| quantitative and qualitative dna variations in anabaena azollae strasb. living in azolla filiculoides lam. | heterocysts and vegetative cells of the filamentous nitrogen-fixing anabaena azollae isolated from the apex to the basal leaf cavities of azolla filiculoides were examined by epifluorescent microscope after fluorochrome staining. acridine orange (ao), dapi, and chromomycin fluorochromes were used in order to evidence total dna content and respectively, a + t and g + c bases. measurements of fluorescence intensities were made on photographic prints by the automatic image analysis system quantimet ... | 1992 | 1374307 |
| indole-3-acetic acid (iaa) production by arthrobacter species isolated from azolla. | arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species azolla pinnata and azolla filiculoides, produced indole-3-acetic acid (iaa) in culture when the precursor tryptophan was added to the medium. no iaa production was detected in the absence of tryptophan. maximum iaa formation was obtained in the first 2 d of incubation. part of the tryptophan was transformed to n alpha-acetyl-l-tryptophan. | 1992 | 1564446 |
| immunocytochemical localization of nitrogenase in bacteria symbiotically associated with azolla spp. | in situ immunogold labeling and transmission electron microscopy were used to detect nitrogenase in bacteria (bactobionts) symbiotically associated with leaf cavities of azolla caroliniana and azolla filiculoides. in a. caroliniana, the fe protein of the nitrogenase complex was detected in a subset of the distinct bactobiont types present in leaf cavities of all ages. similar results were obtained for the bactobionts of a. filiculoides with antisera against both the fe and mofe subunits of nitro ... | 1991 | 1785936 |
| toxicity of tributyltin to lemna minor l. and azolla filiculoides lamk. | | 1998 | 9470996 |
| evaluation of the fern azolla for growth, nitrogen and phosphorus removal from wastewater. | water fern (azolla filiculoides lam.) has been assessed for nitrogen and phosphorus removal in outdoor experiments comparing sewage water (s) from an experimental aquaculture plant, well water (w) and mineral growth medium hoagland (h). the experiments were undertaken during the spring and the summer. the yield of fern biomass and nitrogenase activity was higher in h than in w and s waters. the enzyme activity had a decreasing trend with significant differences (p < 0.05) in the three waters. pe ... | 2001 | 11317907 |
| azolla-anabaena symbionts and microbial mat as nitrogen-fixing biocatalysts for bioregenerative space life support. | this study was conducted to characterize the responses of selected nitrogen-fixing biocatalysts to various environmental parameters that are likely to be encountered in a scaled-up nitrogen-fixing bioregenerative unit for use in a biologically based life support system (blss). the results showed that while both azolla filiculoides and azolla nilotica thrived on standard nitrogen-free liquid media, only azolla filiculoides maintained its growth rate in the presence of 50% by volume of aerobic-bio ... | 1998 | 11871445 |
| performance of dead azolla filiculoides biomass in biosorption of au from wastewater. | dried milled biomass of azolla filiculoides removed up to 98.2% of gold from wastewater from a gold plating factory containing 5 mg gold/l in solution in batch biosorption. the gold uptake capacity of the biomass was 98 mg/g. whole dried biomass used in a continuous flow column removed up to 100% of gold from diluted wastewater. a similar column was linked to a sulphide precipitation process to provide a two-step system which was able to remove 98% of gold from undiluted wastewater containing 41 ... | 2006 | 16369874 |
| can we predict community-wide effects of herbicides from toxicity tests on macrophyte species? | macrophyte communities play an essential role in the way freshwater ecosystems function. it is thus of great concern to understand how environmental factors, especially anthropogenic ones, influence their composition and diversity. the aim of this study was to examine whether the effects of a herbicide mixture (50% atrazine, 35% isoproturon, 15% alachlor) on single macrophyte species can be used to predict its impact at a community level. in a first experiment we tested the sensitivity of six sp ... | 2010 | 20926143 |
