Blue-green Alga Nostoc Muscorum Research Articles

Comparative study on phycoremediation performance of three native microalgae for primary-treated municipal wastewater

The current study was aimed to investigate the performance of three native microalgae in primary-treated municipal wastewater with regard to their nutrient removal, water quality improvement for reuse, and in vivo Chl-a -based biomass production. The microalgae species belonged to three different taxonomic classes, namely blue–green blue-green algae Nostoc muscorum , diatom Navicula veneta , and green microalgae Chlorella vulgaris . The comparative phytoremediation potentials of the microalgae species and the consortium were evaluated for 7 days-exponential growth phase employed in the batch systems. The results showed that the interaction between in vivo Chl-a concentration and residual concentration of TN, TP, and COD was notable. COD, TN, and TP treatment efficiencies were in the ranges of (85.7–95.7%), (72–96.9%), and (86.07–99.8%), respectively. The final concentrations of TN, TP, and COD in effluent provided by N. veneta treatment complied with EU Directive 91/271, EU Directive COM (2018)337, and national legislation, whereas the results of C. vulgaris partially complied with these legislations. Concerning the phycoremediation efficiency and the growth characteristic of the monoculture and mixed culture of the native microalgae, it was concluded that the monocultures in most cases were superior to the consortium culture. Diatom N. veneta had the highest growth rate (0.88 ± 0.04 day −1 ), Chl-a-biomass yield (50.45 ± 1.5 mg L −1 ), and removal efficiency (96.9 % TN, 99.8 % TP, 95.7 % COD). The results also reveal that the native species effectively reduce TN, TP, and COD concentrations of wastewater, and the diatom N. veneta may be a strong novel candidate for phytoremediation systems. • Three native microalgae were tested for their removal performances of pollutants in pre-treated municipal wastewater. • In vivo Chl-a fluorescence was significantly associated with the residual concentration of TN, TP, and COD. • Diatom Navicula veneta is a novel candidate in the sustainable bioremediation of municipal wastewater. • Phycoremediated municipal wastewater by diatom fulfilled the limit values of EU Directive 91/271 and EU COM(2018) 337.

Salinity–induced modulations in the protective defense system and programmed cell death in Nostoc muscorum

To study the biochemical adaptive responses of the blue green algae Nostoc muscorum to the salinity- induced stress they were exposed to various concentrations (5, 10, 15, 20 or 200 mM) of sodium chloride (NaCl). A dose-dependent inhibition of total protein content showed an adverse effect of NaCl on the growth of N. muscorum. Four-day treatment of NaCl (5–20 mM) progressively increased the content of the total peroxide with subsequent increase of the superoxide dismutase (SOD) activity, proline and total phenol content only up to 10 mM NaCl. Higher concentrations of NaCl caused significant decrease in both the enzymatic and non-enzymatic antioxidants. Induction of two polypeptides of ~29.10 and 40.15 kD as well as upregulation of many polypeptides as compared to control indicates the induction of SOD and dehydrin-like proteins, which supports the theory of adaptation against the salt stress. Furthermore, adaptation of N. muscorum to lower concentrations (5–20 mM) of NaCl was also confirmed by no fragmentation of DNA while DNA fragmentation indicating programmed cell death (PCD) could only be seen at 200 mM NaCl for 12 hours. We hypothesized that proline may confer a positive role to combat salinity stress and the same was confirmed by treatment of the test blue green algae with exogenous proline (1 and 10 μM). The results exhibited 16% reduction in the level of total peroxides, which is a well known oxidative stress marker in the 10 μM proline-treated NaCl group as compared to direct exposure to NaCl.

Phycotoxicity of linear alkylbenzene sulfonate

Dose- and time-dependent effects of linear alkylbenzene sulfonate, a major component of synthetic detergent, to the blue-green alga Nostoc muscorum, were studied under laboratory conditions. Toxicity was evident, at doses above 0.001%, from the decrease in biomass, heterocyst number, and protein content and pathomorphological alterations.

