plantlets grown in vitro. In contrast, blue light induced the up-regulation of genes related to microtubules, serine carboxypeptidase, chlorophyll synthesis, and sugar degradation and the down-regulation of auxin-repressed protein as well as a large number of resistance-related genes that may promote leaf growth, improve chlorophyll synthesis and chloroplast development, increase the ratio of chlorophyll a (chla

  6. Light harvesting and blue-green light induced non-photochemical quenching in two different C-phycocyanin mutants of Synechocystis PCC 6803.

    Science.gov (United States)

    Tian, Lijin; van Stokkum, Ivo H M; Koehorst, Rob B M; van Amerongen, Herbert

    2013-09-26

    Cyanobacteria are oxygen-evolving photosynthetic organisms that harvest sunlight and convert excitation energy into chemical energy. Most of the light is absorbed by large light harvesting complexes called phycobilisomes (PBs). In high-light conditions, cyanobacteria switch on a photoprotective mechanism called non-photochemical quenching (NPQ): During this process, absorption of blue-green light transforms the inactive orange form of the orange carotenoid protein OCP (OCP(o)) into the red active form OCP(r) that subsequently binds to the PB, resulting in a substantial loss of excitation energy and corresponding decrease of the fluorescence. In wild-type cells, the quenching site is a bilin chomophore that fluoresces at 660 nm and which is called APC(Q)(660). In the present work, we studied NPQ in two different types of mutant cells (CB and CK) that possess significantly truncated PBs, using spectrally resolved picosecond fluorescence spectroscopy. The results are in very good agreement with earlier in vitro experiments on quenched and unquenched PBs, although the fraction of quenched PBs is far lower in vivo. It is also lower than the fraction of PBs that is quenched in wild-type cells, but the site, rate, and location of quenching appear to be very similar.

  7. Blue-green BaAl2O4:Eu2+,Dy3+ phosphors synthesized via combustion synthesis method assisted by microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    SUN Feilong; ZHAO Junwu

    2011-01-01

    Blue-green luminescent BaAl2O4:Eu2+,Dy3+ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. The XRD results revealed that when the concentration of urea was over 3 times higher than theoretical quantities, a BaAl2O4 single hexagonal phase was obtained. The SEM results revealed that the surface of the BaAl2O4:Eu2+,Dy3+ powder samples showed lots of voids and pores. The BaAl2O4:Eu2+,Dy3+ phosphors exhibited a broad emission band of main peak at 496 nm and a shoulder peak at 426 nm under excitation of 337 nm. The BaAl2O4:Eu2+,Dy3+ phosphors at the Eu2+ concentration of 1 mol.% showed the strongest luminescent intensity. Long afterglow phosphorescence was observed in the dark with naked eyes after the removal of the excitation source.

  8. Sol-gel synthesized Sr4Al14O25:Eu2+/Dy3+ blue-green phosphorous as oxygen sensing materials

    Science.gov (United States)

    Aydin, Ilkyaz; Ertekin, Kadriye; Demirci, Selim; Gultekin, Serdar; Celik, Erdal

    2016-12-01

    In this study, we utilized newly synthesized Sr4Al14O25:Eu2+/Dy3+ blue-green phosphors along with silver nanoparticles (AgNPs) for fabrication of oxygen sensitive materials. To the best of our knowledge oxygen sensing mechanism of the offered design is totally different from the previously published works. One-component silicone: poly (1-trimethylsilyl-1-propyne), two component phenyl bearing silicone, plasticized polymethylmethacrylate, and ethylcellulose (EC) were tested as matrix materials. Electrospun fibers, porous and smooth thin films were produced by electrospinning or knife coating technique. Oxygen induced luminescence of the phosphors at 544 nm was followed as the analytical signal. Utilization of silver nanoparticles in silicone along with phosphors resulted with a 7.14 fold enhancement in the signal intensity and significant spectral response towards oxygen competing with the signals of the oxygen sensors utilizing metalloporphyrins or ruthenium complexes. We observed high sensitivity and stability, increased surface area and an enhancement in all sensor dynamics. Linearity of the calibration plots was superior for the pO2 range of 0.0-20.0% with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in signal intensity after 12 months. Our sensitivity and stability tests are still in progress.

  9. Blue-green tunable color of Ce3+/Tb3+ coactivated NaBa3La3Si6O20 phosphor via energy transfer

    Science.gov (United States)

    Jia, Zhen; Xia, Mingjun

    2016-01-01

    A series of color tunable phosphors NaBa3La3Si6O20:Ce3+, Tb3+ were synthesized via the high-temperature solid-state method. NaBa3La3Si6O20 crystallizes in noncentrosymmetric space group Ama2 with the cell parameters of a = 14.9226(4) Å, b = 24.5215(5) Å and c = 5.6241(2) Å by the Rietveld refinement method. The Ce3+ ions doped NaBa3La3Si6O20 phosphors have a strong absorption band from 260 to 360 nm and show near ultraviolet emission light centered at 378 nm. The Ce3+ and Tb3+ ions coactivated phosphors exhibit color tunable emission light from deep blue to green by adjusting the concentration of the Tb3+ ions. An energy transfer of Ce3+ → Tb3+ investigated by the photoluminescence properties and lifetime decay, is demonstrated to be dipole–quadrupole interaction. These results indicate the NaBa3La3Si6O20:Ce3+, Tb3+ phosphors can be considered as potential candidates for blue-green components for white light emitting diodes. PMID:27628111

  10. Diversity of free-living nitrogen-fixing microorganisms in the rhizosphere and non-rhizosphere of pioneer plants growing on wastelands of copper mine tailings.

    Science.gov (United States)

    Zhan, Jing; Sun, Qingye

    2012-03-20

    The composition of free-living nitrogen-fixing microbial communities in rhizosphere and non-rhizosphere of pioneer plants growing on wastelands of copper mine tailings was studied by the presence of nifH genes using Polymerase Chain Reaction-Denatured Gradient Gel Electrophoresis (PCR-DGGE) approach. Eleven rhizosphere tailing samples and nine non-rhizosphere tailing samples from six plant communities were collected from two wastelands with different discarded periods. The nested PCR method was used to amplify the nifH genes from environmental DNA extracted from tailing samples. Twenty-two of 37 nifH gene sequences retrieved from DGGE gels clustered in Proteobacteria (α-Proteobacteria and β-Proteobacteria) and 15 nifH gene sequences in Cyanobacteria. Most nifH gene fragments sequenced were closely related to uncultured bacteria and cyanobacteria and exhibited less than 90% nucleotide acid identity with bacteria in the database, suggesting that the nifH gene fragments detected in copper mine tailings may represent novel sequences of nitrogen-fixers. Our results indicated that the non-rhizosphere tailings generally presented higher diversity of nitrogen-fixers than rhizosphere tailings and the diversity of free-living nitrogen-fixers in tailing samples was mainly affected by the physico-chemical properties of the wastelands and plant species, especially the changes of nutrient and heavy metal contents caused by the colonization of plant community. Copyright © 2011 Elsevier GmbH. All rights reserved.

  11. Exopolysaccharide production by nitrogen-fixing bacteria within nodules of Medicago plants exposed to chronic radiation in the Chernobyl exclusion zone.

    Science.gov (United States)

    Pawlicki-Jullian, Nathalie; Courtois, Bernard; Pillon, Michelle; Lesur, David; Le Flèche-Mateos, Anne; Laberche, Jean-Claude; Goncharova, Nadia; Courtois, Josiane

    2010-03-01

    Nitrogen-fixing bacteria isolated from root nodules of Medicago plants growing in the 10 km zone around the Chernobyl nuclear power plant were screened for the production of new water-soluble acidic exopolysaccharides (EPSs). The different strains belonged to the Enteriobacteriaceae family (Enterobacter ludwigii, Raoultella terrigena, Klebsiella oxytoca), except for one which belonged to the Rhizobiaceae family (Sinorhizobium meliloti). All of the bacteria produced highly viscous EPS with an average molecular weight comprised between 1 x 10(6) and 3 x 10(6) Da. Five different compositions of EPS were characterized by physico-chemical analyses and (1)H NMR spectroscopy: galactose/mannose (2/1), galactose/glucose (1/1), galactose/glucose/mannose (1/2/1), fucose/galactose/glucose (2/1/1) and fucose/galactose/glucose/mannose (2/2/1/1 or 1/1/2/4). Glucuronic acid, a charged monosaccharide, was also recovered in most of the different EPSs. Copyright 2010 Elsevier Masson SAS. All rights reserved.

  12. Effect of free and symbiotic nitrogen fixing bacterial co-inoculation on seed and seedling of soybean seeds produced under deficit water condition

    Directory of Open Access Journals (Sweden)

    Hamed Hadi

    2016-04-01

    Full Text Available Effect of free and symbiotic nitrogen fixing bacteria on seed and seedling produced seeds under deficit irrigation was conducted in laboratory and field experiments in 2006. In laboratory of karaj’s Seed and Plant Research and Certificate Institute an experiment was conducted based on factorial in form of completely randomized design with four replications and in field’s of Islamic Azad University, Varamin Branch were split factorial in form of randomized completely block design with three replications. Treatments included water stress [Irrigation after 50 (Normal irrigation, 100 (Middle stress, 150 (Severe stress mm evaporation from pan class A], Cultivar [Manokin & Williams and SRF×T3 Line] and inoculation [Inoculation with Bradyrhizobium japonicum, Bradyrhizobium japonicum co-inoculated with Azotobacter chroococcum, No seed inoculation]. Results showed that drought stress decreased the uniformity and germination speed and seedling emergence. Bacteria increased leaf dry weight, stem dry weight, leaf area and seedling vigor index but had no effect on emergence. In irrigation levels inoculated treatments had higher seedling length, leaf, stem, seedling dry weight and seedling vigor. Severs stress seeds inoculated with Bradyrhizobium japonicum had higher root dry weight than control. Therefore in seeds which were produced under deficit irrigation conditions, bacteria increased seedlings vigor.

  13. Indole-3-acetic acid (IAA) production in symbiotic and non-symbiotic nitrogen-fixing bacteria and its optimization by Taguchi design.

    Science.gov (United States)

    Shokri, Dariush; Emtiazi, Giti

    2010-09-01

    Production of Indole-3-acetic acid (IAA) in 35 different symbiotic and non-symbiotic nitrogen-fixing bacteria strains isolated from soil and plant roots was studied and assayed by chromatography and colorimetric methods. These bacteria included Agrobacterium, Paenibacillus, Rhizobium, Klebsiella oxytoca, and Azotobacter. The best general medium and synergism effects of isolates for IAA production were investigated. Effects of different variables containing physical parameters and key media components and optimization of condition for IAA production were performed using the Design of Experiments. Qualitek-4 (W32b) software for automatic design and analysis of the experiments, both based on Taguchi method was used. The results showed that Rhizobium strains, symbiotic, and Paenibacillus non-symbiotic bacteria yielded the highest concentrations of IAA (in the range of 5.23-0.27 and 4.90-0.19 ppm IAA/mg biomass, respectively) and IAA production was increased by synergism effect of them. Yeast Extract Mannitol medium supplemented with L-tryptophan was the best general medium for IAA production. The analysis of experimental data using Taguchi method indicated that nitrogen source is very prominent variable in affecting the yield and mannitol as carbon source, potassium nitrate (1%), and L-tryptophan (3 g/l) as nitrogen sources after 72-h incubation at 30 degrees C were the optimum conditions for production of IAA. 5.89 ppm IAA/mg biomass was produced under these optimal conditions.

  14. Draft Genome Sequence of the Nitrogen-Fixing Rhizobium sullae Type Strain IS123T Focusing on the Key Genes for Symbiosis with its Host Hedysarum coronarium L.

    Directory of Open Access Journals (Sweden)

    Gaurav Sablok

    2017-07-01

    Full Text Available The prominent feature of rhizobia is their molecular dialogue with plant hosts. Such interaction is enabled by the presence of a series of symbiotic genes encoding for the synthesis and export of signals triggering organogenetic and physiological responses in the plant. The genome of the Rhizobium sullae type strain IS123T nodulating the legume Hedysarum coronarium, was sequenced and resulted in 317 scaffolds for a total assembled size of 7,889,576 bp. Its features were compared with those of genomes from rhizobia representing an increasing gradient of taxonomical distance, from a conspecific isolate (Rhizobium sullae WSM1592, to two congeneric cases (Rhizobium leguminosarum bv. viciae and Rhizobium etli and up to different genera within the legume-nodulating taxa. The host plant is of agricultural importance, but, unlike the majority of other domesticated plant species, it is able to survive quite well in the wild. Data showed that that the type strain of R. sullae, isolated from a wild host specimen, is endowed with a richer array of symbiotic genes in comparison to other strains, species or genera of rhizobia that were rescued from domesticated plant ecotypes. The analysis revealed that the bacterium by itself is incapable of surviving in the extreme conditions that its host plant can tolerate. When exposed to drought or alkaline condition, the bacterium depends on its host to survive. Data are consistent with the view of the plant phenotype as the primary factor enabling symbiotic nitrogen fixing bacteria to survive in otherwise limiting environments.

  15. Genetic and symbiotic diversity of nitrogen-fixing bacteria isolated from agricultural soils in the western Amazon by using cowpea as the trap plant.

    Science.gov (United States)

    Azarias Guimarães, Amanda; Duque Jaramillo, Paula Marcela; Simão Abrahão Nóbrega, Rafaela; Florentino, Ligiane Aparecida; Barroso Silva, Karina; de Souza Moreira, Fatima Maria

    2012-09-01

    Cowpea is a legume of great agronomic importance that establishes symbiotic relationships with nitrogen-fixing bacteria. However, little is known about the genetic and symbiotic diversity of these bacteria in distinct ecosystems. Our study evaluated the genetic diversity and symbiotic efficiencies of 119 bacterial strains isolated from agriculture soils in the western Amazon using cowpea as a trap plant. These strains were clustered into 11 cultural groups according to growth rate and pH. The 57 nonnodulating strains were predominantly fast growing and acidifying, indicating a high incidence of endophytic strains in the nodules. The other 62 strains, authenticated as nodulating bacteria, exhibited various symbiotic efficiencies, with 68% of strains promoting a significant increase in shoot dry matter of cowpea compared with the control with no inoculation and low levels of mineral nitrogen. Fifty genotypes with 70% similarity and 21 genotypes with 30% similarity were obtained through repetitive DNA sequence (BOX element)-based PCR (BOX-PCR) clustering. The 16S rRNA gene sequencing of strains representative of BOX-PCR clusters showed a predominance of bacteria from the genus Bradyrhizobium but with high species diversity. Rhizobium, Burkholderia, and Achromobacter species were also identified. These results support observations of cowpea promiscuity and demonstrate the high symbiotic and genetic diversity of rhizobia species in areas under cultivation in the western Amazon.

  16. Diversification of nitrogen fixing bacterial community using nifH gene as a biomarker in different geographical soils of Western Indian Himalayas.

    Science.gov (United States)

    Singh, Chhug; Soni, Ravindra; Jain, Sourabh; Roy, Subhadip; Goel, Reeta

    2010-09-01

    Six soil samples (Pantnagar, Chamoli, Almora, Ranichauri, Pithoragarh and Badrinath) belonging to different geographical locations of Western Himalayas in India, were analyzed to diversify the nitrogen fixing bacterial community using nifH gene biomarker DNA from soil samples were isolated and amplified using nifH gene specific primers. Genomic DNA and PCR amplified products were then individually subjected to restriction digestion with tetra to octacutter enzymes (AluI, MspI, BgIII, XbaI, HindIII, HaeIII, AluI, MspI and PasI. Further restriction pattern was studied by preparing dendograms on the basis of similarity matrix and compared for the nifH community. It was observed that temperate region soils (Ranichauri and Pithoragarh) were negative for nifH marker while subalpine region (Badrinath) and tarai region soils (Pantnagar) documented similar nifH community. Moreover; the direct genomic DNA restriction analysis indicated that subalpine region soil (Badrinath) was most diversified.

  17. Identification of a cis-acting element in nitrogen fixation genes recognized by CnfR in the nonheterocystous nitrogen-fixing cyanobacterium Leptolyngbya boryana.

    Science.gov (United States)

    Tsujimoto, Ryoma; Kamiya, Narumi; Fujita, Yuichi

    2016-08-01

    The filamentous cyanobacterium Leptolyngbya boryana has the ability to fix nitrogen without any heterocysts under microoxic conditions. Previously, we identified the cnfR gene for a master transcriptional activator for nitrogen fixation (nif) genes in a 50-kb gene cluster containing nif and nif-related genes in L. boryana. We showed that CnfR activates the transcription of nif genes in response to low oxygen conditions, which allows the oxygen-vulnerable enzyme nitrogenase to function. However, the regulatory mechanism that underlies regulation by CnfR remains unknown. In this study, we identified a conserved cis-acting element that is recognized by CnfR. We established a reporter system in the non-diazotrophic cyanobacterium Synechocystis sp. PCC 6803 using luciferase genes (luxAB). Reporter analysis was performed with a series of truncated and modified upstream regulatory regions of nifB and nifP. The cis-element can be divided into nine motifs I-IX, and it is located 76 bp upstream of the transcriptional start sites of nifB and nifP. Six motifs of them are essential for transcriptional activation by CnfR. This cis-acting element is conserved in the upstream regions of nif genes in all diazotrophic cyanobacteria, including Anabaena and Cyanothece, thereby suggesting that the transcriptional regulation by CnfR is widespread in nitrogen-fixing cyanobacteria.

  18. Biochemical and Molecular Phylogenetic Study of Agriculturally Useful Association of a Nitrogen-Fixing Cyanobacterium and Nodule Sinorhizobium with Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    E. V. Karaushu

    2015-01-01

    Full Text Available Seed inoculation with bacterial consortium was found to increase legume yield, providing a higher growth than the standard nitrogen treatment methods. Alfalfa plants were inoculated by mono- and binary compositions of nitrogen-fixing microorganisms. Their physiological and biochemical properties were estimated. Inoculation by microbial consortium of Sinorhizobium meliloti T17 together with a new cyanobacterial isolate Nostoc PTV was more efficient than the single-rhizobium strain inoculation. This treatment provides an intensification of the processes of biological nitrogen fixation by rhizobia bacteria in the root nodules and an intensification of plant photosynthesis. Inoculation by bacterial consortium stimulates growth of plant mass and rhizogenesis and leads to increased productivity of alfalfa and to improving the amino acid composition of plant leaves. The full nucleotide sequence of the rRNA gene cluster and partial sequence of the dinitrogenase reductase (nifH gene of Nostoc PTV were deposited to GenBank (JQ259185.1, JQ259186.1. Comparison of these gene sequences of Nostoc PTV with all sequences present at the GenBank shows that this cyanobacterial strain does not have 100% identity with any organisms investigated previously. Phylogenetic analysis showed that this cyanobacterium clustered with high credibility values with Nostoc muscorum.