| aquatic arsenic: phytoremediation using floating macrophytes. | phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumulating plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. both terrestrial and aquatic plants have been tested to remediate contaminated soi ... | 2011 | 21435676 |
| biting midges (diptera: ceratopogonidae) from martín garcía island, argentina. | nearly 230 species of biting midges have been recorded or described from argentina; 38 of them are known from the buenos aires province and only one is cited from martín garcía island. this paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these envi ... | 2011 | 22017124 |
| the use of water lettuce (pistia stratiotes l.) for rhizofiltration of a highly polluted solution by cadmium and lead. | the effectiveness of heavy metal uptake from contaminated nutrient solution by four aquatic macrophytes (pistia stratiotes l., salvinia auriculata aubl, salvinia minima baker, and azolla filiculoides lam) was estimated in this study. the influence of cadmium (3.5 mg l(-1) and 10.5 mg l(-1)) and lead (25 mg l(-1) and 125 mg l(-1)) on the stress symptoms was observed through the determination of chlorophyll content and transpiration rate over 14 days of the experiment. the results of the present s ... | 2011 | 21972509 |
| genome erosion in a nitrogen-fixing vertically transmitted endosymbiotic multicellular cyanobacterium. | an ancient cyanobacterial incorporation into a eukaryotic organism led to the evolution of plastids (chloroplasts) and subsequently to the origin of the plant kingdom. the underlying mechanism and the identities of the partners in this monophyletic event remain elusive. | 2010 | 20628610 |
| differentiation of mis 9 and mis 11 in the continental record: vegetational, faunal, aminostratigraphic and sea-level evidence from coastal sites in essex, uk. | multidisciplinary investigations of the vegetational, faunal and sea-level history inferred from the infills of buried channels on the coast of eastern essex have a direct bearing on the differentiation of mis 11 and mis 9 in continental records. new data are presented from cudmore grove, an important site on mersea island that can be linked to the terrace sequence of the river thames. the vegetational history has been reconstructed from a pollen sequence covering much of the interglacial repres ... | 2009 | 20119485 |
| biotechnological potential of azolla filiculoides for biosorption of cs and sr: application of micro-pixe for measurement of biosorption. | the presence of cs and sr in culture medium of azolla filiculoides caused about 27.4% and 46.3% inhibition of biomass growth, respectively, in comparison to a. filiculoides control weight which had not metals. biosorption batch experiments were conducted to determine the cs and sr binding ability of native biomass and chemically modified biosorbents derived from azolla namely ferrocyanide azolla sorbents type 1 and type 2 (fas1 and fas2) and hydrogen peroxide azolla sorbent (has). the best cs an ... | 2009 | 19054668 |
| response of growth and antioxidant enzymes in azolla plants (azolla pinnata and azolla filiculoides) exposed to uv-b. | effect of ultravilolet-b (0.4 wm(-2)) irradiation on growth, flavonoid content, lipid peroxidation, proline accumulation and activities of superoxide dismutase and peroxidase was comparatively analysed in azolla pinnata and azolla filiculoides. growth measured as increment in dry weight reduced considerably due to all uv-b treatments. however, the reduction was found to be severe in a. filiculoides as compared to a. pinnata. the level of uv-absorbing compound flavonoids increased significantly i ... | 2008 | 18637563 |
| arsenic accumulation by the aquatic fern azolla: comparison of arsenate uptake, speciation and efflux by a. caroliniana and a. filiculoides. | this study investigates as accumulation and tolerance of the aquatic fern azolla. fifty strains of azolla showed a large variation in as accumulation. the highest- and lowest-accumulating ferns among the 50 strains were chosen for further investigations. azolla caroliniana accumulated two times more as than azolla filiculoides owing to a higher influx velocity for arsenate. a. filiculoides was more resistant to external arsenate due to a lower uptake. both strains showed a similar degree of tole ... | 2008 | 18457908 |