Carbodhydrate composition of a biologically active complex from the blue-green algaNostoc muscorum

Carbodhydrate composition of a biologically active complex from the blue-green algaNostoc muscorum

Potent Mutagenicity of a Bipyridylium Herbicide in a Nitrogen-fixing Blue-green Alga Nostoc muscorum,

The herbicide diquat (1,1′-ethylene-2,2′-bipyridylium ion) has been found to exert a growth inhibitory effect on the N2-fixing blue-green alga Nostoc muscorum in nitrogen-free (N 2 ) and NO 3 - media, without any apparent inhibitory/stimulatory effect on the heterocyst-forming capacity of the organism. With a dose of diquat permitting about 20 and 50% survival of this alga a reverse mutation (from het + nif + auxotrophy to het+ nif+ prototrophy), a forward mutation for L-methionine- DL-sulfoximine (MSO)-resistance, and an auxotrophic mutation for carbon-requirement through methylamine (MA)-resistance, have been obtained. The toxic and mutagenic effects of this agro- chemical have been compared with those of the well known mutagen MNNG (N-methyl-N′-nitro- N-nitrosoguanidine) and found to be stronger than the latter in each case.

Growth ofNostoc muscorum mutants in the presence of diuron (DCMU) and L-methionine-DL-sulfoximine

Diuron (DCMU) is inhibitory to the photoautotrophic and photoheterotrophic growth of the N2-fixing blue-green algaNostoc muscorum at concentrations of 1.0×10−5 M and 2.0×10−5 M, respectively. A mutant of this organism resistant to 5.0×10−5 M DCMU under its photoheterotrophic growth conditions, with the ability to utilize DCMU as a carbon and nitrogen source for growth, and complete inability to grow photoautotrophically has been isolated. With the apparent defect in its photosynthetic ability, it is suggested that theDCMU r mutant lacks the step inhibited by 1.0×10−5 M DCMU, and metabolizes DCMU by an existing enzyme system in the absence of such inhibition. That this enzyme may be glutamine synthetase (GS) is explained with the help of a L-methionine-DL-sulfoximine (MSO)-resistant mutant ofN. muscorum which is able to grow faster with 2.0×10−5 DCMU and is known to contain an altered GS.

Powerful mutagenicity of a bipyridylium herbicide in a nitrogen-fixing blue-green alga Nostoc muscorum

The herbicide, paraquat (1,1′-dimethyl-4,4′-bipyridylium ion), was found to be toxic and lytic to Nostoc muscorum in N 2 (at the expense of elemental nitrogen, i.e. unsupplemented with any combined nitrogen source) and NO 3 − media, without any apparent inhibitory or stimulatory effect on its nitrogen-fixing apparatus, i.e. heterocyst formation. At a dose of paraquat resulting in 20, 50 and 75% survival, induction of reverse mutations (from het − nif − auxotrophy to het + nif + prototrophy), forward mutations (for streptomycin [St]-resistance), and auxotrophic mutations (carbon-auxotrophy through methylamine [MA]-resistance) were observed with frequencies comparable to those obtained through induction with the well known mutagen MNNG ( N-methyl- N′-nitro- N-nitrosoguanidine).

Strong mutagenic action of a bipyridylium herbicide in a N2-fixing blue-green alga

The herbicide paraquat (1,1′-dimethyl-4,4-bipyridylium ion) has been found to exert a growth inhibitory effect on the N2-fixing blue-green algaNostoc muscorum in nitrogen-free (N2) and NO 3 − media, without any apparent inhibitory or stimulatory effect on the heterocyst-forming capacity of the organism. With a dose of paraquat permitting about 20 and 50% survival of this alga a reverse mutation (fromhet + nif − auxotrophy tohet + nif + prototrophy), a forward mutation (for L-methionine-DL-sulfoximine [MSO]-resistance), and an auxotrophic mutation (for carbon-auxotrophy through methylamine [MA]-resistance) have been obtained. The toxic and mutagenic effects of this agrochemical have been compared with those of the well known mutagen MNNG (N-methyl-N′-nitro-N-nitrosoguanidine) and found to be stronger than those of the latter in each case.