  19. Expression profile analysis of the oxygen response in the nitrogen-fixing Pseudomonas stutzeri A1501 by genome-wide DNA microarray

    Institute of Scientific and Technical Information of China (English)

    DOU YueTan; YAN YongLiang; PING ShuZhen; LU Wei; CHEN Ming; ZHANG Wei; WANG YiPing; JIN Qi; LIN Min

    2008-01-01

    Pseudomonas stutzeri A1501, an associative nitrogen-fixing bacterium, was isolated from the rice paddy rhizosphere. This bacterium fixes nitrogen under microaerobic conditions. In this study, ge-nome-wide DNA microarrays were used to analyze the global transcription profile of A1501 under aerobic and microaerobic conditions. The expression of 135 genes was significantly altered by more than 2-fold in response to oxygen stress. Among these genes, 68 were down-regulated under aerobic conditions; these genes included those responsible for nitrogen fixation and denitrification. Sixty-seven genes were up-regulated under aerobic conditions; these genes included sodC, encoding a copper-zinc superoxide dismutase, PST2179, encoding an NAD(P)-dependent oxidoreductase, PST3584, encoding a 2OG-Fe(Ⅱ) oxygenase, and PST3602, encoding an NAD(P)H-flavin oxidoreductase. Addi-tionally, seven genes involved in capsular polysaccharide and antigen oligosaccharide biosynthesis together with 17 genes encoding proteins of unknown function were up-regulated under aerobic con-ditions. The overall analysis suggests that the genes we identified are involved in the protection of the bacterium from oxygen, but the mechanisms of their action remain to be elucidated.

  20. GroEL of the nitrogen-fixing cyanobacterium Anabaena sp. strain L-31 exhibits GroES and ATP-independent refolding activity.

    Science.gov (United States)

    Potnis, Akhilesh A; Rajaram, Hema; Apte, Shree K

    2016-03-01

    The nitrogen-fixing cyanobacterium, Anabaena L-31 has two Hsp60 proteins, 59 kDa GroEL coded by the second gene of groESL operon and 61 kDa Cpn60 coded by cpn60 gene. Anabaena GroEL formed stable higher oligomer (>12-mer) in the presence of K(+) and prevented thermal aggregation of malate dehydrogenase (MDH). Using three protein substrates (MDH, All1541 and green fluorescent protein), it was found that the refolding activity of Anabaena GroEL was lower than that of Escherichia coli GroEL, but independent of both GroES and ATP. This correlated with in vivo data. GroEL exhibited ATPase activity which was enhanced in the presence of GroES and absence of a denatured protein, contrary to that observed for bacterial GroEL. However, a significant role for ATP could not be ascertained during in vitro folding assays. The monomeric Cpn60 exhibited much lower refolding activity than GroEL, unaffected by GroES and ATP. In vitro studies revealed inhibition of the refolding activity of Anabaena GroEL by Cpn60, which could be due to their different oligomeric status. The role of GroES and ATP may have been added during the course of evolution from the ancient cyanobacteria to modern day bacteria enhancing the refolding ability and ensuring wider scope of substrates for GroEL.

  1. Sucrose synthesis in the nitrogen-fixing Cyanobacterium Anabaena sp. strain PCC 7120 is controlled by the two-component response regulator OrrA.

    Science.gov (United States)

    Ehira, Shigeki; Kimura, Satoshi; Miyazaki, Shogo; Ohmori, Masayuki

    2014-09-01

    The filamentous, nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 accumulates sucrose as a compatible solute against salt stress. Sucrose-phosphate synthase activity, which is responsible for the sucrose synthesis, is increased by salt stress, but the mechanism underlying the regulation of sucrose synthesis remains unknown. In the present study, a response regulator, OrrA, was shown to control sucrose synthesis. Expression of spsA, which encodes a sucrose-phosphate synthase, and susA and susB, which encode sucrose synthases, was induced by salt stress. In the orrA disruptant, salt induction of these genes was completely abolished. The cellular sucrose level of the orrA disruptant was reduced to 40% of that in the wild type under salt stress conditions. Moreover, overexpression of orrA resulted in enhanced expression of spsA, susA, and susB, followed by accumulation of sucrose, without the addition of NaCl. We also found that SigB2, a group 2 sigma factor of RNA polymerase, regulated the early response to salt stress under the control of OrrA. It is concluded that OrrA controls sucrose synthesis in collaboration with SigB2.

  2. Evidence of reduced poly-B-hydroxybutyrate biosynthesis in free-living nitrogen-fixing bacteria, Azotobacter chroococcum, following acquired resistance to the fungicide captan.

    Science.gov (United States)

    Miclaus, N; Vannini, C; Celano, G; Piccolo, A; Simoncini, S

    1992-08-12

    Some biological activities of Azotobacter chroococcum, strain Azcap 1, (spontaneous mutant, captan resistant up to 300 micrograms/ml) were assayed on RM medium with and without the presence of the fungicide. Comparisons were also carried out with Az. chroococcum sensitive strains Azwt, Azcan 10 and 14. The hydrolysis of captan, incorporated in agar plates of RM at 100 micrograms/ml, was rapid, since on 4-day plates, no effect was found on the strain Azwt, while on freshly prepared ones its growth was completely blocked. As for Azcap 1, grown on RM only, the behaviour was similar to that of sensitive strains, whereas when grown on captan the results of experiments showed: (i) a lag of approximately 12 h to reach the maximum nitrogen-fixing activity; (ii) delay of 12-24 h in the full consumption of glucose present in the medium, although the invertase activity did not present differences; (iii) high ATP culture content during the 50 h of the experiment; (iv) approximately 6-10-fold lower production of PHB (poly-B-hydroxybutyrate); (v) lack of typical encystment phase, for the tested 96 h and reduced viability in developing colonies on agar RM medium. In contrast, when captan was added to cultural medium at sublethal concentration, 50 micrograms/ml for sensitive strain Azwt and 200 micrograms/ml for Azcap 1, the amount of glutathione produced (to remove the fungicide toxicity) was several times higher for the former.

  3. Biochemical and Molecular Phylogenetic Study of Agriculturally Useful Association of a Nitrogen-Fixing Cyanobacterium and Nodule Sinorhizobium with Medicago sativa L.

    Science.gov (United States)

    Karaushu, E V; Lazebnaya, I V; Kravzova, T R; Vorobey, N A; Lazebny, O E; Kiriziy, D A; Olkhovich, O P; Taran, N Yu; Kots, S Ya; Popova, A A; Omarova, E; Koksharova, O A

    2015-01-01

    Seed inoculation with bacterial consortium was found to increase legume yield, providing a higher growth than the standard nitrogen treatment methods. Alfalfa plants were inoculated by mono- and binary compositions of nitrogen-fixing microorganisms. Their physiological and biochemical properties were estimated. Inoculation by microbial consortium of Sinorhizobium meliloti T17 together with a new cyanobacterial isolate Nostoc PTV was more efficient than the single-rhizobium strain inoculation. This treatment provides an intensification of the processes of biological nitrogen fixation by rhizobia bacteria in the root nodules and an intensification of plant photosynthesis. Inoculation by bacterial consortium stimulates growth of plant mass and rhizogenesis and leads to increased productivity of alfalfa and to improving the amino acid composition of plant leaves. The full nucleotide sequence of the rRNA gene cluster and partial sequence of the dinitrogenase reductase (nifH) gene of Nostoc PTV were deposited to GenBank (JQ259185.1, JQ259186.1). Comparison of these gene sequences of Nostoc PTV with all sequences present at the GenBank shows that this cyanobacterial strain does not have 100% identity with any organisms investigated previously. Phylogenetic analysis showed that this cyanobacterium clustered with high credibility values with Nostoc muscorum.

  4. Selection of nitrogen-fixing deficient Burkholderia vietnamiensis strains by cystic fibrosis patients: involvement of nif gene deletions and auxotrophic mutations.

    Science.gov (United States)

    Menard, Aymeric; Monnez, Claire; Estrada de Los Santos, Paulina; Segonds, Christine; Caballero-Mellado, Jesus; Lipuma, John J; Chabanon, Gerard; Cournoyer, Benoit

    2007-05-01

    Burkholderia vietnamiensis is the third most prevalent species of the Burkholderia cepacia complex (Bcc) found in cystic fibrosis (CF) patients. Its ability at fixing nitrogen makes it one of the main Bcc species showing strong filiations with environmental reservoirs. In this study, 83% (29 over 35) of the B. vietnamiensis CF isolates and 100% of the environmental ones (over 29) were found expressing the dinitrogenase complex (encoded by the nif cluster) which is essential in N(2) fixation. Among the deficient strains, two were found growing with ammonium chloride suggesting that they were defective in N(2) fixation, and four with amino acids supplements suggesting that they were harbouring auxotrophic mutations. To get insights about the genetic events that led to the emergence of the N(2)-fixing defective strains, a genetic analysis of B. vietnamiensis nitrogen-fixing property was undertaken. A 40-kb-long nif cluster and nif regulatory genes were identified within the B. vietnamiensis strain G4 genome sequence, and analysed. Transposon mutagenesis and nifH genetic marker exchanges showed the nif cluster and several other genes like gltB (encoding a subunit of the glutamate synthase) to play a key role in B. vietnamiensis ability at growing in nitrogen-free media. nif cluster DNA probings of restricted genomic DNA blots showed a full deletion of the nif cluster for one of the N(2)-fixing defective strain while the other one showed a genetic organization similar to the one of the G4 strain. For 17% of B. vietnamiensis clinical strains, CF lungs appeared to have favoured the selection of mutations or deletions leading to N(2)-fixing deficiencies.

  5. A mutant GlnD nitrogen sensor protein leads to a nitrogen-fixing but ineffective Sinorhizobium meliloti symbiosis with alfalfa.

    Science.gov (United States)

    Yurgel, Svetlana N; Kahn, Michael L

    2008-12-02

    The nitrogen-fixing symbiosis between rhizobia and legume plants is a model of coevolved nutritional complementation. The plants reduce atmospheric CO(2) by photosynthesis and provide carbon compounds to symbiotically associated bacteria; the rhizobia use these compounds to reduce (fix) atmospheric N(2) to ammonia, a form of nitrogen the plants can use. A key feature of symbiotic N(2) fixation is that N(2) fixation is uncoupled from bacterial nitrogen stress metabolism so that the rhizobia generate "excess" ammonia and release this ammonia to the plant. In the symbiosis between Sinorhizobium meliloti and alfalfa, mutations in GlnD, the major bacterial nitrogen stress response sensor protein, led to a symbiosis in which nitrogen was fixed (Fix(+)) but was not effective (Eff(-)) in substantially increasing plant growth. Fixed (15)N(2) was transported to the shoots, but most fixed (15)N was not present in the plant after 24 h. Analysis of free-living S. meliloti strains with mutations in genes related to nitrogen stress response regulation (glnD, glnB, ntrC, and ntrA) showed that catabolism of various nitrogen-containing compounds depended on the NtrC and GlnD components of the nitrogen stress response cascade. However, only mutants of GlnD with an amino terminal deletion had the unusual Fix(+)Eff(-) symbiotic phenotype, and the data suggest that these glnD mutants export fixed nitrogen in a form that the plants cannot use. These results indicate that bacterial nitrogen stress regulation is important to symbiotic productivity and suggest that GlnD may act in a novel way to influence symbiotic behavior.

  6. Uptake and Requirements of Molybdenum and Vanadium in Nitrogen Fixing Bacteria: Implications for the Nitrogen Cycle Now and in the Past.

    Science.gov (United States)

    Bellenger, J.; Wichard, T.; Kraepiel, A. M.

    2008-12-01

    Three nitrogenases (Mo-, V- and Fe-Nase) have thus far been identified. The requirement and use efficiency of those metals are key parameters for the nitrogen cycle. Within present terrestrial ecosystems, the Mo- Nase is considered to be dominant and the so called alternative nitrogenases (V- and Fe-Nase) have heretofore been neglected, likely resulting in misconceptions about the soil nitrogen cycle. Here, I present an overview of recent findings on trace metals speciation in soils and requirements, homeostasis, and uptake of these metals by free-livng nitrogen fixing bacteria. Our data show that Mo in soils associates strongly with organic matter, contrary to the classic view of Mo being associated with iron oxides. We also find that free- living nitrogen fixers, such as Azotobacter vinelandii, acquire both Mo and V through highly regulated uptake systems using released ligands specifically targeting the required metals, similar to that of iron. Finally, our findings demonstrate that nitrogen fixers, e.g. A. vinelandii, use Mo and V to fix nitrogen with close efficiency. This, and recent work showing that Mo may be limiting N2 fixation in a variety of terrestrial systems suggest that the worldwide dominance of Mo-nitrogenase may have been overestimated, and the role of the alternative nitrogenases in present environments deserves more attention. Interestingly, two decades after the identification of the alternative V and Fe nitrogenases, their evolution and exact role in the terrestrial nitrogen cycle over geologic time are still unclear. As crustal V abundance is about 100 times higher than Mo, nitrogen fixers might have benefited throughout geologic time from being able to utilize this additional metal source to sustain nitrogen fixation. A better understanding of the past and present nitrogen cycle is critical to anticipate the possible responses of terrestrial environments to global changes due to recent and future anthropic activities.

  7. Effect of abandonment on diversity and abundance of free-living nitrogen-fixing bacteria and total bacteria in the cropland soils of Hulun Buir, Inner Mongolia.

    Directory of Open Access Journals (Sweden)

    Huhe

    Full Text Available In Inner Mongolia, steppe grasslands face desertification or degradation because of human over activity. One of the reasons for this condition is that croplands have been abandoned after inappropriate agricultural management. The soils in these croplands present heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, we assessed the molecular ecology of total and free-living nitrogen-fixing bacterial communities in soils from steppe grasslands and croplands that were abandoned for different periods (1, 5, and 25 years and compared the degree of recovery. The abandoned croplands included in the study were natural restoration areas without human activity. Denaturing gradient gel electrophoresis and quantitative PCR (qPCR were used to analyze the nifH and 16S rRNA genes to study free-living diazotrophs and the total bacterial community, respectively. The diversities of free-living nitrogen fixers and total bacteria were significantly different between each site (P<0.001. Neither the total bacteria nor nifH gene community structure of a cropland abandoned for 25 years was significantly different from those of steppe grasslands. In contrast, results of qPCR analysis of free-living nitrogen fixers and total bacteria showed significantly high abundance levels in steppe grassland (P<0.01 and P<0.03, respectively. In this study, the microbial communities and their gene abundances were assessed in croplands that had been abandoned for different periods. An understanding of how environmental factors and changes in microbial communities affect abandoned croplands could aid in appropriate soil management to optimize the structures of soil microorganisms.

  8. Cellvibrio diazotrophicus sp. nov., a nitrogen-fixing bacteria isolated from the rhizosphere of salt meadow plants and emended description of the genus Cellvibrio.

    Science.gov (United States)

    Suarez, Christian; Ratering, Stefan; Kramer, Irina; Schnell, Sylvia

    2014-02-01

    Two Gram-reaction-negative, aerobic, nitrogen-fixing, rod-shaped bacteria, designated strains E20 and E50(T), were isolated from the rhizosphere of salt meadow plants Plantago winteri and Hordeum secalinum, respectively, near Münzenberg, Germany. Based on the 16S rRNA gene sequence analysis both strains E20 and E50(T) are affiliated with the genus Cellvibrio, sharing the highest similarity with Cellvibrio gandavensis LMG 18551(T) (96.4%) and (97.1%), respectively. Strains E20 and E50(T) were oxidase and catalase-positive, grew at a temperature range between 16 and 37 °C and in the presence of 0-5% NaCl (w/v). The DNA G+C contents were 52.1 mol% (E20) and 51.6 mol% (E50(T)). Major fatty acids of strains E20 and E50(T) were summed feature 3 (C16 : 1ω7c and/or iso-C(15 : 0) 2-OH), C(16 : 0), C(18 : 1)ω7c, C(12 : 0), C(18 : 0) and C(12 : 0) 3-OH. The DNA-DNA relatedness of the strains to Cellvibrio gandavensis LMG 18551(T) was 39% for strain E20 and 58% for strain E50(T). The nitrogen fixation capability of strains E20 and E50(T) was confirmed by the acetylene reduction assay. On the basis of our polyphasic taxonomic study, strains E20 and E50(T) represent a novel species of the genus Cellvibrio, for which the name Cellvibrio diazotrophicus is proposed. The type strain of Cellvibrio diazotrophicus is E50(T) ( = LMG 27267(T) = KACC 17069(T)). An emended description of the genus Cellvibrio is proposed based on the capability of fixing nitrogen and growth in presence of up to 5% NaCl (w/v).

  9. Effect of abandonment on diversity and abundance of free-living nitrogen-fixing bacteria and total bacteria in the cropland soils of Hulun Buir, Inner Mongolia.

    Science.gov (United States)

    Huhe; Borjigin, Shinchilelt; Cheng, Yunxiang; Nomura, Nobukiko; Nakajima, Toshiaki; Nakamura, Toru; Uchiyama, Hiroo

    2014-01-01

    In Inner Mongolia, steppe grasslands face desertification or degradation because of human over activity. One of the reasons for this condition is that croplands have been abandoned after inappropriate agricultural management. The soils in these croplands present heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, we assessed the molecular ecology of total and free-living nitrogen-fixing bacterial communities in soils from steppe grasslands and croplands that were abandoned for different periods (1, 5, and 25 years) and compared the degree of recovery. The abandoned croplands included in the study were natural restoration areas without human activity. Denaturing gradient gel electrophoresis and quantitative PCR (qPCR) were used to analyze the nifH and 16S rRNA genes to study free-living diazotrophs and the total bacterial community, respectively. The diversities of free-living nitrogen fixers and total bacteria were significantly different between each site (Pbacteria nor nifH gene community structure of a cropland abandoned for 25 years was significantly different from those of steppe grasslands. In contrast, results of qPCR analysis of free-living nitrogen fixers and total bacteria showed significantly high abundance levels in steppe grassland (P<0.01 and P<0.03, respectively). In this study, the microbial communities and their gene abundances were assessed in croplands that had been abandoned for different periods. An understanding of how environmental factors and changes in microbial communities affect abandoned croplands could aid in appropriate soil management to optimize the structures of soil microorganisms.

  10. A mutant GlnD nitrogen sensor protein leads to a nitrogen-fixing but ineffective Sinorhizobium meliloti symbiosis with alfalfa

    Science.gov (United States)

    Yurgel, Svetlana N.; Kahn, Michael L.

    2008-01-01

    The nitrogen-fixing symbiosis between rhizobia and legume plants is a model of coevolved nutritional complementation. The plants reduce atmospheric CO2 by photosynthesis and provide carbon compounds to symbiotically associated bacteria; the rhizobia use these compounds to reduce (fix) atmospheric N2 to ammonia, a form of nitrogen the plants can use. A key feature of symbiotic N2 fixation is that N2 fixation is uncoupled from bacterial nitrogen stress metabolism so that the rhizobia generate “excess” ammonia and release this ammonia to the plant. In the symbiosis between Sinorhizobium meliloti and alfalfa, mutations in GlnD, the major bacterial nitrogen stress response sensor protein, led to a symbiosis in which nitrogen was fixed (Fix+) but was not effective (Eff−) in substantially increasing plant growth. Fixed 15N2 was transported to the shoots, but most fixed 15N was not present in the plant after 24 h. Analysis of free-living S. meliloti strains with mutations in genes related to nitrogen stress response regulation (glnD, glnB, ntrC, and ntrA) showed that catabolism of various nitrogen-containing compounds depended on the NtrC and GlnD components of the nitrogen stress response cascade. However, only mutants of GlnD with an amino terminal deletion had the unusual Fix+Eff− symbiotic phenotype, and the data suggest that these glnD mutants export fixed nitrogen in a form that the plants cannot use. These results indicate that bacterial nitrogen stress regulation is important to symbiotic productivity and suggest that GlnD may act in a novel way to influence symbiotic behavior. PMID:19020095

  11. Antimicrobial-resistant faecal organisms in algae products marketed as health supplements

    LENUS (Irish Health Repository)

    2017-09-01

    Dietary supplements are increasingly popular in Irish society. One of these is blue-green algae which is used with a variety health benefits in mind. A batch of Chlorella powder was found to be contaminated with Salmonella species in Ireland in 2015. This prompted additional testing of a total of 8 samples of three different products (Chlorella, Spirulina and Super Greens), for other faecal flora and antimicrobial resistance in any bacteria isolated. All 8 samples cultured enteric flora such as Enterococci, Enterobacteriaceae and Clostridium species. Antimicrobial susceptibility testing revealed one isolate with extended-spectrum β-lactamase (ESBL) activity and one with carbapenemase activity. Clinicians caring for vulnerable patients should be aware of the potential risk of exposure to antimicrobial resistant bacteria associated with these products

  12. Final Report: The Rhizosphere Association of the Nitrogen Fixing Bacterial Species Azotobacter Paspali with the Tropical Grass Paspalum Notatum: Specificity of Colonization and Contribution to Plant Nutrition, July 1, 1995 - February 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Christina K.