| proteomic analysis of the cyanobacterium of the azolla symbiosis: identity, adaptation, and nifh modification. | cyanobacteria are able to form stable nitrogen-fixing symbioses with diverse eukaryotes. to extend our understanding of adaptations imposed by plant hosts, two-dimensional gel electrophoresis and mass spectrometry (ms) were used for comparative protein expression profiling of a cyanobacterium (cyanobiont) dwelling in leaf cavities of the water-fern azolla filiculoides. homology-based protein identification using peptide mass fingerprinting [matrix-assisted laser desorption ionization-time of fli ... | 2008 | 18065763 |
| a mercury(ii) ion-selective electrode based on n,n-dimethylformamide-salicylacylhydrazone as a neutral carrier. | a new pvc membrane mercury(ii) ion electrode based on n,n-dimethylformamide-salicylacylhydrazone (dmfas) as an ionophore is described, which shows excellent potentiometric response characteristics and displays a linear log[hg(2+)] versus emf response over a wide concentration range between 6.2 x 10(-7) and 8.0 x 10(-2) m with a nerstian slope of 29.6 mv per decade and a detection limit of 5.0 x 10(-7) m. the response time for the electrode is less than 30 s and the electrode can be used for more ... | 2006 | 16760602 |
| superoxide dismutase in the symbiont anabaena azollae strasb. | superoxide dismutase was investigated in the symbiont anabaena azollae strasb. living in azolla filiculoides lam. in vegetative cells, three isoenzymatic forms of superoxide dismutase, containing manganese, iron, and the hybrid iron-manganese, respectively, were present. hybrid superoxide dismutase, detected for the first time in cyanobacteria, was 7% of the total superoxide dismutase present in vegetative cells. all three superoxide dismutase forms increased in the anabaena vegetative cells obt ... | 1991 | 16668392 |
| localization and toxic effects of cadmium, copper, and uranium in azolla. | the storage and distribution of copper, cadmium, and uranium and their effects on ionic contents in roots and shoots of azolla filiculoides has been studied by x-ray microanalysis. the relative content of copper was eightfold higher in the root than in the shoot, suggesting low mobility of this metal in azolla plant. cadmium relative content in the shoot was similar to its content in the root, hence its mobility was relatively high. the absence of significant uranium quantities in the shoot and ... | 1988 | 16666274 |
| a cobalt requirement for symbiotic growth of azolla filiculoides in the absence of combined nitrogen. | cobalt was shown to be essential for the symbiotic growth of azolla filiculoides and anabacna azollac in the absence of fixed nitrogen. addition of 0.01 mug/liter cobalt resulted in large increases in yield, chlorophyll content and nitrogen fixation as compared to control cultures without cobalt. cobalt was not required for the growth of azolla when nitrate nitrogen was supplied. the number of anabaena azollae cells in the fronds of azolla appeared to be decreased by ommission of cobalt from the ... | 1966 | 16656330 |
| dna probes show genetic variation in cyanobacterial symbionts of the azolla fern and a closer relationship to free-living nostoc strains than to free-living anabaena strains. | twenty-two isolates of anabaena azollae derived from seven azolla species from various geographic and ecological sources were characterized by dna-dna hybridization. cloned dna fragments derived from the genomic sequences of three different a. azollae isolates were used to detect restriction fragment length polymorphism among all symbiotic anabaenas. dna clones were radiolabeled and hybridized against southern blot transfers of genomic dnas of different isolates of a. azollae digested with restr ... | 1990 | 16348182 |