Loss of aerobic nitrogen fixation associated with kasugamycin resistance in the heterocystous nitrogen-fixing, streptomycin resistant blue-green alga Nostoc muscorum

Heterocystous N2-fixing, Streptomycin resistant (Het (+)Nif(+)Str-R) Nostoc muscorum produces two groups of Kasugamycin resistant (Kas-R) phenotypes: one group showing normal heterocyst frequency and normal aerobic growth with N2 as a nitrogen source, the other group showing loss of growth with N2 as nitrogen source under aerobic growth conditions. Examination of strains showing Kas-R associated loss of aerobic N2 growth shows them to comprise three classes: Class A showing loss of both heterocyst and nitrogenase activity, class B showing formation of heterocyst but no nitrogenase activity and class C lacking heterocyst but containing microaerobic nitrogenase activity. The three classes of mutants revert to aerobic prototrophy with almost similar frequency of about 10(-6) suggesting them to have arisen as a result of single mutational events. Their reversion to prototrophy is simultaneously accompanied by the loss of Kas-R phenotype. All the phenotypic revertants in general appear more or less similar to the parental strain in respect to heterocyst formation, aerobic N2 growth and Kasugamycin sensitivity (Kas-S).

Sulfide Stimulation of Light-Induced Hydrogen Evolution by the Cyanobacterium Nostoc muscorum

Light-induced hydrogen evolution by the blue-green alga Nostoc muscorum is stimulated by sulfide with a rate of about 20 (μmol H2 per mg chlorophyll and hour stable for about one day at low light intensities (7 W/m2). Oxygen evolution does not impair sulfide-stimulated hydrogen formation. Increased hydrogen evolution is catalyzed by nitrogenase, its activity is not influenced by sulfide. Apparently, sulfide inhibits the hydrogen-uptake pathway(s), thereby increasing net hydrogen evolution. - Furthermore, photosynthetic electron flow is inhibited by sulfide, essentially at the oxidizing side of photosystem II, as was dem onstrated by fluorescence-signal changes. This leads to decreased electron supply of nitrogenase. Hydrogen production apparently is at optim um when both the effect o f sulfide on photosynthesis is moderate and when uptake-hydrogenase activity is abolished

Mo-V interactions during N2- and NO 3 − -metabolism in a N2-fixing blue-green algaNostoc muscorum

Molybdenum (Mo), a group 6B element (applied in the form of sodium molybdate at a concentration of 0.0177 ppm), is required for N2- and NO 3 − -mediated growth ofNostoc muscorum. The amount of growth of such Mo-containing culutures is significantly enhanced by the addition of 0.0125 ppm vanadium (V), an element belonging to group 5 of the periodic table (applied in the form of sodium vanadate). At concentrations above 0.0125 ppm V proves growth-inhibitory toN. muscorum cultured with or without Mo. Mo and/or V exert(s) no apparent stimulatory/inhibitory effect on NO 2 − -mediated growth of the organism.

Physiological and Biochemical Characterization of the Methylamine Resistant (MAR) Mutants of the Blue-Green Alga Nostoc muscorum

Summary In vivo, methylamine (MA) causes inhibition of photosynthetic O2 evolution, phototrophic inhibition of ATP-pool and decrease in the extractable L-methionine-DL-Sulfoximine (MSX) sensitive glutamine synthetase (GS) activity in parental strain of Nostoc muscorum leading finally to its phototrophic inhibition of growth and nitrogenase activity. The observed inhibitory actions of MA are missing from MAR mutant strain of glutamine synthetase (GS) activity in parental strain of N. muscorum due to its ability to metabolize MA through a MA-mediated activation in vivo of an enzyme system functionally similar to MSX sensitive GS of parental strain. MA is unable to inhibit in vitro GS activity of either strain while MSX does inhibit the in vitro as activity but at a concentration considerably higher than that required for in vivo GS inhibition. The results suggest involvement of some in vivo factor or process which normally mediates MA inhibition of as activity in parental strain, but which, as a result of mutation, is functionally changed, mediating MA activation of GS activity in MAR mutant strain, thus causing metabolism of MA leading to relief of its various phototrophic processes from MA inhibition.