    1997-02-14

    The nitrogen fixing bacterium azotobacter paspali was first isolated from the roots of the sub-tropical grass, palpium notatum, and added to the clenus in 1996, by Dr. J. Dobereiner (Brazil). It is mentioned that this root association bacteria shows remarkable signs of host-plant specificity to one eco-type of this grass. This specificity is rare in non-symbiotic plant microbe interactions so far identified.

  13. Magnetic separation of algae

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  14. Next generation paradigm for urban pluvial flood modelling, prediction, management and vulnerability reduction - Interaction between RainGain and Blue Green Dream projects

    Science.gov (United States)

    Maksimovic, C.

    2012-04-01

    The effects of climate change and increasing urbanisation call for a new paradigm for efficient planning, management and retrofitting of urban developments to increase resilience to climate change and to maximize ecosystem services. Improved management of urban floods from all sources in required. Time scale for well documented fluvial and coastal floods allows for timely response but surface (pluvial) flooding caused by intense local storms had not been given appropriate attention, Pitt Review (UK). Urban surface floods predictions require fine scale data and model resolutions. They have to be tackled locally by combining central inputs (meteorological services) with the efforts of the local entities. Although significant breakthrough in modelling of pluvial flooding was made there is a need to further enhance short term prediction of both rainfall and surface flooding. These issues are dealt with in the EU Iterreg project Rain Gain (RG). Breakthrough in urban flood mitigation can only be achieved by combined effects of advanced planning design, construction and management of urban water (blue) assets in interaction with urban vegetated areas' (green) assets. Changes in design and operation of blue and green assets, currently operating as two separate systems, is urgently required. Gaps in knowledge and technology will be introduced by EIT's Climate-KIC Blue Green Dream (BGD) project. The RG and BGD projects provide synergy of the "decoupled" blue and green systems to enhance multiple benefits to: urban amenity, flood management, heat island, biodiversity, resilience to drought thus energy requirements, thus increased quality of urban life at lower costs. Urban pluvial flood management will address two priority areas: Short Term rainfall Forecast and Short term flood surface forecast. Spatial resolution of short term rainfall forecast below 0.5 km2 and lead time of a few hours are needed. Improvements are achievable by combining data sources of raingauge networks

  15. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta)

    Science.gov (United States)

    2016-01-01

    Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation. PMID:27642603

  16. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta

    Directory of Open Access Journals (Sweden)

    Huanyang Wu

    2016-01-01

    Full Text Available Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.

  17. Effect of Different Light Qualities on Growth, Pigment Content, Chlorophyll Fluorescence, and Antioxidant Enzyme Activity in the Red Alga Pyropia haitanensis (Bangiales, Rhodophyta).

    Science.gov (United States)

    Wu, Huanyang

    2016-01-01

    Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.

  18. 贺兰山地区油松根际固氮菌的多样性研究%Diversity of nitrogen-fixing bacteria isolated from Pinus tabulaeformis in Helan Mountains

    Institute of Scientific and Technical Information of China (English)

    牛艳芳; 陈立红; 闫伟

    2016-01-01

    The diversity and community structure of nitrogen-fixing bacteria isolated from Pinus tabulaeformis rhizosphere in Helan Mountains was studied. Nitrogen-fixing bacteria from rhizosphere soil were isolated and purified by Ashby’ s Medium,the 16S rDNA gene of nitrogen-fixing bacteria was amplified using primers 27f/1492r and sequenced,the align-ment of 16S rDNA sequences was conducted by DNAMAN 6.0,and the neighbor-joining phylogenetic tree was construc-ted by MEGA 4.0 software. The results showed that nitrogen-fixing bacteria isolated from P. tabulaeformis belonged to nine groups,which were Pseudomonas,Bacillus,Phyllobacterium,Arthrobacter,Rhizobium,Paenibacillus,Sphin-gomonas,Caulobacter,Pedobacter,and Pseudomonas,Bacillus,Phyllobacterium,Arthrobacter were dominant groups.The results indicated that nitrogen-fixing bacteria from P. tabulaeformis in Helan Mountains have rich diversity.%对贺兰山北寺自然保护区油松(Pinus tabulaeformis)的根际土壤固氮菌多样性和群落结构进行研究。采用阿须贝培养基对土壤中的固氮菌进行分离和纯化,用通用引物27f/1492r对固氮菌进行16S rDNA扩增并测序,应用DNAMAN 6.0软件进行多序列比对,用MEGA 4.0软件构建聚类树。结果表明:从贺兰山北寺油松根际土壤中分离出的固氮菌属于假单胞菌属(Pseudomonas)、芽孢杆菌属(Bacillus)、叶杆菌属(Phyllobacteri-um)、节杆菌属(Arthrobacter)、根瘤菌属(Rhizobium)、类芽孢杆菌属(Paenibacillus)、鞘氨醇单胞菌属(Sphingomonas)、柄细菌属(Caulobacter)、土地杆菌属(Pedobacter)等9个不同的类群,其中假单胞菌属(Pseudomonas)、芽孢杆菌属(Bacillus)、叶杆菌属(Phyllobacterium)、节杆菌属(Arthrobacter)是优势类群。这表明贺兰山北寺地区油松根际土壤中固氮菌具有较丰富的多样性。

  19. A light-harvesting siphonaxanthin-chlorophyll a/b-protein complex of marine green alga,Bryopsis corticulans

    Institute of Scientific and Technical Information of China (English)

    CHEN Hui; SHEN Shihua; HE Junfang; LENG Jing; LI Liangbi; KUANG Tingyun

    2004-01-01

    A light-harvesting chlorophyll a/b-protein complex (LHCP) was isolated directly from thylakoid membranes of marine green alga, Bryopsis corticulans, by two consecutive runs of liquid chromatography. The trimeric form of the light-harvesting complex has been obtained by sucrose gradient ultracentrifugation. The result of SDSPAGE shows that the light-harvesting complex is composed of at least five apoproteins in which a protein with apparent molecular weight of about 31 kD was never found in the major light-harvesting complex (LHC Ⅱ) from higher plants.The isolated Bryopsis corticulans light-harvesting complex contains a specific carotenoid, siphonaxanthin, as well as chlorophyll (Chl) a, Chl b, neoxanthin and violaxanthin. Siphonaxanthin which is present in the light-harvesting siphonaxanthin-chlorophyll a/b-protein complex of Bryopsis corticulans is responsible for enhanced absorption in the blue-green region (530 nm). Efficient energy transfer from both siphonaxanthin and Chl b to Chl a in Bryopsis corticulans LHCP, which has similar absorption and fluorescence emission spectra to those of the lutein-chlorophyll a/b-protein of higher plants, proved that molecular arrangement of the light-harvesting pigments was highly ordered in the Bryopsis corticulans LHCP. The siphonaxanthin-chlorophyll a/b-proteins allow enhanced absorption of blue-green light, the predominant light available in deep ocean waters or shaded subtidal marine habitats.

  20. Alkaloids in Marine Algae

    OpenAIRE

    Ekrem Sezik; Aline Percot; Kasım Cemal Güven

    2010-01-01

    This paper presents the alkaloids found in green, brown and red marine algae. Algal chemistry has interested many researchers in order to develop new drugs, as algae include compounds with functional groups which are characteristic from this particular source. Among these compounds, alkaloids present special interest because of their pharmacological activities. Alkaloid chemistry has been widely studied in terrestrial plants, but the number of studies in algae is insignificant. In this review...

  1. 固氮类植物的生态功能及其在生态修复中的应用%The ecological functions of nitrogen -fixing plants and their applications in ecological restoration

    Institute of Scientific and Technical Information of China (English)

    赵玉洁; 张宇清

    2012-01-01

    The nitrogen cycle which is an important step in ecological restoration processes take an irreplaceable special role in life and material circulation on earth and maintain and rebuild of degraded ecosystems. The article made a scientific review about the ecological functions of nitrogen - fixing plants and the success which they make on ameliorating the soil physical and chemical properties and promoting restoration of the ecosystems. At last the author draw the conclusion that nitrogen - fixing plants take a significant part in ecological restoration and .the full use of the nitrogen - fixing plants is an important way in vegetation recovery. In the future, more quantitative studies on nitrogen -fixing processes on terrestrial ecosystem are needed and the influential dominant factors and ecological mechanisms shall be made clear. Thus the reliable theoretical basis will be provided for the restoration in terrestrial ecosystems.%氮素循环对地球生命与物质循环系统有着不可替代的特殊作用,维护和重建退化生态系统的氮素循环成为生态修复目标的重要步骤之一。文中系统介绍了固氮类植物改善土壤理化性质、促进生态修复等方面的生态功能和相关研究成果,认为固氮类植物在生态修复中具有重要的生态作用,固氮植物的选用是植被恢复的重要技术途径。建议未来研究中,应该加强对陆地生态系统固氮过程的量化研究,确定影响共生固氮的主导因子和生态机制,从而为陆地系统的生态恢复提供更为可靠的理论依据。

  2. 氮肥对3种固氮蓝藻种群数量的影响%Study on Effect of Fertilizers in Rice Fields to Fixing Blue-green Algaes

    Institute of Scientific and Technical Information of China (English)

    王秀红; 沈健英; 陆贻通

    2006-01-01

    通过2种常用化肥对固氮鱼腥藻(Anabaena azotica Ley),球胞鱼腥藻(Anabaena sphaerica Born),多变鱼腥藻(Anabaena variabilio Kutzing)影响的研究.结果表明,尿素和碳酸氢铵在低浓度(20 mg/L以下)表现为促进,当浓度为80 mg/L时,则显著抑制其种群生长;且高浓度时,尿素和碳酸氢铵对3种藻产生较强影响,处理96 h时的EC50值分别为54.0,67.0,85.7 mg/L及73.7,63.1,92.2 mg/L.

  3. 稻田除草剂对固氮蓝藻的毒性研究%Study on Herbicides in Rice Fields to Toxicity of Fixing Blue- green Algaes

    Institute of Scientific and Technical Information of China (English)

    王秀红; 沈健英; 陆贻通

    2004-01-01

    通过4种稻田除草剂对固氮鱼腥藻(Anabaena azotica Ley)、球胞鱼腥藻(Anabaena sphaerica Bom)、多变鱼腥藻(Anabaena variabilio Kutzing)的毒性进行了研究.结果表明,二甲四氯对3种藻的生长有促进作用,而丁草胺和乙草胺在低浓度(8 mg·L-1以下)表现为促进,当浓度为16 mg·L-1时,则显著抑制其生长,且高浓度时对3种藻产生较强毒性,处理96h时的EC50值分别为12.87、25.36、20.21 mg·L-1及50.52、18.37、45.43mg·L-1.3种藻对扑草净极为敏感,在低浓度时其生长受到严重抑制,继而迅速死亡.因此选择对固氮蓝藻安全的稻田除草剂,对维护稻田生态、促进农业可持续发展具有重要意义.

  4. Pollution by Blue-green Algae (Cyanophyta) in Reservoirs of Guangdong Province and Water Quality Evaluation%广东省水库的蓝藻污染状况与水质评价

    Institute of Scientific and Technical Information of China (English)

    王朝晖; 林秋奇; 胡韧; 范春雷; 韩博平

    2004-01-01

    于2000年的丰水期和枯水期对广东省19个大中型水库的浮游植物状况进行了调查,并根据浮游植物群落结构、多样性指数、蓝藻污染状况和营养状态指数对水库的水质进行了分析.结果表明,大部分水库为蓝藻型水体,优势种类主要是能产生毒素的微囊藻类,而且蓝藻种类数和细胞密度与水库水质密切相关.蓝藻细胞密度和百分比分别为0.1×104-6728.4×104cellsL-1和0.53%-99.2%.大部分水库受到了一定程度的污染,属于中营养型;东江流域的新丰江水库和白盘珠水库水质优良,为贫营养型;而位于经济较发达的沿海地区的鹤地水库、石岩水库和契爷石水库已受到严重污染.东江流域和北江流域水库水质普遍较好,而粤西沿海地区和珠江三角洲地区水库则污染较为严重.

  5. 北京城市河湖营养状态与蓝藻水华研究%On nutritional status and blue-green algae water bloom of urban rivers and lakes in Beijing

    Institute of Scientific and Technical Information of China (English)

    刘靖; 杜桂森; 武佃卫; 吴玉梅; 杨忠山; 华振玲

    2006-01-01

    2003-2004年的调研结果显示,北京城市河湖(长河水系)总氮平均含量为1.667 mg/L,总磷平均含量为0.144 mg/L,浮游藻类平均细胞密度为41 150×104/L,其中蓝藻占90.0%.浮游藻类的群落结构为蓝藻(Cyanophyta)-绿藻(Chlorophyta)型,河湖水体中营养盐与初级生产力的关系为浮游藻类响应型,连续两年发生以微囊藻(Microcystis)占优势的蓝藻水华.河湖水体5项指标(SD、TP、TN、CODMn、Chla)的TSIM值在57~87间,水体已达到富营养或重富营养程度.其主要原因是:1)营养盐和有机物的污染;2)北京市淡水资源紧缺,补给城市河湖水量少;3)在河湖水系治理中,底部硬化,两侧(或周围)衬砌,破坏了水体的自然生态系统,使其自净能力大大降低.

  6. Fermentation of Bacillus thuringiensis based biopesticide using mud of blue-green algae%利用新鲜蓝藻藻泥发酵制备苏云金芽胞杆菌杀虫剂

    Institute of Scientific and Technical Information of China (English)

    谭超; 张乃明

    2014-01-01

    富营养化湖泊中蓝藻爆发已成突出的环境问题.以云南昆明滇池蓝藻新鲜藻泥为培养基,通过接种Bt菌种,测定发酵过程中Bt的活菌数及芽胞数,观察其生长过程中形态变化,同时测定杀虫晶体蛋白产量及杀虫毒力效价,并与常规LB培养基比较,探究了利用蓝藻藻泥培养基接种苏云金芽胞杆菌(Bt GIM1.32)制备生物源杀虫剂的可行性.结果表明:Bt GIM1.32菌种在新鲜蓝藻培养基中能正常生长并完成芽胞和伴胞晶体的合成;当蓝藻含固率为3%、pH 7、接种活化10 h处于对数生长期的菌种、接种量为2%、培养温度为30℃时,灭菌后直接接种Bt GIM1.32菌株,发酵48 h左右其活菌数可达到相对稳定值(6.79×108 CFU/mL),54 h左右芽胞数达到相对稳定值(7.01×108 CFU/mL);其130 ku晶体蛋白的质量浓度为4.81 mg/mL,对3龄小菜蛾的致死中浓度(LC50)为0.180 μL/mL,毒力效价为1 600.00 IU/μL;发酵性能较常规LB培养基优良.研究表明,蓝藻作为发酵生产生物源农药Bt的培养基具有很好的开发潜力和应用前景.

  7. Mass Spectral Investigation on Toxins. I. Isolation, Purification, and Characterization of Hepatotoxins from Freshwater Blue-Green Algae (Cyanobacteria) by High-Performance Liquid Chromatography and Fast Atom Bombardment Mass Spectrometric Techniques.

    Science.gov (United States)

    1986-09-01

    analysis ’" methods in environmental samples. The hepatotoxins from laboratory cultures of M. aeruginosa Strain 7820,15 Anabena flos- aguae (A. 4flos...flos- aguae S-23-g-1l (8 lug) F1 The results from the amino acid analysis using the Llqui-Mat Analyzer are listed in Table 2. The elution times of the...Runnegar, M.T.C., and Huynh, V.L. Effec- tiveness of Activated Carbon in the Removal of Algal Toxin from Potable Water Supplies: A Pilot Plant

  8. 苏铁类珊瑚根内藻胞层的解剖观察%The Anatomical Observation about the Cell Layer with Blue-green Algae in the Coralloid Root of Cycads

    Institute of Scientific and Technical Information of China (English)

    苏建英; 李楠; 廖芬

    2007-01-01

    通过对苏铁类隶属10属,25种植物的珊瑚根进行了解剖观察,本文主要从解剖学角度阐述了苏铁类珊瑚根中共生藻的侵染途径、部位、以及藻胞层的发生发展,并根据观察结果分析讨论其共生藻与苏铁类根的共生关系.

  9. Algae Derived Biofuel

    Energy Technology Data Exchange (ETDEWEB)

    Jahan, Kauser [Rowan Univ., Glassboro, NJ (United States)

    2015-03-31

    One of the most promising fuel alternatives is algae biodiesel. Algae reproduce quickly, produce oils more efficiently than crop plants, and require relatively few nutrients for growth. These nutrients can potentially be derived from inexpensive waste sources such as flue gas and wastewater, providing a mutual benefit of helping to mitigate carbon dioxide waste. Algae can also be grown on land unsuitable for agricultural purposes, eliminating competition with food sources. This project focused on cultivating select algae species under various environmental conditions to optimize oil yield. Membrane studies were also conducted to transfer carbon di-oxide more efficiently. An LCA study was also conducted to investigate the energy intensive steps in algae cultivation.

  10. in-silico analysis suggests alterations in the function of XisA protein as a possible mechanism of butachlor toxicity in the nitrogen fixing cyanobacterium Anabaena sp. PCC 7120.

    Science.gov (United States)

    Singh, Shilpi; Singh, Prem Pal

    2013-01-01

    Butachlor, a commonly used herbicide adversely affects the nitrogen fixing capability of Anabaena, an acclaimed nitrogen fixer in the Indian paddy fields. The nitrogen fixation in Anabaena is triggered by the excision of nifD element by xisA gene leading to rearrangement of nifD forming nifHDK operon in the heterocyst of Anabaena sp. PCC7120. Functional elucidation adjudged through in-silico analysis revealed that xisA belongs to integrase family of tyrosine recombinase. The predicted functional partners with XisA protein that have shown cooccurence with this protein in a network are mainly hypothetical proteins with unknown functions except psaK1 whose exact function in photosystem I is not yet known. The focus of this study was to find out the relation between XisA and butachlor using in-silico approaches. The XisA protein was modeled and its active sites were identified. Docking studies revealed that butachlor binds at the active site of XisA protein hampering its excision ability vis-à-vis nif genes in Anabaena sp. PCC7120. This study reveals that butachlor is not directly involved in hampering the nitrogen fixing ability of Anabaena sp. PCC7120 but by arresting the excision ability of XisA protein necessary for the functioning of nif gene and nitrogen fixation.