| azolla filiculoides nitrogenase activity decrease induced by inoculation with chlamydomonas sp. | experiments were conducted to determine the influence of chlamydomonas sp. on nitrogen fixation (c(2)h(2) --> c(2)h(4)) in azolla filiculoides and on the nitrogen fixation and growth of free-living anabaena azollae 2b organisms. inoculation of azolla medium with chlamydomonas sp. was associated with decreased nitrogenase activity in a. filiculoides and with increases in the density of a fungal population identified as acremonium sp. subsequent inoculation of azolla medium with this fungus was al ... | 1986 | 16347211 |
| kinetic modeling and thermodynamic study to remove pb(ii), cd(ii), ni(ii) and zn(ii) from aqueous solution using dead and living azolla filiculoides. | dead azolla filiculoides can remove pb(2+),cd(2+), ni(2+) and zn(2+) corresponding to second-order kinetic model. the maximum adsorption capacity (q(max)) to remove these metal ions by the alkali and cacl(2)/mgcl(2)/nacl (2:1:1, molar ratio) activated azolla from 283 to 313k was 1.431-1.272, 1.173-0.990, 1.365-1.198 and 1.291-0.981mmol/g dry biomass, respectively. q(max) to remove these heavy metals by the non-activated azolla at the mentioned temperature range was obtained 1.131-0.977, 1.092-0. ... | 2006 | 16325335 |
| characterization and expression of a metallothionein gene in the aquatic fern azolla filiculoides under heavy metal stress. | a cdna encoding a type 2 metallothionein (mt) was isolated from azolla filiculoides, termed azmt2, accession no. af482470. the azmt2 transcript was expressed in sterile a. filiculoides that were free of the cyanobiont anabaena azollae after erythromycin treatment, proving that azmt2 is encoded by the fern genome. azmt2 rna expression was enhanced by the addition of cd(+2), cu(+2), zn(+2) and ni(+2) to the growth medium. the transcript level of azmt2 correlated with the metal content in the plant ... | 2005 | 16133213 |
| pre-treatment processes of azolla filiculoides to remove pb(ii), cd(ii), ni(ii) and zn(ii) from aqueous solution in the batch and fixed-bed reactors. | intact and treated biomass can remove heavy metals from water and wastewater. this study examined the ability of the activated, semi-intact and inactivated azolla filiculoides (a small water fern) to remove pb(2+), cd(2+), ni(2+) and zn(2+) from the aqueous solution. the maximum uptake capacities of these metal ions using the activated azolla filiculoides by naoh at ph 10.5 +/- 0.2 and then cacl(2)/mgcl(2)/nacl with total concentration of 2 m (2:1:1 mole ratio) in the separate batch reactors wer ... | 2005 | 16111810 |
| batch and column studies on biosorption of acid dyes on fresh water macro alga azolla filiculoides. | the biosorption of acid red 88 (ar88), acid green 3 (ag3) and acid orange 7 (ao7) by deactivated fresh water macro alga azolla filiculoides was investigated in batch mode. langmuir and freundlich adsorption models were used for the mathematical description of the batch biosorption equilibrium data and model constants were evaluated. the adsorption capacity was ph dependent with a maximum value of 109.0 mg/g at ph 7 for ar88, 133.5 mg/g at ph 3 for ag3 and 109.6 mg/g at ph 3 for ao7, respectively ... | 2005 | 15955624 |
| phylogeny of symbiotic cyanobacteria within the genus nostoc based on 16s rdna sequence analyses. | a phylogenetic analysis of selected symbiotic nostoc strain sequences and available database 16s rdna sequences of both symbiotic and free-living cyanobacteria was carried out using maximum likelihood and bayesian inference techniques. most of the symbiotic strains fell into well separated clades. one clade consisted of a mixture of symbiotic and free-living isolates. this clade includes nostoc sp. strain pcc 73102, the reference strain proposed for nostoc punctiforme. a separate symbiotic clade ... | 2005 | 15549268 |
| localization of glutamine synthetase isoforms in hair cells of azolla leaves. | immunoelectron microscopy and a quantitative analysis of immunogold labeling of a glutamine synthetase (gs; ec 6.3.1.2) revealed that, in mesophyll cells of mature leaves of azolla filiculoides, almost all gs was present in chloroplasts. by contrast, in hair cells, abundant labeling of gs was observed both in chloroplasts and in the cytoplasm. in hair cells of cyanobiont-free plants, the labeling of gs of both chloroplasts and cytoplasm was very weak compared to that of cyanobiont-containing pla ... | 2004 | 15356334 |