Photophosphorylation in isolated heterocysts from the blue-green alga Nostoc muscorum

Isolated heterocysts of the blue-green alga Nostoc muscorum (Anabaena 7119) exhibit high rates of photophosphorylation in systems with cyclic and non-cyclic electron transport. Cyclic photophosphorylation mediated by N-methylphenazonium methosulfate is found to be sensitive to antimycin A, but not to 2,5-dibromo-3-methyl-6-isopropyl- p-benzoquinon (DBMIB). Non-cyclic electron transport (diaminodurol → methylviologen) coupled to phosphorylation is affected by DBMIB, but not by antimycin A. Studies with uncouplers indicate that ΔpH is the main component of the protonmotive force under continuous illumination. A different effect of NH 4Cl on dark- and photophosphorylation is observed and discussed with respect to localization of respiration in blue-green algae.

A pesticide-resistant mutant of the N2-fixing blue-green algaNostoc muscorum

The fungicide dithane Z-78 (zinc ethylene bisdithiocarbamate) has been found to be an inhibitor of growth and heterocyst differentiation inNostoc muscorum. Its inhibitory effect has been reversed by exogenous glucose. A spontaneous mutant resitant to a toxic concentration of the fungicide grows in the presence of dithane at a dose normally applied in fields and does not require an exogenous carbon source for its growth.

An Evolutionary Tree Based on Monoclonal Antibody-Recognized Surface Features of a Plastid Enzyme (5-Aminolevulinate Dehydratase)

Abstract We describe and discuss an evolutionary tree derived from data which were obtained using monoclonal antibodies. Monoclonal antibodies (see e.g. Köhler and Milstein, Nature 256, 495 (1975)) were prepared against 5-aminolevulinate dehydratase (ALAD) from spinach (Spinacia oleracea) and enabled us to study 13 different ALAD antigenic determinant characters from origins as diverse as algae, mosses, ferns, gymnosperms and angiosperms. The results show that a dendrogram based on these characters is largely in accord with evolutionary trees based on classical characters. Species, such as Chara or Gnetum, whose system­atic positions are doubtful, are separated from their alleged relatives. ALAD from the photosynthetic bacterium Rhodopseudomonas spheroides showed antigenic similarities with the plastid ALAD enzyme from spinach, while none of the antibodies against the spinach enzyme reacted with ALAD from the blue-green alga Nostoc muscorum. This finding is relevant to the problem of the origin of plastids and shows that monoclonal antibodies may also provide a new approach to the solution of this problem. The results imply that monoclonal antibodies will prove themselves efficient tools for taxonomic or evolutionary studies.

Mutation in the Blue-green Alga Nostoc muscorum I. Methylamine-resistant Mutants

Summary The blue-green alga Nostoc muscorum and its Em-R het - nif 2 - mutant strains are sensitive to 1 mM concentration of methylamine (MA). MA-toxicity is independent of inorganic nitrogen sources. The Em-R het - nif 2 - mutant strain has been subjected to a mutation for resistance to 5 mM MA. The resulting Em-R M A-R het - nif - mutant strain requires a fixed carbon and nitrogen source for its normal growth and MA is metabolized in this strain as an organic nitrogen and carbon/energy source.

Mutation in the Blue-green Alga Nostoc muscorum II. L-methionine-DL-sulfoximine-resistant Mutants

Summary The blue-green alga Nostoc muscorum and its Em-R het- nif2- mutant are completely sensitive to 15 ppm concentration of L-methionine-DL-sulfoximille (MSO). Growth-toxicity created by MSO is independent of the inorganic nitrogen sources, i.e., NO3-, NO2- and NH4+. The pa.rent N. muscorum does not form heterocysts in inorganic nitrogen media lacking MSO, but does form them in all these media (except glutamine) containing MSO. MSO-R strain does not form heterocysts in NO3-, NO2-, NH4+ or glutamine medium containing or lacking MSO.