  11. 蓝绿激光在水下航行器导航中的应用展望%Prospects of Blue-green Laser in the Navigation of Remote Underwater Vehicle

    Institute of Scientific and Technical Information of China (English)

    张礴; 顾李冯

    2011-01-01

    针对水下航行器导航的薄弱环节,提出运用蓝绿激光的特殊性质,从远程水下航行器自身出发,对以海底地形匹配导航作为惯性导航的补充的导航方式进行了讨论.%For resolving the existing weak links of remote underwater vehicle, writer put forward that underwater vehicle start from itself, by use of the special nature of blue - green laser, sealed terrain matching navigation with inertial navigation as a supplementary means of navigation in this article.

  12. Wastewater treatment with algae

    Energy Technology Data Exchange (ETDEWEB)

    Wong Yukshan [Hong Kong Univ. of Science and Technology, Kowloon (China). Research Centre; Tam, N.F.Y. [eds.] [City Univ. of Hong Kong, Kowloon (China). Dept. of Biology and Chemistry

    1998-05-01

    Immobilized algal technology for wastewater treatment purposes. Removal of copper by free and immobilized microalga, Chlorella vulgaris. Biosorption of heavy metals by microalgae in batch and continuous systems. Microalgal removal of organic and inorganic metal species from aqueous solution. Bioaccumulation and biotransformation of arsenic, antimony and bismuth compounds by freshwater algae. Metal ion binding by biomass derived from nonliving algae, lichens, water hyacinth root and spagnum moss. Metal resistance and accumulation in cyanobacteria. (orig.)

  13. Algae fuels : a tantalizing alternative

    Energy Technology Data Exchange (ETDEWEB)

    Granson, E.

    2010-11-15

    This article surveyed the current state of research and development in the area of algae use as a basis for fuel and as a feedstock for the chemical industry. The constraints inhibiting the commercialization of algae-related processes were discussed and a brief overview of the history of algae research was presented. Interest in algae research has ebbed and flowed in conjunction with economic and social concerns. It is unknown whether algae can be grown on a scale and cost that is commercially viable. A bench-scale algae cultivation system involving photobioreactors was described. Algae are increasingly being used in treating wastewater from industrial processes, as algae can reduce ammonia and phosphate loads in effluent. Exhaust carbon dioxide is being used to feed algae crops. Advances are needed to make turning algae oil into fuel cost effective. A bench-stage process for extracting algae oil from water for biofuel conversion was described. The process results in easier-to-dry biomass without using chemical solvents or centrifuges. Algae biomass is also being explored for used as a polymer feedstock. Algae can be grown anywhere there is sun, but the challenge is in developing a large enough supply of algae biomass. Second generation algae plastic products will be more complex and may involve the creation of a monomer out of algae itself, which could make algae competitive with oil in the plastics industry. Skeptics doubt that algae processes can be commercialized, but some within the industry believe that algae biomass will eventually work within the norms of industrial processes. 5 figs.

  14. Elucidation of the 3-O-deacylase gene, pagL, required for the removal of primary β-hydroxy fatty acid from the lipid A in the nitrogen-fixing endosymbiont Rhizobium etli CE3.

    Science.gov (United States)

    Brown, Dusty B; Muszynski, Artur; Salas, Omar; Speed, Kacie; Carlson, Russell W

    2013-04-26

    Until now, the gene responsible for the 3-O-deacylation of lipid A among nitrogen-fixing endosymbionts has not been characterized. Several Gram-negative animal pathogens such as Salmonella enterica, Pseudomonas aeruginosa, and Bordetella bronchiseptica contain an outer membrane 3-O-deacylase (PagL) that has been implicated in host immune evasion. The role of 3-O-deacylated lipid A among nitrogen-fixing endosymbionts, plant endophytes, and plant pathogens has not been studied. However, D'Haeze et al. (D'Haeze, W., Leoff, C., Freshour, G., Noel, K. D., and Carlson, R. W. (2007) J. Biol. Chem. 282, 17101-17113) reported that the lipopolysaccharide from Rhizobium etli CE3 bacteroids isolated from host bean root nodules contained exclusively tetraacylated lipid A that lacked a lipid A β-hydroxymyristyl residue, an observation that is consistent with the possibility of PagL activity being important in symbiosis. A putative pagL gene was identified in the R. etli genome sequence. With this information, we created a pagL(-) mutant strain derived from R. etli CE3. Using mass spectrometry, we demonstrated that the mutant lacks 3-O-deacylated lipid A. The parent and mutant LPS were very similar as determined by gel electrophoresis and glycosyl composition analysis using gas chromatography/mass spectrometry. However, fatty acid analysis showed that the mutant lipid A contained larger amounts of β-hydroxypentadecanoic acid than that of the parent. Furthermore, the mutant was adversely affected in establishing symbiosis with its host, Phaseolus vulgaris.

  15. Anticoagulant effect of marine algae.

    Science.gov (United States)

    Kim, Se-Kwon; Wijesekara, Isuru

    2011-01-01

    Recently, a great deal of interest has been developed in the nutraceutical and pharmaceutical industries to isolate natural anticoagulant compounds from marine resources. Among marine resources, marine algae are valuable sources of novel bioactive compounds with anticoagulant effect. Phlorotannins and sulfated polysaccharides such as fucoidans in brown algae, carrageenans in red algae, and ulvans in green algae have been recognized as potential anticoagulant agents. Therefore, marine algae-derived phlorotannins and SPs have great potential for developing as anticoagulant drugs in nutraceutical and pharmaceutical areas. This chapter focuses on the potential anticoagulant agents in marine algae and presents an overview of their anticoagulant effect. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Detailed study of anaerobic digestion of Spirulina maxima algae biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.

    1986-07-01

    Biomass of the blue-green alga Spirulina maxima was converted to methane using continuous stirred tank digesters with an energy conversion efficiency of 59%. Digesters were operated using once-a-day feeding with a retention time (theta) between 5 and 40 days, volatile solid concentrations (Sto) between 20 and 100 kg VS/cubic m, and temperatures between 15 and 52/sup 0/C. The results indicated a maximum methane yield of 0.35 cubic m (STP)/kg VS added at theta = 30 days and Sto = 20 kg VS/cubic m. Under such conditions, the energy conversion of the algal biomass to methane was 59%. The maximum methane production rate of 0.80 cubic m (STP)/cubic m day was obtained with theta = 20 days and Sto = 100 kg VS/cubic m. The mesophilic condition at 35/sup 0/C produced the maximum methane yield and production rate. The process was stable and characterized by a high production of volatile acids (up to 23,200 mg/l), alkalinity (up to 20,000 mg/l), and ammonia (up to 7000 mg/l), and the high protein content of the biomass produced a well-buffered environment which reduced inhibitory effects. At higher loading rates, the inhibition of methanogenic bacteria was observed, but there was no clear-cut evidence that such a phenomenon was due to nonionized volatile acids or gaseous ammonia. The kinetic analysis using the model proposed by Chen and Hashimoto indicated that the minimum retention time was seven days. The optimum retention time increased gradually from 11 to 16 days with an increase in the initial volatile solid concentration. The kinetic constant K decreased with the improvement in the digester performance and increased in parallel with the ammonia concentration in the culture media. 32 references.

  17. Controllable optical modulation of blue/green up-conversion fluorescence from Tm3+ (Er3+) single-doped glass ceramics upon two-step excitation of two-wavelengths

    Science.gov (United States)

    Chen, Zhi; Kang, Shiliang; Zhang, Hang; Wang, Ting; Lv, Shichao; Chen, Qiuqun; Dong, Guoping; Qiu, Jianrong

    2017-04-01

    Optical modulation is a crucial operation in photonics for network data processing with the aim to overcome information bottleneck in terms of speed, energy consumption, dispersion and cross-talking from conventional electronic interconnection approach. However, due to the weak interactions between photons, a facile physical approach is required to efficiently manipulate photon-photon interactions. Herein, we demonstrate that transparent glass ceramics containing LaF3: Tm3+ (Er3+) nanocrystals can enable fast-slow optical modulation of blue/green up-conversion fluorescence upon two-step excitation of two-wavelengths at telecom windows (0.8-1.8 μm). We show an optical modulation of more than 1500% (800%) of the green (blue) up-conversion fluorescence intensity, and fast response of 280 μs (367 μs) as well as slow response of 5.82 ms (618 μs) in the green (blue) up-conversion fluorescence signal, respectively. The success of manipulating laser at telecom windows for fast-slow optical modulation from rear-earth single-doped glass ceramics may find application in all-optical fiber telecommunication areas.

  18. 农田环境中固氮菌的促生潜能与分布特点%Growth Promotion Potential and Distribution Features of Nitrogen-Fixing Bacteria in Field Environments

    Institute of Scientific and Technical Information of China (English)

    孙建光; 胡海燕; 刘君; 陈倩; 高淼; 徐晶; 周义清

    2012-01-01

    [目的]了解小麦、水稻、玉米、蔬菜等作物根际固氮菌的优势种群、固氮菌菌株的固氮、抗病、促生潜能以及菌株在系统发育地位和来源作物种类上的分布特点.[方法]采用无氮培养基培养固氮菌,乙炔还原法测定菌株固氮酶活性,平板对峙法测定菌株拮抗病原真菌性能,ACC(1-氨基环丙烷-1-羧酸)唯一氮源法定性测定菌株产ACC脱氨酶特性,比色法定量测定ACC脱氨酶活性,通过16S rDNA序列测定和相似性分析研究菌株的分类地位.[结果] 94株供试菌株的固氮酶活性在0.99-180.59nmol C2H4/h·mg蛋白,其中大于10 nmol C2H4/h·mg蛋白的菌株有42株,占全部供试菌株的44.7%;类芽孢杆菌属(Paenibacillus)和芽孢杆菌属(Bacillus)是主要类群,分别占供试菌株总数的33.0%和26.6%,且不具有寄主专一性.供试菌株中有6株分别对核盘菌(Sclerotinia sclerotiorum)、玉米赤霉菌(Gibberella zeae)和大丽轮枝菌(Verticillium dahliae)3种植物病原真菌表现出拮抗作用,占菌株总数的6.4%,抑菌率为23.9%-65.9%.有20株固氮菌能够产生ACC脱氨酶,占全部供试菌株的21.3%,活性在0.33-21.98 μmolα-丁酮酸、h·mg蛋白,主要分布在芽孢杆菌属、类芽孢杆菌属和根瘤菌属(Rhizobium).[结论]小麦、水稻、玉米、白菜、芹菜等作物根际以及农田环境中固氮菌的优势种群为类芽孢杆菌属和芽孢杆菌属,多数固氮菌菌株具有较高的固氮潜能,部分菌株具有ACC脱氨酶活性和促生潜能,少数菌株具有抗病潜能;固氮、抗病、促生潜力菌株主要分布在类芽孢杆菌属、芽孢杆菌属和根瘤菌属,随作物分布广泛,无专一性.%[Objective! The objective of this experiment is to determine the dominant species and phylogenetic position of nitrogen fixing bacteria in crop rhizosphere and field environments, and to screen for nitrogen-fixing bacteria with growth promotion potential. [Method

  19. Isolation and functional characterizations of spinach endogenous nitrogen-fixing bacteria%菠菜内生固氮菌的分离及其功能特性研究

    Institute of Scientific and Technical Information of China (English)

    王泽; 徐齐; 袁梅; 张磊; 高淼; 孙建光

    2015-01-01

    Endogenous nitrogen-fixing bacteria have positive functions of promoting growth, pathogen prevention and biological nitrogen fixation and occupy the plant tissue which is conductive to nutrient supply and suitable micro ecological environment. In this study, seven endogenous nitrogen-fixing bacteria were isolated from the root of spinach. Among the 7 diazotrophic bac-teria, five were identified as Pseudomonas and two belonged to Rhodococcus and Flavobacterium, respecitively. The nitroge-nase activities of strain Pseudomonas sp. BC-E6 and Pseudomonas sp. BC-E8 were ( 13. 19 ± 0. 32 ) and ( 12. 11 ± 0. 96 ) C2H4 nmol/(mg protein ·h), which was significantly higher (P<0. 01) than that of Azotobacter chroococcum ACCC11104. For Strain Pseudomonas sp. BC-E7, the nitrogenase activity was (8.42 ±0.03) C2H4 nmol/(mg protein ·h), production of indole acetic acid (IAA) was (59. 58 ± 4. 15) μg/mL, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity was (5. 067 ± 0. 376) μmol/(mg protein·h), and it had the capability to antagonize the growth of Rhizoctonia solani ACCC36124, Gibberella zeae ACCC362724, Sclerotinia sclerotiorum ACCC36084 and Sclerotinia sclerotiorum ACCC36905. Strain Pseudomonas sp. BC-E7 had been a multifunctional endogenous nitrogen-fixing bacterium, which should have good application prospect.%内生固氮菌具有促生、 病原菌的防治及生物固氮等作用, 并且占据着植物组织内有利于营养供应和微环境适宜的生态位, 是重要的微生物菌种资源. 从菠菜根内分离筛选优势内生固氮菌7 株, 其中假单胞菌属( Pseudomonas) 5株, 红球菌属 ( Rhodococcus) 和黄杆菌属 ( Flavobacterium) 各1株. 菌株Pseudomonas sp. BC-E6和Pseudomonas sp. BC-E8固氮酶活性较高, 分别为 (13. 19 ± 0. 32) 和 (12. 11 ± 0. 96) C2 H4 nmol/ ( mg pro-tein·h) , 与圆褐固氮菌 ( ACCC11103 ) 的固氮酶活性具有极显著性差异 ( P <0. 01 ); 菌株 Pseudomonas sp. BC-E7

  20. Research Progress on Functional Genomics of Nitrogen-fixing Microorganisms and Industrial Development of Bio-fertilizer%根际固氮微生物功能基因组及微生物肥料研究进展

    Institute of Scientific and Technical Information of China (English)

    燕永亮; 李力; 李俊

    2011-01-01

    固氮微生物为植物提供了大量的氮素来源,开展生物固氮的研究对缓解我国粮食短缺、能源消耗、环境污染等重大社会问题具有重要意义.综述了国际上关于固氮微生物功能基因组学以及微生物肥料产业的发展状况,并以巴西、阿根廷等国家在农业生产中的节肥增产的成功经验进行了案例分析.针对目前我国微生物肥料产业的发展状况以及行业前景提出了建设性意见,认为在功能基因组学平台上加强对固氮微生物基因表达调控及与宿主互作机制的研究将为后续开发性能优良的高效固氮、综合抗逆的固氮微生物工程菌株奠定重要理论基础.%Nitrogen-fixing microorganism provides large amount of nitrogen sources to crops. It is of great significance to carry out biological nitrogen fixation research in solving great social issues of grain shortage, energy consumption and environmental pollution in China. This paper reviews the current development status on nitrogen-fixing microorganism and bio-fertilizer industry in the world, and makes case analysis on successful cases in applying bio-fertilizer during agricultural production in Brazil, Argentina and other countries. The authors also put forward constructive suggestions for the development of industrial bio-fertilizer in China, such as studies on mechanisms of nif gene expression and regulation, together with interaction of microbe-plant at the functional genomic level must be strengthened. This will lay an important theoretical basis for developing comprehensive engineering strains with high nitrogen fixation and stress tolerance ability.

  1. 山西黄芪根际固氮菌的分离与应用%Isolation and application of nitrogen-fixing bacteria in rhizosphere of Astragalus membranaceus Bunge in Shanxi

    Institute of Scientific and Technical Information of China (English)

    薛智权; 唐中伟; 李浩; 周然; 梁建萍

    2016-01-01

    [Objective]Astragalus membranaceus Bunge (AMB)is an important herb that has been used in traditional Chinese medicine for centuries,and Hunyuan County of Shanxi province is one of the most important planting bases for AMB.Nitrogen fertilizer input for AMB production in China is very high.It is essential to reduce nitrogen fertilizer in-put and thus cultivation cost while achieving a high yield for sustainable and environmentally friendly AMB production. Research on biological nitrogen fixation has increased significantly because of its potential importance to the economy and the environment.AMB plants can obtain nitrogen from biological nitrogen fixation via diazotrophs.The aim of this work was to screen and identify nitrogen-fixing bacteria from the rhizosphere of AMB cultivated in Hunyuan County, Shanxi province,and to demonstrate their potential for nitrogen fixation with AMB as well as plant growth promotion. [Methods]120 nitrogen fixing strains were isolated from soil samples using Ashby nitrogen free medium.Two strains of them,t1 6 and t21,with strong ability of nitrogen fixation were screened out according to the ability of nitrogen fixa-tion,growth speed and other characteristics in further screening with nitrogen fixing medium.To demonstrate their potential for nitrogen fixation with AMB and growth promotion activities,the bacterial liquid of the two isolates were used to soak AMB seeds and inoculate into AMB seedlings for 30 d at 28°C in a growth cabinet.[Results]Based on morphological detection,physiological and biochemical detection and 1 6S rRNA gene sequence analysis,the two strains of t1 6 and t21 were identified as Rhizobium sp.and Sinorhizobium sp.,respectively.Both of the two strains signifi-cantly promoted the growth of AMB seedlings.They also increased the nitrogen contents of dry weight by 14.23% to 18.67% and 13.10% to 18.77%,respectively,compared with the uninoculated controls.The bacterial liquids of T1 6 with 10 6 mL-1 and T21 with 10 8 m

  2. Screening and Preliminary Identification for a Strain of Nitrogen -Fixing Bacterium Producing PHB%一株产 PHB 固氮菌的筛选和初步鉴定

    Institute of Scientific and Technical Information of China (English)

    李贵正; 涂国全; 刘纪臣; 李新柱

    2015-01-01

    Eight nitrogen -fixing bacteria were isolated from the activated sludge from sewage farm of Kingenta by enriching culture and isolating in Ashby medium.Three strains producing PHB were obtained by Suda black staining.Strain N1 was regarded as the best one by the PHB diameter,content of PHB account for cell dry weight and the colony growth rate.Strain N1 was preliminary identified as Azotobacter chroococcum.%经 Ashby 培养基富集培养及平板分离,从金正大污水处理厂的活性污泥中分离到8株自生固氮菌。经苏丹黑染色初筛获得3株产 PHB 菌株。以菌株产生的 PHB 颗粒大小、PHB 占细胞干重的含量及菌落生长速度为指标,获得最佳菌株 N1。通过《伯杰氏细菌学鉴定手册》第九版初步鉴定此菌株为圆褐固氮菌(Azotobacter chroococcum)。

  3. Degradation of the neonicotinoid insecticide acetamiprid via the N-carbamoylimine derivate (IM-1-2) mediated by the nitrile hydratase of the nitrogen-fixing bacterium Ensifer meliloti CGMCC 7333.