| lead accumulation in the aquatic fern azolla filiculoides. | in this study, we characterized lead (pb2+) accumulation and storage by the aquatic fern azolla filiculoides. lead precipitates were detected in the vacuoles of mesophyll cells of azolla plants cultured for 6 d in rich growth medium containing 20 mg l(-1) pb2+. energy dispersive spectroscopy (eds) analysis of the relative element content of leaves collected from these plants revealed a 100% increase in the levels of p, s, na and ca and a 40% decrease in mg and cl compared to the untreated plants ... | 2004 | 15331093 |
| l-myo-inositol 1-phosphate synthase in the aquatic fern azolla filiculoides. | l-myo-inositol 1-phosphate synthase (inps ec 5.5.1.4) catalyzes the conversion of d-glucose 6-phosphate to l-myo-inositol 1-phosphate. inps is a key enzyme involved in the biosynthesis of phytate which is a common form of stored phosphates in higher plants. the present study monitored the increase of inps expression in azolla filiculoides resulting from exposure to inorganic phosphates, metals and salt stress. the expression of inps was significantly higher in azolla plants that were grown in ri ... | 2004 | 15283124 |
| synergistic effect of deoxyanthocyanins from symbiotic fern azolla spp. on hrma gene induction in the cyanobacterium nostoc punctiforme. | the hrma gene of the n2-fixing cyanobacterium nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. here, we report that anthocyanins can contribute to induction of hrma expression. aqueous extract from fronds of the fern azolla pinnata, a host of symbiotic nostoc spp., was found to be a potent inducer of hrma-luxab in n. punctiforme strain ucd 328. the hrma-luxab inducing activities of a. pinnata, as ... | 2002 | 12236594 |
| sulphadimethoxine and azolla filiculoides lam.: a model for drug remediation. | plants can be an interesting tool for in situ remediation of drug contaminated waters. in a laboratory model azolla filiculoides lam., an aquatic fern known to absorb pollutants, has been exposed to an environmental persistent antibiotic commonly used in intensive farming, sulphadimethoxine (s), to test its bioremediation capability. in a 5 week experiment, plants were cultivated outdoor at four drug concentrations (50, 150, 300 and 450 mg l(-1)) in n-free mineral medium. drug affects growth rat ... | 2002 | 12188140 |
| abscission of azolla branches induced by ethylene and sodium azide. | treatment with ethylene accelerated the abscission of branches of azolla filiculoides plants. an azolla plantlet treated with ethylene at 10 microl liter(-1) divided into 4-5 fragments after a lag period of 6-8 h. ethylene-induced abscission was effectively inhibited by cycloheximide and was associated with an increase in the activities of cellulase and polygalacturonase. at the fracture surface abscised after treatment with ethylene, dissolution of the primary walls of the abscission zone cells ... | 2000 | 11134422 |
| identification of a common cyanobacterial symbiont associated with azolla spp. through molecular and morphological characterization of free-living and symbiotic cyanobacteria. | symbiotically associated cyanobacteria from azolla mexicana and azolla pinnata were isolated and cultured in a free-living state. morphological analyses revealed differences between the free-living isolates and their symbiotic counterparts, as did restriction fragment length polymorphism (rflp) analyses with both single-copy glna and rbcs gene probes and a multicopy psba gene probe. rflp analyses with anabaena sp. strain pcc 7120 nifd excision element probes, including an xisa gene probe, detect ... | 1991 | 1685078 |
| stress responses of duckweed (lemna minor l.) and water velvet (azolla filiculoides lam.) to anionic surfactant sodium-dodecyl-sulphate (sds). | surfactants are used for several purposes and recently they have attracted the attention for their ability to modify the behavior of other preexistent or co-disposed contaminants, although their use or discharge in wastewaters can represent a real or potential risk for the environment. lemna minor l. and azolla filiculoides lam. are floating aquatic macrophytes, very effective in accumulating several pollutants including sodium dodecyl sulphate (sds). in this work we evaluated the effects of sds ... | 2011 | 22277247 |