Increase of nitrogenase activity in the blue-green alga Nostoc muscorum (Cyanobacterium).

Preincubation of the blue-green alga (cyanobacterium) Nostoc muscorum under hydrogen or argon (nongrowing conditions, neither CO(2) nor N(2) or bound nitrogen present) in the light resulted in a two- to fourfold increase of light-induced hydrogen evolution and a 30% increase of acetylene reduction. Preincubation under the same gases in the dark led to a decrease of both activities. Cultivation of algae under a hydrogen-containing atmosphere (N(2), H(2), CO(2)) increased neither hydrogen nor ethylene evolution by the cells. Formation of both ethylene and hydrogen is due to nitrogenase activity, which apparently was induced by the absence of N(2) or bound nitrogen and not by the presence of hydrogen. Inhibitors of protein biosynthesis prevented the increase of nitrogenase activity. Hydrogen uptake by the cells was almost unaffected under all of these conditions. With either ammonia or chloramphenicol present, nitrogenase activity decreased under growing conditions (i.e., an atmosphere of N(2) and CO(2)). The kinetics of decrease were the same with ammonia or chloramphenicol, which was interpreted as being due to rapid protein breakdown with a half-life of approximately 4 h. The decay of nitrogenase activity caused by chloramphenicol could be counteracted by nitrogenase-inducing conditions, i.e., by the absence of N(2) or bound nitrogen. A cell-free system from preconditioned algae with an adenosine 5'-triphosphate-generating system exhibited the same increase or decrease of nitrogenase activity as the intact cell filaments, indicating that this effect resided in the nitrogenase complex only. We tentatively assume that not the whole nitrogenase complex, but merely a subunit or a special protein with regulatory function, is susceptible to fast turnover.

Components and activity of the photosynthetic electron transport system of intact heterocysts isolated from the blue-green alga Nostoc muscorum

Heterocysts of the blue-gree alga Nostoc muscorum have been isolated by prolonged treatment with lysozyme. Quantitative data are presented which show the occurrence of cytochromes c-553, f-557 and b-563 in heterocysts in amounts comparable to vegetative cells. Particularly the content of the water-soluble cytochrome c-553 can be used to evaluate the intactness of a heterocyst preparation. Cytochrome f-557 has been partially purified and found to be a c-type cytochrome corresponding to cytochrome f of higher plants and other algae. Cytochrome b-559 is present in vegetative cells but not in heterocysts. The content of plastoquinone in heterocysts is reduced to 42% of the amount present in vegetative cells. These data suggest a degradation of Photosystem II during heterocyst differentiation. Measurements of photosynthetic electron transport in heterocysts proved the inability of the photosynthetic apparatus to carry out electron transport with electrons donated by water or diphenylcarbazide. In Tris-washed thylakoids from vegetative cells, however, diphenylcarbazide can act as an electron donor to Photosystem II.

Ferralterin: An iron-sulfur protein functional in enzyme regulation in photosynthesis

The chloroplast new protein factor that was recently shown to link light to the activation of fructose 1,6-bisphosphatase was identified as a previously unrecognized iron-sulfur protein. This protein, given the name “ferralterin,” was purified to homogeneity from spinach leaves and from the blue-green alga (cyanobacterium) Nostoc muscorum. Ferralterin from both sources showed a visible absorption peak at 410nm, a molecular weight of about 30,000 and (provisionally) 4 g-atoms per mole each of nonheme iron and acid labile sulfide. The homogeneous ferralterin preparations catalyzed a light-dependent activation of chloroplast fructose 1,6-bisphosphatase that was dependent only on chlorophyll-containing membranes.