    Science.gov (United States)

    Zhou, Ling-Yan; Zhang, Long-Jiang; Sun, Shi-Lei; Ge, Feng; Mao, Shi-Yun; Ma, Yuan; Liu, Zhong-Hua; Dai, Yi-Jun; Yuan, Sheng

    2014-10-15

    The metabolism of the widely used neonicotinoid insecticide acetamiprid (ACE) has been extensively studied in plants, animals, soils, and microbes. However, hydration of the N-cyanoimine group in ACE to the N-carbamoylimine derivate (IM-1-2) by purified microbes, the enzyme responsible for this biotransformation, and further degradation of IM-1-2 have not been studied. The present study used liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy to determine that the nitrogen-fixing bacterium Ensifer meliloti CGMCC 7333 transforms ACE to IM-1-2. CGMCC 7333 cells degraded 65.1% of ACE in 96 h, with a half-life of 2.6 days. Escherichia coli Rosetta (DE3) overexpressing the nitrile hydratase (NHase) from CGMCC 7333 and purified NHase converted ACE to IM-1-2 with degradation ratios of 97.1% in 100 min and 93.9% in 120 min, respectively. Interestingly, IM-1-2 was not further degraded by CGMCC 7333, whereas it was spontaneously hydrolyzed at the N-carbamoylimine group to the derivate ACE-NH, which was further converted to the derivative ACE-NH2. Then, ACE-NH2 was cleaved to the major metabolite IM-1-4. IM-1-2 showed significantly lower insecticidal activity than ACE against the aphid Aphis craccivora Koch. The present findings will improve the understanding of the environmental fate of ACE and the corresponding enzymatic mechanisms of degradation.

  4. Effect of Sodium Humate on Symbiotic Nitrogen - fixing and Photosynthetic Activity of Soybean%腐植酸钠对大豆共生固氮及光合作用的影响

    Institute of Scientific and Technical Information of China (English)

    吉利巴B.A.; 西涅果夫斯卡娅B.T.; 沃洛赫(N).Π.; 苏哈鲁科夫B.Π.

    2012-01-01

    Soybean was seed-coaled with Sodium humate,Rhizobia arid other fertilizers,and leaf sprayed with Sodium humate. Among the treatments,seed-coated with Sodium humate,Rhizobia(KB11 +MM117) ,Ammonium molybdate and leaf sprayed Sodium humate increased leaf area,photosynthetic potential, improved nodule number,weight and nitrogen-fixing efficiency, hence, got the highest seed yield of 2360 kg · ha-1, which was 22% higher than that of control.%以“和谐”号大豆为材料,研究了腐植酸钠与根瘤菌剂和不同肥料处理对大豆共生固氮和光合作用的影响.结果表明,利用腐植酸钠、钼酸铵、根瘤菌剂(KS11+ MM117)进行拌种和生育期间叶面喷施腐植酸钠处理,增加了叶面积和光合势,提高了根瘤数量、根瘤干物质积累量和固氮效率,最终获得的籽粒产量高达2360 kg·hm-2,较对照提高了22%.

  5. Spiruline, a virtuous algae

    OpenAIRE

    Various, Authors

    2015-01-01

    A short video about a local development practice focusing on the production and commercialization of spiruline, an algae used as an nutritional integrator. The practice was one of six prize winners resulting from a national competition for innovative practices of local development, launched by the Senegalese Ministry of local governance, development and territorial planning, with funding from the Italian Cooperation and technical support from the KIP International School.

  6. Light adaptation of the unicellular red alga, Cyanidioschyzon merolae, probed by time-resolved fluorescence spectroscopy.

    Science.gov (United States)

    Ueno, Yoshifumi; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

    2015-08-01

    Photosynthetic organisms change the quantity and/or quality of their pigment-protein complexes and the interactions among these complexes in response to light conditions. In the present study, we analyzed light adaptation of the unicellular red alga Cyanidioschyzon merolae, whose pigment composition is similar to that of cyanobacteria because its phycobilisomes (PBS) lack phycoerythrin. C. merolae were grown under different light qualities, and their responses were measured by steady-state absorption, steady-state fluorescence, and picosecond time-resolved fluorescence spectroscopies. Cells were cultivated under four monochromatic light-emitting diodes (blue, green, yellow, and red), and changes in pigment composition and energy transfer were observed. Cells grown under blue and green light increased their relative phycocyanin levels compared with cells cultured under white light. Energy-transfer processes to photosystem I (PSI) were sensitive to yellow and red light. The contribution of direct energy transfer from PBS to PSI increased only under yellow light, while red light induced a reduction in energy transfer from photosystem II to PSI and an increase in energy transfer from light-harvesting chlorophyll protein complex I to PSI. Differences in pigment composition, growth, and energy transfer under different light qualities are discussed.

  7. Biosorption of cadmium and lead from aqueous solution by fresh water alga Anabaena sphaerica biomass

    Directory of Open Access Journals (Sweden)

    Azza M. Abdel -Aty

    2013-07-01

    Full Text Available The present work represents the biosorption of Cd(II and Pb(II from aqueous solution onto the biomass of the blue green alga Anabaena sphaerica as a function of pH, biosorbent dosage, contact time, and initial metal ion concentrations. Freundlich, Langmuir, and Dubinin–Radushkevich (D–R models were applied to describe the biosorption isotherm of both metals by A. sphaerica biomass. The biosorption isotherms studies indicated that the biosorption of Cd(II and Pb(II follows the Langmuir and Freundlish models. The maximum biosorption capacities (qmax were 111.1 and 121.95 mg/g, respectively, at the optimum conditions for each metal. From the D–R isotherm model, the mean free energy was calculated to be 11.7 and 14.3 kJ/mol indicating that the biosorption mechanism of Cd(II and Pb(II by A. sphaerica was chemisorption. The FTIR analysis for surface function group of algal biomass revealed the existence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for the biosorption of Cd(II and Pb(II. The results suggested that the biomass of A. sphaerica is an extremely efficient biosorbent for the removal of Cd(II and Pb(II from aqueous solutions.

  8. Effects of Location Fertilization Managements on the Nitrogen-fixing Bacteria Diversities of Soybean in Dong-bei black soil%定位培肥对东北黑土土壤固氮菌多样性的影响

    Institute of Scientific and Technical Information of China (English)

    王大庆; 刘朴方; 孙泰朋; 孟雨田; 赵伟; 王宏燕

    2016-01-01

    基于10年的黑土培肥定位试验,本试验采用PCR-DGGE、克隆测序技术的方法,研究了培肥处理对大豆固氮菌多样性的影响。 DGGE 图谱分析表明对照土壤固氮菌多样性指数最高,其次为农肥低量处理、农化1:1处理、化肥低量处理和农肥高量处理,化肥高量处理土壤固氮菌多样性指数最低。在相似度60%水平上化肥处理聚成一群,对照、农肥处理和农化1:1处理量聚成一群。培肥处理降低了土壤固氮菌的多样性,影响了土壤中固氮菌的群落结构,其中培肥高量处理比低量处理降低土壤固氮菌多样性的效果更显著。%Through a 10-year experiment site on black soil, our paper studied the effects of location fertilization managements on the nitrogen-fixing bacteria diversities of soybean in Dong-bei black soil by PCR-DGGE and clone sequencing methods. DGGE atlas analysis demonstrated that nitrogen-fixing bacteria diversities of CK was the highest and the lowest nitrogen-fixing bacteria diversities was high chemical fertilizer treatment and then was low manure fertilizer, 1/2 manure fertilizer plus 1/2 chemical fertilizer, low chemical fertilizer, and high manure fertilizer. There were two groups in similarity 60% level, one was chemical fertilizer, the other was CK, manure fertilizer, and 1/2 manure fertilizer plus 1/2 chemical fertilizer. Fertilizer managements reduced nitrogen-fixing bacteria diversities of soybean and influenced community structures of nitrogen-fixing bacteria, especially high fertilizer managements could decrease nitrogen-fixing bacteria diversities of soybean more notablly than low fertilizer managements.

  9. Stress tolerant crops from nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R.; Saunders, R.M.

    1983-01-01

    Notes are given on the nutritional quality and uses of: pods of Geoffroea decorticans, a species tolerant of saline and limed soils and saline water; seeds of Olneya tesota which nodulates readily and fixes nitrogen and photosynthesizes at low water potential; and pods of Prosopis chilensis and P. tamarugo which tolerate long periods without rain. 3 references.

  10. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in common that

  11. Nitrogen-fixing methane-utilizing bacteria

    NARCIS (Netherlands)

    Bont, de J.A.M.

    1976-01-01

    Methane occurs abundantly in nature. In the presence of oxygen this gas may be metabolized by bacteria that are able to use it as carbon and energy source. Several types of bacteria involved in the oxidation of methane have been described in literature. Methane-utilizing bacteria have in

  12. Diversity of associated nitrogen-fixing bacteria isolated from the pioneer plants-Vetiver zizanioides%先锋牧草-香根草联合固氮菌多样性

    Institute of Scientific and Technical Information of China (English)

    赵现伟; Chaudhary Hassan Javed; 何玉梅; 张志英; 彭桂香; 谭志远

    2009-01-01

    [目的]香根草(Vetiver zizanioides)是一种多年生禾本科草本植物,具有极强的生态适应性和抗逆能力,可作饲料和水土保持用.通过研究香根草联合固氮菌多样性,为进一步研究和应用打下基础.[方法]采用无氮培养基,首次从香根草中分离到47株联合固氮菌,分别应用SDS-PAGE全细胞蛋白质电泳、DNA指纹图谱、唯一碳源和16S rDNA全序列测定等方法,进行聚类和多样性分析.[结果]SDS-PAGE、IS-PCR和Bio-BIQA碳源利用的聚类结果基本一致,将供试菌株分为6个类群和4个单菌株;16S rDNA序列测定表明,从香根草中分离的菌株包括了佛莱辛草螺菌(Herbaspirillum frisingense)、中型假食酸菌(Pseudacidovorax intermedius)、恶臭假单胞菌(Pseudomonas putida)、荧光假单胞菌(Pseudomonas fluorescens)、越南伯克氏菌(Burkholderia vietnamiensis)、阴沟肠杆菌(Enterobacter cloacae)、路德维希肠杆菌(Enterobacter ludwigii)和松江壳聚糖降解菌(Mitsuaria chitosanitabida)等不同菌种.[结论]香根草联合固氮菌具有较大的资源多样性,对固氮菌资源的扩展和将来牧草上的应用具有重要意义.%[Objective] Vetiver zizanioides is a perennial grass of the Poaceae family, known of its silage, soil and water conservation role. The aim of the study was to collect and identify the resources of the nitrogen-fixing bacteria associated with Vetiver zizanioides. [Methods] Associated nitrogen-fixing bacteria isolated from Vetiver zizanioides were studied by SDS-PAGE whole-cell protein patterns, insert sequence (IS)-PCR finger printing, utilization of sole carbon sources and 16S rRNA gene sequence analysis. [Results] Based on the results of finger printing analysis, protein patterns and biological test, isolates were grouped into 6 clusters, except 4 single strains. Phylogenetic analysis of 16S rDNA sequences indicated that isolates belonged to Herbaspirillum frisingense,Enterobacter ludwigii

  13. Space-Based Blue-Green Laser.

    Science.gov (United States)

    1981-10-01

    E- BEAM //:. O 2.2 A/cm 0 X60 - Cf) 40- 0 0 0 0 I.Ac 2 00 1. 1 A/cm z ": 20- 0.55/cm 2 0L I I I I "" 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4. S J8838 E/N (10...discharge coefficient through orifices in the perforated plate; Api /pc is the incident pressure wave strength and 7 is the ratio of gas specific heats...pulse overpressure, .. - Api /pc = 0.064, Eq. (17) provides the specification of effec- tive upstream muffler transparency aCD= 0.086. The upstream

  14. Blue-Green Laser Diode Research Program.

    Science.gov (United States)

    1986-10-01

    molecular beam epitaxy", J. Materials Research, 1, 543 (1986). 11. H.E. Ruda , "The Application of Free Carrier Absorption to N-ZnSe Materials...Characterization", submuitted to j. Appi. Phys. 12. H.E. Ruda , J. Appl. Phys. 59, 1220 (1986). 13. H.E. Ruda , J. Appl. Phys. 59, 3516 (1986). 14. R.K. Swank, M. Avan, and J.Z. Devine, J. Appl. Phys. 40, 89 (1969). 55 -Y ~’c.

  15. ECOLOGICAL FEATURES OF ALGAE COMMUNITIES IN FOREST FLOOR OF PINE PLANTATIONS OF DIFFERENT TYPES OF LANDSCAPES IN STEPPE AREA OF UKRAINE

    Directory of Open Access Journals (Sweden)

    Maltsev Yevhen

    2013-12-01

    Full Text Available The steppe zone of Ukraine features a large variety of types of natural landscapes that together significantly differ in microclimatic, soil, hydrological and geobotanic conditions. Such a diversity of forest conditions affects not only the trees, but also on all biotic components of forest ecosystems including algae. Purpose of the study was establish systematic position of species, dominant and subdominant, leading families of algae for plantings in forest floor of pine plantations of the valley-terrace and inundable-terrace landscapes in steppe area of Ukraine. In general, in the forest floor of Samara pine forest marked 34 species of algae with 4 divisions, most of which related to green: Chlorophyta – 22 (65%, Xanthophyta – 8 (23%, Bacillariophyta – 2 (6% and Eustigmatophyta – 2 (6%. Among the leading families of the greatest number of species belonged to: Pleurochloridaceae (7 species, Chlorococcaceae (5, Chlamydomonadaceae (4. During all studied seasons in base of algae communities were species resistant to extreme values of all climatic conditions. Total in forest floor of pine forest in Altagir forest marked 42 species of algae with 5 divisions: Chlorophyta - 23 (55 %, Xanthophyta - 9 (21 %, Cyanophyta - 5 (12 %, Bacillariophyta - 3 (7% and Eustigmatophyta – 2 (5%. Systematic structure of list species determine three family, which have the number of species in excess of the average number (2: Pleurochloridaceae, Chlamydomonadaceae and Myrmeciaceae. The base of algae community are moisture-loving and shade-tolerant species, which may be the result of favorable moisture regime. In the forest floor of pine plantings in forest floor of pine plantations of the valley-terrace (Samara pine forest and inundable-terrace (Altagir forest landscapes found 64 species of algae with 5 divisions, which are dominated by green algae - 37 species (58%, that exceed xanthophytes - 15 (23%, blue-green 5 (8 %, eustigmatofites 4 (6% and diatoms 3 (5

  16. Isolation and identification of associative nitrogen-fixing bacteria in the rhizosphere of Axonopus compressus%地毯草根际固氮菌的分离及鉴定

    Institute of Scientific and Technical Information of China (English)

    樊俊华; 张晓波; 赵艳

    2012-01-01

    This study isolates and identifies associative nitrogen-fixing bacteria from the rhizo-sphere of Axonopus compressus by acetylene reduction assay (ARA) combined with gas chroma-tography(GC). Six strains were isolated, and showed that nitrogenase activity was large variation between strains (from 92.5 C2H4 to 295.2 C2H4 nmol·mL-1·h-1). Strains hnN2 and hnN6 showed higher nitrogenase activity (>200 C2H4 nmol·mL-1·h-'). All strains belonged to Bacillus(2 strains), Azotobacter (3 strains) and Pseudomonas (1 strains), respectively.%结合气相色谱仪,利用乙炔还原等方法对地毯草(Axonopus compressus)根际固氮菌进行分离和鉴定.结果表明,从地毯草根际土壤中分离获得6株固氮菌株,菌株的固氮酶活性相差较大(92.5 C2H4~295.2 C2H4nmol·mL-1·h-1),菌株hnN2及hnN6具有较高的固氮酶活性(>200 C2H4nmol·mL-1·h-1);菌株经鉴定分属Bacillus(2株)、Azotobacter(3株)和Pseudomonas(1株)3个属.

  17. Miocene Coralline algae

    Energy Technology Data Exchange (ETDEWEB)

    Bosence, D.W.J.

    1988-01-01

    The coralline algae (Order Corallinales) were sedimentologically and ecologically important during the Miocene, a period when they were particularly abundant. The many poorly described and illustrated species and the lack of quantitative data in coralline thalli make specific determinations particularly difficult, but some species are well known and widespread in the Tethyan area. The sedimentologic importance of the Miocene coralline algae is reflected in the abundance of in-situ coralline buildups, rhodoliths, and coralline debris facies at Malta and Spain; similar sequences are known throughout the Tethyan Miocene. In-situ buildups vary from leafy crustose biostromes to walled reefs with dense coralline crusts and branches. Growth forms are apparently related to hydraulic energy. Rhodoliths vary from leafy, crustose, and open-branched forms in muddy sediments to dense, crustose, and radial-branching forms in coarse grainstones. Rhodolith form and internal structure correlate closely with hydraulic energy. Coralline genera are conservative and, as such, are useful in paleoenvironmental analysis. Of particular interest are the restricted depth ranges of recent coralline genera. More research is needed on the sedimentology, paleoecology, and systematics of the Cenozoic corallines, as they have particular value in paleoenvironmental analysis.

  18. "Logistic analysis of algae cultivation"

    NARCIS (Netherlands)

    Slegers, P.M.; Leduc, S.; Wijffels, R.H.; Straten, van G.; Boxtel, van A.J.B.

    2015-01-01

    Energy requirements for resource transport of algae cultivation are unknown. This work describes the quantitative analysis of energy requirements for water and CO2 transport. Algae cultivation models were combined with the quantitative logistic decision model ‘BeWhere’ for the regions Benelux

  19. Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp:Phosphorus dynamics

    Institute of Scientific and Technical Information of China (English)

    Suiliang Huang; Baoyan Liu; Shaoming Wang; Yang Luo; Adam Szymkiewicz; Romuald Szymkiewicz; Min Wu; Changjuan Zang; Shenglan Du; Joseph Domagalski; Magdalena Gajewska; Feng Gao; Chao Lin; Yong Guo

    2016-01-01

    This is the third paper of the series about “Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp”. In this paper, phosphorus dynamics were inves-tigated under the condition of culturing bighead carp and common carp with added fish food (nitrogen dynamics is discussed in the second paper because their behaviors are so different from each other). Nearly fifty days’ observation results indicated that the reservoir water was typical of “phosphorus limited” water, and soluble reactive phosphorus (SRP) was the main constituent of measured total phosphorus (TP). The presence of fish food resulted in significantly higher SRP, dissolved total phos-phorus (DTP) and TP concentrations in contrast with the reservoir water. Moreover, continuous supply of fish food led to the decline of total nitrogen to total phosphorus (TN:TP) from more than 100 to less than 5. Variations in the ratio of TN to TP favored the growth of blue-green algae. Fish species affected phosphorus concentrations, and culturing bait-eating common carp contributed more to reducing the SRP, DTP and TP concentrations than culturing planktivorous bighead carp. 0.5%, 4.1%and 3.1%TP can be removed in enclosures with culturing bighead carp, common carp and mixed bighead carp and common carp, respectively. Abundant phosphorus in the fish culturing activities may be present as the uneaten food, algae cells, and within the water column and sediment, which should be taken into serious con-sideration for the target of future water eutrophication prevention and safety of the drinking water supply.

  20. Gulf ring algae

    Science.gov (United States)

    Although they rank among the tiniest of the microspcopic phytoplankton, coccolithophore algae aid oceanographers studying the Gulf Stream rings and the ring boundaries. The algal group could help to identify more precisely the boundary of the warm rings of water that spin off from the Gulf Stream and become independent pools of warm water in the colder waters along the northeastern U.S. coast.Coccolithophore populations in the Gulf Stream rings intrigue oceanographers for two reasons: The phytoplankton are subjected to an environment that changes every few days, and population explosions within one coccolithophore species seem to be associated with changes in the characteristics of ocean water, said Pat Blackwelder, an associate professor at the Nova Oceanographic Center in Dania, Fla. She is one of many studying the physics, chemistry, and biology of warm core rings. A special oceanography session on these rings was held at the recent AGU Fall Meeting/ASLO Winter Meeting.

  1. 隐藻藻胆蛋白的结构与能量传递功能%The Structure and Energy Transfer of Phycobiliproteins in Cryptophytic Algae

    Institute of Scientific and Technical Information of China (English)

    陈敏; 王宁; 杨多利; 李文军

    2015-01-01

    藻胆蛋白主要存在于蓝藻、红藻及部分隐藻,作为主要的捕光复合物担负着吸收和传递光能的作用。同时藻胆蛋白还是具有很高量子产率的荧光蛋白,因而在光合理论研究及应用方面受到广泛的关注。隐藻藻胆蛋白继承自红藻,但在其蛋白和色基结构、组成、性质、在叶绿体中的存在状态以及与光合膜上反应中心的接触方式等方面都与红、蓝藻藻胆蛋白不同。目前对于红、蓝藻中的藻胆蛋白以及组装而成的藻胆体等均有相当透彻的研究,而对于隐藻藻胆蛋白的了解要少得多。隐藻藻胆蛋白在进化上可能属于比较原始的类型,并且结构上相对于庞大的藻胆体简单得多,因此对于了解藻胆蛋白基本的结构与捕光功能的关系、探讨隐藻的进化地位以及光合生物进化的亲缘关系等的研究方面,具有重要意义,也更为便捷。本文从结构和能量传递功能等方面对目前发现的隐藻藻胆蛋白的研究近况做了综述,总结了目前研究存在的不明之处,并对今后的研究思路提出了看法。%Phycobiliproteins are mainly found in blue-green algae, red algae and some species of cryptophytic algae. They function as major light-harvesting complexes to harvest and transfer sunlight energy. Meanwhile, phycobiliproteins are also lfuorescent proteins with high lfuorescence quantum yield, and in consequence be widely concerned in both theoretical photosynthesis investigation and application. The cryptophytic phycobilip-roteins are inherited from red algae but varied in several ways compared to phycobiliproteins from red algae and blue-green algae, including their protein and phycobilin structure, composition, properties, existential states within chloroplast, as well as the contact forms with reaction centers embedded in photosynthetic membrane, etc. At present, there is a thorough understanding with both phycobiliproteins and

  2. Fuel From Algae: Scaling and Commercialization of Algae Harvesting Technologies

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-01-15

    Broad Funding Opportunity Announcement Project: Led by CEO Ross Youngs, AVS has patented a cost-effective dewatering technology that separates micro-solids (algae) from water. Separating micro-solids from water traditionally requires a centrifuge, which uses significant energy to spin the water mass and force materials of different densities to separate from one another. In a comparative analysis, dewatering 1 ton of algae in a centrifuge costs around $3,400. AVS’s Solid-Liquid Separation (SLS) system is less energy-intensive and less expensive, costing $1.92 to process 1 ton of algae. The SLS technology uses capillary dewatering with filter media to gently facilitate water separation, leaving behind dewatered algae which can then be used as a source for biofuels and bio-products. The biomimicry of the SLS technology emulates the way plants absorb and spread water to their capillaries.

  3. Neuroprotective effects of marine algae.

    Science.gov (United States)

    Pangestuti, Ratih; Kim, Se-Kwon

    2011-01-01

    The marine environment is known as a rich source of chemical structures with numerous beneficial health effects. Among marine organisms, marine algae have been identified as an under-exploited plant resource, although they have long been recognized as valuable sources of structurally diverse bioactive compounds. Presently, several lines of studies have provided insight into biological activities and neuroprotective effects of marine algae including antioxidant, anti-neuroinflammatory, cholinesterase inhibitory activity and the inhibition of neuronal death. Hence, marine algae have great potential to be used for neuroprotection as part of pharmaceuticals, nutraceuticals and functional foods. This contribution presents an overview of marine algal neuroprotective effects and their potential application in neuroprotection.

  4. Desempenho do arroz irrigado em resposta à utilização de cianobactérias fixadoras de nitrogênio = Performance of paddy rice in response to the use of nitrogen-fixing cyanobacteria

    Directory of Open Access Journals (Sweden)

    Edgardo Oscar Brenzoni

    2007-01-01

    Full Text Available O objetivo do presente estudo foi avaliar a utilização de inóculos decianobactérias fixadoras de nitrogênio como alternativa à adubação química de nitrogênio na cultura do arroz irrigado. Para tanto, foram conduzidos quatro experimentos, nos anos agrícolas de 1999/00 a 2002/03, avaliando os tratamentos: testemunha sem aplicação de N em cobertura; 20 kg ha-1 de N aplicado em cobertura; 40 kg ha-1 de N aplicado em cobertura; 90 kg ha-1 de N aplicado em cobertura; 50 g ha-1 de Rizogram®; 100 g ha-1 de Rizogram®. Verificou-se interação dos tratamentos com os anos avaliados, o que pode ter ocultado o desempenho destes. Além disso, verificou-se que, para a variável “número de grãos por panícula”, a utilização de cianobactérias nas duas dosagens estudadas (50 e 100 g ha-1 produziu resultados semelhantes à adubação nitrogenada (90 kg ha-1, com potencialredução do número porcentual de espiguetas estéreis. Os tratamentos não afetaram o rendimento de grãos do arroz irrigado, devido às variações ambientais dos anos avaliados.A four-year experiment irrigated rice was carried out in order to evaluate the performance of Nostoc sp. and Tolypothrix sp. nitrogen-fixing cyanobacteria strains (Rizogram™, as an alternative to chemical nitrogen fertilization in irrigated rice. The treatments evaluated in the experiments included: control without top dressing Napplication; top dressing application of 20, 40 and 90 kg ha-1; 50 g ha-1 of Rizogram™, and 100 g ha-1 of Rizogram™. It was verified interaction between the years of the study and the treatments, which may have affected the performance of these treatments. Moreover, it was observed that, for the number of grains per panicle, the use of cyanobacteria in two studied rates (50 e 100 g ha-1 produced the same results as the nitrogen fertilization (90 kg ha-1, showing potential reduction of sterile spikelets. However, the treatments did not affected rice grain yield.

  5. 结缕草根际联合固氮菌的分离及初步鉴定%Isolation and identification of associative nitrogen-fixing bacteria in the rhizosphere of Zoysia japonica

    Institute of Scientific and Technical Information of China (English)

    张晓波; 赵艳

    2011-01-01

    联合固氮菌在植物根际土壤生长或定植于植物根表细胞,这类细菌可将空气或土壤中的氮素转化为氨态氮供植物直接吸收利用.结合气相色谱仪,利用乙炔还原等方法对结缕草根际联合固氮菌进行了分离和鉴定.结果表明:从结缕草根际土壤中分离获得9株联合固氮菌株,菌株的固氮酶活性相差较大,为67.5~343.7 C2H4nmol/(ml·h),菌株N4及N6具有较高的固氮酶活性,>300 C2 H4nmol/(mL·h);除N4外其余菌株均为革兰氏阴性菌,菌株经鉴定分属Bacillus(1株)、Enterobacter(1株)、Azotobacter(4株)和Pseudomonas(3株)4个属.%Associative nitrogen-fixing bacteria(ANB)from the rhizosphere of Zoysia japonica were isolated and identified by acetylene reduction assay(ARA)combined with gas chromatography(GC). Nine ANB strains were isolated,and their nitrogenase activity were variation between strains(from 67. 5 C2 H4 nmol/mL · h to 343.7 C2 H4 nmol/mL · h). Strains N4 and N6 showed higher nitrogenase activity (>300 C2 H4 nmol/mL · h). In addition,all strains obtained were gram-negative except N4,and belonged to Bacillus(1 strains),Enterobacter (1 strains) ,Azotobacter(4 strains) and Pseudomonas(3 strains), respectively.

  6. Aislamientos de cepas fijadoras de nitrógeno y solubilizadoras de fósforo en un suelo alfisol venezolano Isolation of nitrogen-fixing and phosporus-solubilizing strains in alfisol soils of Venezuela

    Directory of Open Access Journals (Sweden)

    Learsy Padron

    2012-04-01

    Full Text Available Para evaluar el potencial de los suelos del Valle Medio del Río Yaracuy para la producción de biofertilizantes, se aislaron cepas fijadoras de nitrógeno (FNVL y solubilizadoras de fósforo (SF en suelos sometidos a diferentes condiciones de manejos. Para ello muestra rizosferica en los usos caña de azúcar (Sacharum oficcinarum, maíz (Zea mayz L., lechoza (Carica papaya, pasto (Brachiaria decumbens, además de un área bajo bosque natural, las muestras fueron tomadas en abril de 2010, las bacterias FNVL y SF fueron aisladas usando medio Ashby y Pikoskaya respectivamente, las principales propiedades químicas y físicas del suelo fueron evaluadas, para establecer su relación con el desarrollo de las cepas. Los resultados muestran que las FN se desarrollaron mejor en los usos pasto y caña de azúcar con 20 y 10 cepas respectivamente, lo que indica que las cepas FNVL se desarrollaron mejor en aquellos manejos con bajo contenido de materia orgánica o manejo intensivo, el mayor numero de bacterias SF se observaron en aquellos manejos con mayor contenido de fósforo (lechoza con 13 colonias, o en usos con adecuadas condiciones físicas para el desarrollo microorganismos (bosque, con 10 colonias.In order to evaluate the potential of soils in the Middle Valley of Yaracuy River in Venezuela for the production of biofertilizers, nitrogen fixed strains (FBN and phosphorus-solubilizing strains (SF were isolated in soils subjected to different management conditions. For this, rizhosferic samples in six different land uses were taken in April, 2010. Sugarcane (Sacharum officinarum, maize (Zea mayz L., pawpaw (Carica papaya, grass (Brachiaria decumbens and a forest area were sampled. Bacteria FNVL and SF were isolated using Ashby and Pikoskaya, respectively. Chemical and physical properties were evaluated in all soils to determine the relationship between them and the development of the strains. Results showed that Fn developed better in grass and

  7. Transgenic algae engineered for higher performance

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, Pat J; Anderson, Penelope S; Knight, Thomas J

    2014-10-21

    The present disclosure relates to transgenic algae having increased growth characteristics, and methods of increasing growth characteristics of algae. In particular, the disclosure relates to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and to transgenic algae comprising a glutamine phenylpyruvate transaminase transgene and a glutamine synthetase.

  8. Extraction, purification and nanoformulation of natural phycocyanin (from Klamath algae) for dermal and deeper soft tissue delivery.

    Science.gov (United States)

    Caddeo, Carla; Chessa, Maura; Vassallo, Antonio; Pons, Ramon; Diez-Sales, Octavio; Fadda, Anna Maria; Manconi, Maria

    2013-11-01

    This study focuses on the extraction and isolation of a natural anti-inflammatory phycocyanin and its nanoformulation in innovative and efficient vesicular carriers able to improve its delivery to the skin. C-phycocyanin was successfully isolated from a commercial dry extract (AfaMax) of blue-green Klamath algae. Protein extraction and purity were confirmed by gel electrophoresis (SDS PAGE), MALDI top-down sequencing, Liquid Chromatography/Mass Spectrometry, and UV absorption. Purified C-phycocyanin was then encapsulated in different phospholipid vesicles: liposomes, ethosomes and Penetration Enhancer containing Vesicles (PEVs), the latter containing the penetration enhancer propylene glycol or Transcutol P. The main colloidal characteristics of the systems were assessed, showing spherical vesicles around 100 nm, negatively charged, with different lamellarity depending on the formulation composition. An in depth investigation on vesicle geometrical properties and morphology was carried out by Small and Wide-Angle X-ray Scattering. Further, the ability of rhodamine-labelled vesicles to allow fluorescent phycocyanin penetration and distribution through human skin was evaluated by Confocal Laser Scanning Microscopy, while a complete picture of vesicle-treated skin architecture was gained using Scanning Electron Microscopy. Results indicate that PEVs, especially propylene glycol containing vesicles, are promising carriers for the delivery of the high molecular weight protein phycocyanin to the deep skin layers.

  9. Optimization of mechanical stirring technology in anaerobic fermentation treating algae and pilot trial validation%蓝藻厌氧发酵产沼气机械搅拌工艺优化及中试验证

    Institute of Scientific and Technical Information of China (English)

    余亚琴; 吴义锋

    2014-01-01

    Water pollution caused by the excessive growth of blue-green algae has become a growing environmental problem. One current approach to reducing the algae in Taihu Lake is to refloat the algae after a bloom has occurred. It can remove nitrogen and phosphorus in the lake simultaneously. The amount of algae-laden water collected from Taihu Lake can be up to approximately several thousand tons in wet weight per day. And they needs timely and effective treatment. The algae can be effectively degraded and produced into methane by anaerobic fermentation technology. The algae is easy to float and crust in the reactor, thus affecting the efficiency of the gas production and reducing the processing effect of the reactor. In anaerobic reactors, proper stirring can prevent algae floating and facilitate contact between the algae and other microbes, thereby improving gas production efficiency. This paper designed experimental device for optimizing the stirring of blue-green algae anaerobic fermentation. The device was made of double transparent glass with a working volume of 3 L. The device was equipped with an adjustable speed motor, which control the stirring interval, stirring duration and stirring cycle. Response surface methodology (RSM) was employed to optimize the stirring conditions. Simultaneously, the pilot study was adopted to provide a support of the best stirring condition of blue-green algae anaerobic fermentation. In the pilot study, protease content was assayed to characterize hydrolysis activity, TTC-dehydrogenase content was measured to characterize microbial enzyme activity, and coenzyme F420 content showed the activity of methanogenic anaerobes. The experimental results showed that the algae anaerobic fermentation was influenced by stirring interval, stirring duration, and stirring cycle. The correlation coefficient of the RSM regression equation was 0.98. RSM revealed the optimized stirring parameters for algae anaerobic fermentation as follows

  10. Neuroprotective Effects of Marine Algae

    Directory of Open Access Journals (Sweden)

    Se-Kwon Kim

    2011-05-01

    Full Text Available The marine environment is known as a rich source of chemical structures with numerous beneficial health effects. Among marine organisms, marine algae have been identified as an under-exploited plant resource, although they have long been recognized as valuable sources of structurally diverse bioactive compounds. Presently, several lines of studies have provided insight into biological activities and neuroprotective effects of marine algae including antioxidant, anti-neuroinflammatory, cholinesterase inhibitory activity and the inhibition of neuronal death. Hence, marine algae have great potential to be used for neuroprotection as part of pharmaceuticals, nutraceuticals and functional foods. This contribution presents an overview of marine algal neuroprotective effects and their potential application in neuroprotection.

  11. Polysaccharides of the red algae.

    Science.gov (United States)

    Usov, Anatolii I

    2011-01-01

    Red algae (Rhodophyta) are known as the source of unique sulfated galactans, such as agar, agarose, and carrageenans. The wide practical uses of these polysaccharides are based on their ability to form strong gels in aqueous solutions. Gelling polysaccharides usually have molecules built up of repeating disaccharide units with a regular distribution of sulfate groups, but most of the red algal species contain more complex galactans devoid of gelling ability because of various deviations from the regular structure. Moreover, several red algae may contain sulfated mannans or neutral xylans instead of sulfated galactans as the main structural polysaccharides. This chapter is devoted to a description of the structural diversity of polysaccharides found in the red algae, with special emphasis on the methods of structural analysis of sulfated galactans. In addition to the structural information, some data on the possible use of red algal polysaccharides as biologically active polymers or as taxonomic markers are briefly discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Algae Bloom in a Lake

    Directory of Open Access Journals (Sweden)

    David Sanabria

    2008-01-01

    Full Text Available The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface of this lake within a specified time and under specified conditions.

  13. Cyanobacteria: algas productoras de toxinas

    OpenAIRE

    Echenique, Ricardo Omar; Giannuzzi, Leda; Andrinolo, Darío

    2007-01-01

    El de las Cyanobacteria es un grupo de algas con características particulares. Por su coloración, dada por los pigmentos que posee, comúnmente se las conoce como algas verde-azules. Según registros fósiles, son los primeros organismos fotosintéticos aparecidos en nuestro planeta (3000-3500 millones de años), por esto se los consideran los responsables de originar la atmósfera inicial que posibilitó la evolución del resto de los seres vivos habitantes de la Tierra. Estos organismos, desde micr...

  14. Mercury analysis of acid- and alkaline-reduced biological samples: identification of meta-cinnabar as the major biotransformed compound in algae.

    Science.gov (United States)

    Kelly, David; Budd, Kenneth; Lefebvre, Daniel D

    2006-01-01

    The biotransformation of Hg(II) in pH-controlled and aerated algal cultures was investigated. Previous researchers have observed losses in Hg detection in vitro with the addition of cysteine under acid reduction conditions in the presence of SnCl2. They proposed that this was the effect of Hg-thiol complexing. The present study found that cysteine-Hg, protein and nonprotein thiol chelates, and nucleoside chelates of Hg were all fully detectable under acid reduction conditions without previous digestion. Furthermore, organic (R-Hg) mercury compounds could not be detected under either the acid or alkaline reduction conditions, and only beta-HgS was detected under alkaline and not under acid SnCl2 reduction conditions. The blue-green alga Limnothrix planctonica biotransformed the bulk of Hg(II) applied as HgCl2 into a form with the analytical properties of beta-HgS. Similar results were obtained for the eukaryotic alga Selenastrum minutum. No evidence for the synthesis of organomercurials such as CH3Hg+ was obtained from analysis of either airstream or biomass samples under the aerobic conditions of the study. An analytical procedure that involved both acid and alkaline reduction was developed. It provides the first selective method for the determination of beta-HgS in biological samples. Under aerobic conditions, Hg(II) is biotransformed mainly into beta-HgS (meta-cinnabar), and this occurs in both prokaryotic and eukaryotic algae. This has important implications with respect to identification of mercury species and cycling in aquatic habitats.

  15. Formation of algae growth constitutive relations for improved algae modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Gharagozloo, Patricia E.; Drewry, Jessica Louise.

    2013-01-01

    This SAND report summarizes research conducted as a part of a two year Laboratory Directed Research and Development (LDRD) project to improve our abilities to model algal cultivation. Algae-based biofuels have generated much excitement due to their potentially large oil yield from relatively small land use and without interfering with the food or water supply. Algae mitigate atmospheric CO2 through metabolism. Efficient production of algal biofuels could reduce dependence on foreign oil by providing a domestic renewable energy source. Important factors controlling algal productivity include temperature, nutrient concentrations, salinity, pH, and the light-to-biomass conversion rate. Computational models allow for inexpensive predictions of algae growth kinetics in these non-ideal conditions for various bioreactor sizes and geometries without the need for multiple expensive measurement setups. However, these models need to be calibrated for each algal strain. In this work, we conduct a parametric study of key marine algae strains and apply the findings to a computational model.

  16. Studies on the Removing Efficiency of Algae by A New Disinfect Agent%一种新型消毒剂的杀藻研究

    Institute of Scientific and Technical Information of China (English)

    况琪军; 夏宜罫; 吴紫元

    2001-01-01

    The removing efficiency on algae (4 algae species in 3 phyla)by adisinfect agent contained Ca(ClO)2 was studied.The removing rates on Scenedesmus dimorphus,Microsystis flos-aquae,Synedra acus and Cyclotella meneghiniana are 100.0%,52.1%,60.5% and 73.3% when the algae exposed in the disinfect agent with 62.5ppm available chlorine for 48h,respectively.When the blue-green algae and diatoms exposed to 62.5ppm available chlorine for 96h,they died wholly.At a high concentration of available chlorine (500ppm),4 species of algae were died completely only in a few minutes.No obvious harm to algae was found at the concentration of ≤1ppm available chlorine.%由藻类过量繁殖引发的富营养化所造成的危害越来越严重并日益受到关注。采用钠法工艺生产的次氯酸钙是一种无残毒、不产生二次污染的高效广谱灭菌药物。对该药物的杀藻效率进行生物测试的结果表明,它能有效地杀灭引发水华的绿藻、蓝藻和硅藻。≥62.5ppm(有效氯含量,下同)曝露96h,4种被试藻类的死亡率可达92%~100%。高浓度(500ppm)条件下,绿藻、蓝藻和硅藻分别在几分钟和1h内全部死亡。≤1ppm的浓度对4种被试藻类基本上不造成严重伤害。

  17. 21 CFR 184.1120 - Brown algae.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1120 Brown algae. (a) Brown algae are seaweeds of the species Analipus...

  18. Scenario studies for algae production

    NARCIS (Netherlands)

    Slegers, P.M.

    2014-01-01

    Microalgae are a promising biomass for the biobased economy to produce food, feed, fuel, chemicals and materials. So far, large-scale production of algae is limited and as a result estimates on the performance of such large systems are scarce. There is a need to estimate large-scale biomass producti

  19. Scenario studies for algae production

    NARCIS (Netherlands)

    Slegers, P.M.

    2014-01-01

    Microalgae are a promising biomass for the biobased economy to produce food, feed, fuel, chemicals and materials. So far, large-scale production of algae is limited and as a result estimates on the performance of such large systems are scarce. There is a need to estimate large-scale biomass producti

  20. Macro algae as substrate for biogas production

    DEFF Research Database (Denmark)

    Møller, Henrik; Sarker, Shiplu; Gautam, Dhan Prasad

    Algae as a substrate for biogas is superior to other crops since it has a much higher yield of biomass per unit area and since algae grows in the seawater there will be no competition with food production on agricultural lands. So far, the progress in treating different groups of algae as a source...... of energy is promising. In this study 5 different algae types were tested for biogas potential and two algae were subsequent used for co-digestion with manure. Green seaweed, Ulva lactuca and brown seaweed Laminaria digitata was co-digested with cattle manure at mesophilic and thermophilic condition...

  1. Allelopatrhic effect of Acorus tatarinowii upon algae

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Besides competing with algae for light and mineralnutrients (i.e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in "A. tatarinowii water", some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTC) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A.tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 /disc, the inhibitory rate was negative; if it was over 45 /disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 /disc and 45 u?disc.

  2. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state Caracterização molecular de bactérias fixadoras de nitrogênio isoladas de plantas brasileiras no estado de São Paulo

    Directory of Open Access Journals (Sweden)

    Érica. L. Reinhardt

    2008-09-01

    Full Text Available Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data.Quatorze linhagens de bactérias fixadoras de nitrogênio foram isoladas de diferentes espécies de plantas, incluindo cassava, milho e cana-de-açúcar, usando condições seletivas desprovidas de nitrogênio. A capacidade de fixar nitrogênio foi verificada por ensaio de redução de acetileno. Todas as linhagens fixadoras de nitrogênio testadas apresentaram hibridização positiva com sonda de gene nifH derivada de Azospirillum brasilense. As linhagens foram caracterizadas por RAPD, ARDRA e sequenciamento do gene 16S rDNA. As análises de RAPD revelaram 8 genótipos, as 6 linhagens restantes foram agrupadas em 3 grupos de RAPD, sugerindo uma origem clonal. ARDRA e seqüências de 16S rDNA foram alocadas em 13 grupos conhecidos de bactérias fixadoras de nitrogênio, incluindo organismos dos gêneros Azospirillum, Herbaspirillum, Pseudomonas e Enterobacteriaceae. Duas linhagens foram classificadas como Stenotrophomonas ssp. Os resultados da identifica

  3. Influence of the Systemic Application of Blue–Green Spirulina platensis Algae on the Cutaneous Carotenoids and Elastic Fibers in Vivo

    Directory of Open Access Journals (Sweden)

    Maxim E. Darvin

    2015-09-01

    Full Text Available The objective of the study was to investigate the influence of a food supplement rich in antioxidants on the antioxidant status of the skin. For this reason, the blue-green algae Spirulina platensis powder was used for oral application during eight weeks. The effect of oral application of the antioxidant-containing Spirulina platensis on characteristic skin aging parameters, e.g., concentration of cutaneous carotenoids and the collagen/elastin index (SAAID, was investigated in vivo. A significant average increase from 2.67 ± 0.86 arb. units to 3.25 ± 0.93 arb. units (p < 0.001 in the cutaneous carotenoid concentration was detected subsequent to oral application of the carotenoid-containing Spirulina platensis powder, showing a significant improvement of the antioxidant status of the skin. A slight but not significant increase (p = 0.33 in the dermal SAAID mean values was measured from −0.54 ± 0.11 to −0.51 ± 0.11 subsequent to oral intake of Spirulina platensis powder.

  4. Synthetic polyester from algae oil.

    Science.gov (United States)

    Roesle, Philipp; Stempfle, Florian; Hess, Sandra K; Zimmerer, Julia; Río Bártulos, Carolina; Lepetit, Bernard; Eckert, Angelika; Kroth, Peter G; Mecking, Stefan

    2014-06-23

    Current efforts to technically use microalgae focus on the generation of fuels with a molecular structure identical to crude oil based products. Here we suggest a different approach for the utilization of algae by translating the unique molecular structures of algae oil fatty acids into higher value chemical intermediates and materials. A crude extract from a microalga, the diatom Phaeodactylum tricornutum, was obtained as a multicomponent mixture containing amongst others unsaturated fatty acid (16:1, 18:1, and 20:5) phosphocholine triglycerides. Exposure of this crude algae oil to CO and methanol with the known catalyst precursor [{1,2-(tBu2 PCH2)2C6H4}Pd(OTf)](OTf) resulted in isomerization/methoxycarbonylation of the unsaturated fatty acids into a mixture of linear 1,17- and 1,19-diesters in high purity (>99 %). Polycondensation with a mixture of the corresponding diols yielded a novel mixed polyester-17/19.17/19 with an advantageously high melting and crystallization temperature.

  5. Parasites in algae mass culture

    Directory of Open Access Journals (Sweden)

    Todd William Lane

    2014-06-01

    Full Text Available Parasites are now known to be ubiquitous across biological systems and can play an important role in modulating algal populations. However, there is a lack of extensive information on their role in artificial ecosystems such as algal production ponds and photobioreactors. Parasites have been implicated in the demise of algal blooms. Because individual mass culture systems often tend to be unialgal and a select few algal species are in wide scale application, there is an increased potential for parasites to have a devastating effect on commercial scale monoculture. As commercial algal production continues to expand with a widening variety of applications, including biofuel, food and pharmaceuticals, the parasites associated with algae will become of greater interest and potential economic impact. A number of important algal parasites have been identified in algal mass culture systems in the last few years and this number is sure to grow as the number of commercial algae ventures increases. Here, we review the research that has identified and characterized parasites infecting mass cultivated algae, the techniques being proposed and or developed to control them, and the potential impact of parasites on the future of the algal biomass industry.

  6. Halogenated compounds from marine algae.

    Science.gov (United States)

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-08-09

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.

  7. Bioethanol Production from Indigenous Algae

    Directory of Open Access Journals (Sweden)

    Madhuka Roy

    2015-02-01

    Full Text Available Enhanced rate of fossil fuel extraction is likely to deplete limited natural resources over short period of time. So search for alternative fuel is only the way to overcome this problem of upcoming energy crisis. In this aspect biofuel is a sustainable option. Agricultural lands cannot be compromised for biofuel production due to the requirement of food for the increasing population. Certain species of algae can produce ethanol during anaerobic fermentation and thus serve as a direct source for bioethanol production. The high content of complex carbohydrates entrapped in the cell wall of the microalgae makes it essential to incorporate a pre-treatment stage to release and convert these complex carbohydrates into simple sugars prior to the fermentation process. There have been researches on production of bioethanol from a particular species of algae, but this work was an attempt to produce bioethanol from easily available indigenous algae. Acid hydrolysis was carried out as pre-treatment. Gas Chromatographic analysis showed that 5 days’ fermentation by baker’s yeast had yielded 93% pure bioethanol. The fuel characterization of the bioethanol with respect to gasoline showed comparable and quite satisfactory results for its use as an alternative fuel.DOI: http://dx.doi.org/10.3126/ije.v4i1.12182International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15, page: 112-120  

  8. Photobioreactors for mass cultivation of algae.

    Science.gov (United States)

    Ugwu, C U; Aoyagi, H; Uchiyama, H

    2008-07-01

    Algae have attracted much interest for production of foods, bioactive compounds and also for their usefulness in cleaning the environment. In order to grow and tap the potentials of algae, efficient photobioreactors are required. Although a good number of photobioreactors have been proposed, only a few of them can be practically used for mass production of algae. One of the major factors that limits their practical application in algal mass cultures is mass transfer. Thus, a thorough understanding of mass transfer rates in photobioreactors is necessary for efficient operation of mass algal cultures. In this review article, various photobioreactors that are very promising for mass production of algae are discussed.

  9. Toxic Effects of Phthalates on Ocean Algae

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This article discusses the interaction of phthalates and ocean algae based on the standard appraisal method of chemical medicine for algae toxicity. Through the experiments on the toxic effects of dimethyl (o-) phthalate (DMP), diethyl (o-) phthalate (DEP), dibutyl (o-)phthalate (DBP) on ocean algae, the 50 % lethal concentration of the three substances in 48 h and 96 h for plaeodectylum tricornutum, platymonas sp, isochrysis galbana, and skeletonema costatum is obtained. Tolerance limits of the above ocean algae of DMP, DEP, and DBP are discussed.

  10. 呼伦贝尔沙地不同植被恢复模式对土壤固氮微生物多样性的影响%Effects of different vegetation restoration patterns on the diversity of soil nitrogen-fixing microbes in Hulunbeier sandy land, Inner Mongolia of North China

    Institute of Scientific and Technical Information of China (English)

    李刚; 王丽娟; 李玉洁; 乔江; 张海芳; 宋晓龙; 杨殿林

    2013-01-01

    利用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术及扩增产物序列分析方法,研究了经过4年不同植被恢复模式下呼伦贝尔沙地土壤固氮微生物的nifH基因多样性和群落结构的变化.结果表明:不同植被恢复模式间土壤固氮微生物群落组成差异显著.混播柠条+羊柴+冰草+披碱草模式(ACHE)下的土壤固氮微生物nifH基因多样性指数最高,其次为混播柠条+冰草(AC)、单播柠条(UC)、单播冰草(UA)和单播羊柴(UH)模式,对照(裸地)最低.除单播羊柴(UH)模式与对照的多样性指数差异不显著外,其余4种植被恢复模式均显著高于对照.单一恢复模式(UA、UH、UC)下,绝大多数土壤固氮微生物属于蓝藻门,结构比较单一;而混播模式(AC和ACHE)下,土壤固氮微生物组成发生明显变化,以变形菌门为主,还包含蓝藻门,其种类增加,多样性提高.不同植被恢复模式的速效磷(AP)、全磷(TP)、全氮(TN)和硝态氮(N03-N)对固氮微生物区系的影响均达到显著水平,且AP、TP、TN和NO3--N之间均具有显著相关性.不同植被恢复模式下土壤固氮微生物区系组成的变化是不同理化因子之间相互关联、共同影响的结果.%By using polymerase chain reaction-denaturing gradient gel electrophoresis (PCRDGGE) and sequence analysis,this paper studied the nifH gene diversity and community structure of soil nitrogen-fixing microbes in Hulunbeier sandy land of Inner Mongolia under four years management of five vegetation restoration modes,i.e.,mixed-planting of Agropyron cristatum,Hedysarum fruticosum,Caragana korshinskii,and Elymus nutans (ACHE) and of Agropyron cristatum and Hedysarum fruticosum (AC),and mono-planting of Caragana korshinskii (UC),Agropyron cristatum (UA),and Hedysarumfruticosum (UH),taking the bare land as the control (CK).There existed significant differences in the community composition of nitrogen-fixing microbes among the five vegetation

  11. EFFECTS OF LIGHT, DENATURANTS AND pH ON ANTIOXIDANT ACTIVITY OF APC IN BLUE GREEN ALGA SPIRULINA PLATENSIS%光照、变性剂和pH对钝顶螺旋藻(Spirulina platensis)别藻蓝蛋白(APC)抗氧化活性的影响

    Institute of Scientific and Technical Information of China (English)

    周站平; 刘鲁宁; 陈秀兰; 张熙颖; 张玉忠; 周百成

    2005-01-01

    采用不同光照条件、不同浓度的十二烷基硫酸钠(SDS)和脲,以及不同pH等条件处理钝顶螺旋藻别藻蓝蛋白(APC),检测其光谱变化、生成及清除自由基能力的变化,对纯化的钝顶螺旋藻别藻蓝蛋白(APC)在不同条件下的抗氧化活性进行了研究.结果表明,光照下,APC具有生成自由基的能力;黑暗中,APC却表现为清除自由基.SDS是一种很强的变性剂,1mmol/L的SDS即可以使APC完全变性,能量传递功能丧失,光照下,APC生成自由基的能力丧失,自由基清除能力明显增强.1.6mol/L的脲作用后,只使APC部分变性,导致APC能量传递效率降低,光照下,表现为生成自由基的能力下降.随着脲浓度的升高(3.2mol/L、6.4mol/L),APC的结构逐渐变化,能量传递功能逐渐丧失,表现为生成自由基的能力逐渐下降,清除自由基的功能逐渐增强.APC具有较宽的pH稳定性,在pH为7-10的范围内非常稳定;当pH为11时,APC的结构已经发生变化.在日光灯下,pH为7时,APC具有生成自由基的能力;pH为8时,APC的荧光光谱虽然没有发生变化,但它们表现为清除自由基的能力.随着pH的增加,自由基清除能力也增强.因此,APC具有产生和清除自由基的双重功能,光照是调控自由基清除与产生的关键因素,并且只有APC具有能量吸收和传递功能时,才具有产生自由基的能力.脱辅基蛋白变性后,清除自由基的能力加强.

  12. Cultivation of macroscopic marine algae

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J.H.

    1982-11-01

    The red alga Gracilaria tikvahiae may be grown outdoors year-round in central Florida with yields averaging 35.5 g dry wt/m/sup 2/.day, greater than the most productive terrestrial plants. This occurs only when the plants are in a suspended culture, with vigorous aeration and an exchange of 25 or more culture volumes of enriched seawater per day, which is not cost-effective. A culture system was designed in which Gracilaria, stocked at a density of 2 kg wet wt/m/sup 2/, grows to double its biomass in one to two weeks; it is then harvested to its starting density, and anaerobically digested to methane. The biomass is soaked for 6 hours in the digester residue, storing enough nutrients for two weeks' growth in unenriched seawater. The methane is combusted for energy and the waste gas is fed to the culture to provide mixing and CO/sub 2/, eliminating the need for aeration and seawater exchange. The green alga Ulva lactuca, unlike Gracilaria, uses bicarbonate as a photosynthesis carbon source, and can grow at high pH, with little or no free CO/sub 2/. It can therefore produce higher yields than Gracilaria in low water exchange conditions. It is also more efficiently converted to methane than is Gracilaria, but cannot tolerate Florida's summer temperatures so cannot be grown year-round. Attempts are being made to locate or produce a high-temperature tolerant strain.

  13. Algae commensal community in Genlisea traps

    Directory of Open Access Journals (Sweden)

    Konrad Wołowski

    2011-01-01

    Full Text Available The community of algae occurring in Genlisea traps and on the external traps surface in laboratory conditions were studied. A total of 29 taxa were found inside the traps, with abundant diatoms, green algae (Chlamydophyceae and four morphotypes of chrysophytes stomatocysts. One morphotype is described as new for science. There are two ways of algae getting into Genlisea traps. The majority of those recorded inside the traps, are mobile; swimming freely by flagella or moving exuding mucilage like diatoms being ablate to colonize the traps themselves. Another possibility is transport of algae by invertebrates such as mites and crustaceans. In any case algae in the Genlisea traps come from the surrounding environment. Two dominant groups of algae (Chladymonas div. and diatoms in the trap environment, show ability to hydrolyze phosphomonoseters. We suggest that algae in carnivorous plant traps can compete with plant (host for organic phosphate (phosphomonoseters. From the spectrum and ecological requirements of algal species found in the traps, environment inside the traps seems to be acidic. However, further studies are needed to test the relations between algae and carnivorous plants both in laboratory conditions and in the natural environment. All the reported taxa are described briefly and documented with 74 LM and SEM micrographs.

  14. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savceno, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent; Veerman, Frits; Frank, J.; van der Mei, R.; den Boer, A.; Bosman, J.; Bouman, N.; van Dam, S.; Verhoef, C.

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runo water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a

  15. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savcenco, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent; Veerman, Frits

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runoff water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a

  16. Take a Dip! Culturing Algae Is Easy.

    Science.gov (United States)

    James, Daniel E.

    1983-01-01

    Describes laboratory activities using algae as the organisms of choice. These include examination of typical algal cells, demonstration of alternation of generations, sexual reproduction in Oedogonium, demonstration of phototaxis, effect of nitrate concentration on Ankistrodesmus, and study of competition between two algae in the same environment.…

  17. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savceno, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent; Veerman, Frits; Frank, J.; van der Mei, R.; den Boer, A.; Bosman, J.; Bouman, N.; van Dam, S.; Verhoef, C.

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runo water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a v

  18. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; Sar, van der Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savceno, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; Schans, van der Martin; Timperio, Vincent; Veerman, Frits; Frank, J.; van der Mei, R.; den Boer, A.; Bosman, J.; Bouman, N.; van Dam, S.; Verhoef, C.

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runo water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a v

  19. Vanadium in marine mussels and algae

    Energy Technology Data Exchange (ETDEWEB)

    Sperling, K.R.; Bahr, B. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany); Ott, J. [Fachhochschule Hamburg (Germany). Fachbereich Naturwissenschaftliche Technik, Studiengang Biotechnologie

    2000-01-01

    A method is presented which is sensitive enough for the determination of vanadium (V) in marine organisms such as mussels and algae. It was sufficiently checked by a reference material and it was applied to V determination in blue mussels and brown algae from the German Bight. (orig.)

  20. Composting of waste algae: a review.

    Science.gov (United States)

    Han, Wei; Clarke, William; Pratt, Steven

    2014-07-01

    Although composting has been successfully used at pilot scale to manage waste algae removed from eutrophied water environments and the compost product applied as a fertiliser, clear guidelines are not available for full scale algae composting. The review reports on the application of composting to stabilize waste algae, which to date has mainly been macro-algae, and identifies the peculiarities of algae as a composting feedstock, these being: relatively low carbon to nitrogen (C/N) ratio, which can result in nitrogen loss as NH3 and even N2O; high moisture content and low porosity, which together make aeration challenging; potentially high salinity, which can have adverse consequence for composting; and potentially have high metals and toxin content, which can affect application of the product as a fertiliser. To overcome the challenges that these peculiarities impose co-compost materials can be employed.

  1. Potential biomedical applications of marine algae.

    Science.gov (United States)

    Wang, Hui-Min David; Li, Xiao-Chun; Lee, Duu-Jong; Chang, Jo-Shu

    2017-06-03

    Functional components extracted from algal biomass are widely used as dietary and health supplements with a variety of applications in food science and technology. In contrast, the applications of algae in dermal-related products have received much less attention, despite that algae also possess high potential for the uses in anti-infection, anti-aging, skin-whitening, and skin tumor treatments. This review, therefore, focuses on integrating studies on algae pertinent to human skin care, health and therapy. The active compounds in algae related to human skin treatments are mentioned and the possible mechanisms involved are described. The main purpose of this review is to identify serviceable algae functions in skin treatments to facilitate practical applications in this high-potential area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Advances in genetic engineering of marine algae.

    Science.gov (United States)

    Qin, Song; Lin, Hanzhi; Jiang, Peng

    2012-01-01

    Algae are a component of bait sources for animal aquaculture, and they produce abundant valuable compounds for the chemical industry and human health. With today's fast growing demand for algae biofuels and the profitable market for cosmetics and pharmaceuticals made from algal natural products, the genetic engineering of marine algae has been attracting increasing attention as a crucial systemic technology to address the challenge of the biomass feedstock supply for sustainable industrial applications and to modify the metabolic pathway for the more efficient production of high-value products. Nevertheless, to date, only a few marine algae species can be genetically manipulated. In this article, an updated account of the research progress in marine algal genomics is presented along with methods for transformation. In addition, vector construction and gene selection strategies are reviewed. Meanwhile, a review on the progress of bioreactor technologies for marine algae culture is also revisited. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Algae inhibition experiment and load characteristics of the algae solution

    Science.gov (United States)

    Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

    2016-08-01

    It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

  4. Isolation of Nitrogen-Fixing Bacteria and Phosphate-Solubilizing Bacteria from the Rhizosphere of Mangrove Plants and Their Enhancement to the Growth of Kandelia candel Seedlings%红树林固氮菌和解磷菌的分离及对秋茄苗的促生效果

    Institute of Scientific and Technical Information of China (English)

    何雪香; 李玫; 廖宝文

    2012-01-01

    Fifty nine isolates of nitrogen-fixing bacteria and phosphate-solubilizing bacteria were isolated based on the characteristics of morphology and growth of the bacteria on the selective growth media from the rhizosphere of mangrove plants including Bruguiera gymnorhiza, B. Sexangula, Kandelia candel, Rhizophora stylosa, Sonneratia apetala and S. Caseolaris in Zhanjiang and Zhuhai, Guangdong Province and Dongzhai harbor, Hainan Island. Among them 7 isolates of nitrogen-fixing bacteria and 8 isolates of phosphate-solubilizing bacteria were screened as propagule inoculants of K. Candel in a series of potted experiments to examine their capability to promote the growth of plants. The results showed that the inoculation with a single isolate of phosphate-solubilizing bacteria He4# resulted in a significant increase in plant height, root mass and total biomass at the rate of 58.4% , 132. 1% and 133. 2% , respectively. The enhancement of isolate He4# on the plant growth is more significant than that of an alien isolate (Bacillus lichenciformis). The root biomass and total biomass of K. Candel inoculated He4# increased by 72. 7% and 90. 2% than those inoculated B. Lichenciformis. All pure inoculations with 7 different isolates of nitrogen-fixing bacteria showed positive response to the plant growth, and the inoculation with isolateNgqq-R14 resulted in the maximum increase in plant height, stem diameter, stem dry mass, root dry mass and total biomass at the rate of 38. 36% , 16. 19% , 75. 46% , 51. 55% and 59. 31% , respectively. Dual inoculations with 7 mixtures of one isolate of nitrogen-fixing bacteria and one isolate of phos-phate-solubilizing bacteria could result in synergistic effect on the growth of the seedlings of K. Candel, and the increase of plant height, stem dry mass, root dry mass and total biomass were 21. 1% -69. 4% , 70. 7% -271. 3% , 27. 1% - 111. 3% and 66. 9% - 123. 8% respectively. It can be concluded that u-sing mixed cultures of microorganisms is

  5. Isolation and Phylogeny of Nitrogen-Fixing Endophytic Bacteria in Wheat, Rice, Maize, Chinese Cabbage and Celery%小麦、水稻、玉米、白菜、芹菜内生固氮菌及其系统发育

    Institute of Scientific and Technical Information of China (English)

    孙建光; 罗琼; 高淼; 胡海燕; 徐晶; 周义清

    2012-01-01

    [目的]了解小麦、水稻、玉米、白菜、芹菜内生固氮菌的主要类群,确定内生固氮菌的系统发育地位.[方法]样品表面灭菌后采用无氮培养基分离、培养内生固氮菌,乙炔还原法测定菌株固氮酶活性;PCR扩增得到菌株16S rDNA,通过序列测定和相似性分析研究菌株的系统发育.[结果]从大田小麦体内分离到内生固氮菌34株,固氮酶活性在0.30-30.24 nmol C2H4/h·mg蛋白,基于16S rDNA序列最大相似性,这些菌株分属于假单胞菌(Pseudomonas)、根瘤菌(Rhizobium)、芽孢杆菌(Bacillus)、黄杆菌(Fla vobac terium)等13属21种,种群分布较为广泛;从大田水稻体内分离到内生固氮菌25株,固氮酶活性在3.12-254.12 nmol C2H4/h·mg蛋白,属于芽孢杆菌、伯克霍尔德氏菌(Burkholderia)、肠杆菌(Enterobacter)、克雷伯氏菌(Klebsiella)等9属16种,伯克霍尔德氏菌、肠杆菌和克雷伯氏菌是水稻内生固氮菌特有种群;从大田玉米体内分离到内生固氮菌9株,固氮酶活性在7.27-59.58 nmol C2H4/h·mg蛋白,属于根瘤菌、鞘氨醇单胞菌(Sphingomonas)等5属6种;从盆栽试验小白菜体内分离到内生固氮菌14株,固氮酶活性在2.33-205.21 nmol GH4/h·mg蛋白,属于根瘤菌、节杆菌(Arthrobacter)等6属8种;从市售芹菜体内分离到内生固氮菌10株,固氮酶活性在1.23-46.70nmolC2H4/h·mg蛋白,属于鞘氨醇单胞菌、假单胞菌等5属8种.[结论]在生长期小麦、水稻、玉米和部分蔬菜体内普遍存在内生固氮菌,菌株固氮酶活性差异较大,在0.30-254.12 nmol C2H4/h·mg蛋白,系统发育地位分属于假单胞菌、根瘤菌、芽孢杆菌等25个属的56个种,这些内生固氮菌对于农业生产有巨大潜能.%[Objective] The objective of this study is to determine the main groups and phylogenetic position of nitrogen-fixing endophytic bacteria in wheat, rice, maize, Chinese cabbage and celery. [Method] Surface sterilization and

  6. Effects of a nitrogen fixing plant Vigna radiata on growth, leaf stomatal gas exchange and hy-draulic characteristics of the intercropping Juglans regia seedlings%固氮植物绿豆对核桃幼苗生长、叶片气孔气体交换及水力特征的作用

    Institute of Scientific and Technical Information of China (English)

    张翠萍; 孟平; 张劲松; 万贤崇

    2014-01-01

    Aims Our main purposes were to determine the effects of Vigna radiata, a nitrogen fixing plant, on growth, wa-ter balance and gas exchange of the intercropping Juglans regia seedlings and to investigate the hydraulic mecha-nism involved in photosynthesis and growth. Methods We measured growth, hydraulic characteristics, and rate of gas exchange in J. regia seedlings, and ana-lyzed the effects of the intercropping nitrogen fixing V. radiata on xylem anatomic structure, water balance and photosynthetic characteristics of J. regia seedlings under conditions of nitrogen deprivation and enrichment. Important findings Under conditions of nitrogen deficiency, the nitrogen fixing V. radiata facilitated the growth of the intercropping J. regia seedlings by improving xylem development, water transport and hydraulic character-istics in high transpiration demand. However, with nitrogen addition, the occurrence of V. radiata inhibited the growth of J. regia seedlings, likely by competing for water and other elements.%采用砂培方法,在温室内将一年生核桃(Juglans regia)嫁接苗木和绿豆(Vigna radiata)进行间作,研究绿豆对核桃苗木生长、水分平衡和光合特性的影响。该研究设有5种处理,即:对照(核桃单作,正常供应氮素);核桃单作,不添加氮素;核桃绿豆间作,不添加氮素;核桃绿豆间作,正常供应氮素;绿豆单作,不添加氮素。结果显示:种植绿豆可以增加土壤氮含量和核桃茎内氮含量,但对核桃叶和根系中的氮含量影响不明显。种植绿豆显著增加不施氮核桃的高生长和直径生长,但降低了正常供氮核桃的生长。无论种植绿豆与否,不供氮处理降低了核桃的总叶面积,提高了根冠比。核桃叶片气孔气体交换对各处理的响应和生长有相同的趋势。缺氮显著降低了核桃叶柄在中午的导水率、提高了导水损失率;种植绿豆显著提高不供氮核桃的导水率

  7. DGDG and Glycolipids in Plants and Algae.

    Science.gov (United States)

    Kalisch, Barbara; Dörmann, Peter; Hölzl, Georg

    2016-01-01

    Photosynthetic organelles in plants and algae are characterized by the high abundance of glycolipids, including the galactolipids mono- and digalactosyldiacylglycerol (MGDG, DGDG) and the sulfolipid sulfoquinovosyldiacylglycerol (SQDG). Glycolipids are crucial to maintain an optimal efficiency of photosynthesis. During phosphate limitation, the amounts of DGDG and SQDG increase in the plastids of plants, and DGDG is exported to extraplastidial membranes to replace phospholipids. Algae often use betaine lipids as surrogate for phospholipids. Glucuronosyldiacylglycerol (GlcADG) is a further glycolipid that accumulates under phosphate deprived conditions. In contrast to plants, a number of eukaryotic algae contain very long chain polyunsaturated fatty acids of 20 or more carbon atoms in their glycolipids. The pathways and genes for galactolipid and sulfolipid synthesis are largely conserved between plants, Chlorophyta, Rhodophyta and algae with complex plastids derived from secondary or tertiary endosymbiosis. However, the relative contribution of the endoplasmic reticulum- and plastid-derived lipid pathways for glycolipid synthesis varies between plants and algae. The genes for glycolipid synthesis encode precursor proteins imported into the photosynthetic organelles. While most eukaryotic algae contain the plant-like galactolipid (MGD1, DGD1) and sulfolipid (SQD1, SQD2) synthases, the red alga Cyanidioschyzon harbors a cyanobacterium-type DGDG synthase (DgdA), and the amoeba Paulinella, derived from a more recent endosymbiosis event, contains cyanobacterium-type enzymes for MGDG and DGDG synthesis (MgdA, MgdE, DgdA).

  8. Algae Biofuel in the Nigerian Energy Context

    Science.gov (United States)

    Elegbede, Isa; Guerrero, Cinthya

    2016-05-01

    The issue of energy consumption is one of the issues that have significantly become recognized as an important topic of global discourse. Fossil fuels production reportedly experiencing a gradual depletion in the oil-producing nations of the world. Most studies have relatively focused on biofuel development and adoption, however, the awareness of a prospect in the commercial cultivation of algae having potential to create economic boost in Nigeria, inspired this research. This study aims at exploring the potential of the commercialization of a different but commonly found organism, algae, in Nigeria. Here, parameters such as; water quality, light, carbon, average temperature required for the growth of algae, and additional beneficial nutrients found in algae were analysed. A comparative cum qualitative review of analysis was used as the study made use of empirical findings on the work as well as the author's deductions. The research explored the cultivation of algae with the two major seasonal differences (i.e. rainy and dry) in Nigeria as a backdrop. The results indicated that there was no significant difference in the contribution of algae and other sources of biofuels as a necessity for bioenergy in Nigeria. However, for an effective sustainability of this prospect, adequate measures need to be put in place in form of funding, provision of an economically-enabling environment for the cultivation process as well as proper healthcare service in the face of possible health hazard from technological processes. Further studies can seek to expand on the potential of cultivating algae in the Harmattan season.

  9. 21 CFR 73.185 - Haematococcus algae meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Haematococcus algae meal. 73.185 Section 73.185... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.185 Haematococcus algae meal. (a) Identity. (1) The color additive haematococcus algae meal consists of the comminuted and dried cells of the alga...

  10. Collection, Isolation and Culture of Marine Algae.

    Science.gov (United States)

    James, Daniel E.

    1984-01-01

    Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)

  11. Role of marine algae in organic farming

    Digital Repository Service at National Institute of Oceanography (India)

    Pereira, N.; Verlecar, X.N.

    As the efforts to unearth new sources for organic farming accelerate, one needs to evaluate the options available. Marine algae popularly known as seaweeds, have served mankind from times immemorial. form. Seaweed-based fertilizer is rich in growth...

  12. Dipeptides from the red alga Acanthopora spicifera

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; DeSouza, L.; Kamat, S.Y.

    An investigation of red alga Acanthophora spicifera afforded the known peptide, aurantiamide acetate and a new diastereoisomer of this dipeptide (dia-aurantiamide acetate). This is a first report of aurantiamide acetate from a marine source...

  13. 2011 Biomass Program Platform Peer Review: Algae

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Joyce [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2012-02-01

    This document summarizes the recommendations and evaluations provided by an independent external panel of experts at the 2011 U.S. Department of Energy Biomass Program’s Algae Platform Review meeting.

  14. Thraustochytrid fungi associated with marine algae

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.

    of these diatoms but grew only on senescent moribund cultures. Some of the macroalgae collected from Kavarathi atoll of Lakshadweep islands also harboured thraustochytrid fungi. Contrary to other reports these thraustochytrids were found on living healthy algae...

  15. Antioxidant Activity of Hawaiian Marine Algae

    Directory of Open Access Journals (Sweden)

    Anthony D. Wright

    2012-02-01

    Full Text Available Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined. The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer.

  16. Antioxidant activity of Hawaiian marine algae.

    Science.gov (United States)

    Kelman, Dovi; Posner, Ellen Kromkowski; McDermid, Karla J; Tabandera, Nicole K; Wright, Patrick R; Wright, Anthony D

    2012-02-01

    Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined. The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power) assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer.

  17. Carotenoids in Algae: Distributions, Biosyntheses and Functions

    Directory of Open Access Journals (Sweden)

    Shinichi Takaichi

    2011-06-01

    Full Text Available For photosynthesis, phototrophic organisms necessarily synthesize not only chlorophylls but also carotenoids. Many kinds of carotenoids are found in algae and, recently, taxonomic studies of algae have been developed. In this review, the relationship between the distribution of carotenoids and the phylogeny of oxygenic phototrophs in sea and fresh water, including cyanobacteria, red algae, brown algae and green algae, is summarized. These phototrophs contain division- or class-specific carotenoids, such as fucoxanthin, peridinin and siphonaxanthin. The distribution of α-carotene and its derivatives, such as lutein, loroxanthin and siphonaxanthin, are limited to divisions of Rhodophyta (macrophytic type, Cryptophyta, Euglenophyta, Chlorarachniophyta and Chlorophyta. In addition, carotenogenesis pathways are discussed based on the chemical structures of carotenoids and known characteristics of carotenogenesis enzymes in other organisms; genes and enzymes for carotenogenesis in algae are not yet known. Most carotenoids bind to membrane-bound pigment-protein complexes, such as reaction center, light-harvesting and cytochrome b6f complexes. Water-soluble peridinin-chlorophyll a-protein (PCP and orange carotenoid protein (OCP are also established. Some functions of carotenoids in photosynthesis are also briefly summarized.

  18. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    Science.gov (United States)

    Holzinger, Andreas; Allen, Michael C; Deheyn, Dimitri D

    2016-09-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal objects to study adaptation to high light irradiation. Here, we used a detailed description of the spectral properties as a proxy for photo-acclimation/protection in snow algae (Chlamydomonas nivalis, Chlainomonas sp. and Chloromonas sp.) and charophyte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorption spectra of these microalgae in the waveband of 400-900nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance between 400-550nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this high absorbance was missing, the latter being close relatives to land plants. To investigate if cellular water loss has an influence on the spectral properties, the cells were plasmolysed in sorbitol or desiccated at ambient air. While in snow algae, these treatments did hardly change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400-500nm. These changes might be ecologically relevant and photoprotective, as aeroterrestrial algae are naturally exposed to occasional water limitation, leading to desiccation, which are conditions usually occurring together with higher irradiation.

  19. Algae production for energy and foddering

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Attila; Jobbagy, Peter; Durko, Emilia [University of Debrecen, Faculty of Applied Economics and Rural Development (UD-FAERD), Centre for Agricultural and Applied Economic Sciences, Debrecen (Hungary)

    2011-09-15

    This study not only presents the results of our own experiments in alga production, but also shows the expected economic results of the various uses of algae (animal feed, direct burning, pelleting, bio-diesel production), the technical characteristics of a new pelleting method based on literature, and also our own recommended alga production technology. In our opinion, the most promising alternative could be the production of alga species with high levels of oil content, which are suitable for utilization as by-products for animal feed and in the production of bio-diesel, as well as for use in waste water management and as a flue gas additive. Based on the data from our laboratory experiments, of the four species we analyzed, Chlorella vulgaris should be considered the most promising species for use in large-scale experiments. Taking expenses into account, our results demonstrate that the use of algae for burning technology purposes results in a significant loss under the current economic conditions; however, the utilization of algae for feeding and bio-diesel purposes - in spite of their innovative nature - is nearing the level needed for competitiveness. By using the alga production technology recommended by us and described in the present study in detail, with an investment of 545 to 727 thousand EUR/ha, this technology should be able to achieve approximately 0-29 thousand EUR/ha net income, depending on size. More favorable values emerge in the case of the 1-ha (larger) size, thanks to the significant savings on fixed costs (depreciation and personnel costs). (orig.)

  20. Algae Biofuel in the Nigerian Energy Context

    Directory of Open Access Journals (Sweden)

    Elegbede Isa

    2016-05-01

    Full Text Available The issue of energy consumption is one of the issues that have significantly become recognized as an important topic of global discourse. Fossil fuels production reportedly experiencing a gradual depletion in the oil-producing nations of the world. Most studies have relatively focused on biofuel development and adoption, however, the awareness of a prospect in the commercial cultivation of algae having potential to create economic boost in Nigeria, inspired this research. This study aims at exploring the potential of the commercialization of a different but commonly found organism, algae, in Nigeria. Here, parameters such as; water quality, light, carbon, average temperature required for the growth of algae, and additional beneficial nutrients found in algae were analysed. A comparative cum qualitative review of analysis was used as the study made use of empirical findings on the work as well as the author’s deductions. The research explored the cultivation of algae with the two major seasonal differences (i.e. rainy and dry in Nigeria as a backdrop. The results indicated that there was no significant difference in the contribution of algae and other sources of biofuels as a necessity for bioenergy in Nigeria. However, for an effective sustainability of this prospect, adequate measures need to be put in place in form of funding, provision of an economically-enabling environment for the cultivation process as well as proper healthcare service in the face of possible health hazard from technological processes. Further studies can seek to expand on the potential of cultivating algae in the Harmattan season.