Blue-green Alga Anabaena Cylindrica Research Articles

The Iinfluence of Lead Ions on the Assimilation of Ammonium in the Blue-Green Alga Anabaena cylindrica Lemm

The Iinfluence of Lead Ions on the Assimilation of Ammonium in the Blue-Green Alga Anabaena cylindrica Lemm

Nitrogen-fixing inhibition by KCl in a blue-green algaAnabaena cylindrica

Growing in the medium containing 0.10 mol/L KCl for three days, the nitrogen-fixing activity ofAnabaena cylindrica decreased by 95%. Extent of the inhibition was enchanced with increased KCl concentrations. The biggest decrease of nitrogen-fixing activity was between 0.02–0.05 mol/L KCl. The same decline on growth was between 0.05–0.10 mol/L KCl. The longer treating-time was, the lower nitrogen-fixing activity was. A short time of KCl-treatment (for 4 h) resulted in 66.4% decrease of the activity. Under effecting of KCl for three days, the frequency of heterocyst differentiation decreased from 7.2% to 2.1%.

Nitrogen isotope ratios of red tide organisms in the East China Sea: A characterization of biological nitrogen fixation

Nitrogen isotope fractionation in the process of N 2 fixation was examined in detail by culturing the blue green alga Anabaena cylindrica. The δ 15N value of the alga was almost constant ( − 0.6 ± 0.9‰ on average) irrespective of growth conditions, similar to other N 2 fixing microorganisms previously reported. Nitrogen isotope ratios of marine plankton from the East China Sea have been studied to evaluate the contribution of N 2 fixation to the red tide organisms, predominated by the N 2 fixing blue-green alga Trichodesmium spp. The δ 15N of Trichodesmium ( − 2.1 to + 1.0‰) showed the same range of that estimated if the biological atmospheric N 2 fixation was the main nitrogen source of the red tide organisms. Mixed plankton collected by towing a phytoplankton net (96 μm) gave from 2 to 4‰ higher δ 15N than that of sorted phytoplankton. Zooplankton and fish collected from the same red tide area showed systematic enrichment of 15N along the food chain, and exhibited relatively lower δ 15N than previous results for zooplankton from other regions, reflecting biological N 2 fixation. The δ 15N of mixed plankton in the surface seawater from 32°N to 20°N latitude along 125°E longitude decreased from 6 to 1‰. A symmetrical relation was found between the horizontal distribution of δ 15N of plankton, the concentration of Trichodesmium and the trend of salinity.

Occurrence of glutamine-2-oxoacid transaminase activity in the blue-green alga Anabaena cylindrica.

Aspartate and glutamate were formed from glutamine and oxaloacetate with crude enzyme extracts obtained by ammonium sulfate precipitation (35-65% saturation) from the blue-green alga Anabaena cylindrica. In this reaction the 2-amino group of glutamine was transferred to oxaloacetate in the absence of a reluctant. Azaserine, an inhibitor of glutamine -amide transfer, inhibited glutamate formation from glutamine but did not inhibit aspartate formation. Thus, a transamination from glutamine directly to oxaloacetate was indicated. This transamination reaction may be accomplished with glutamine-2-oxoacid transaminase which is found in animal tissues and in yeast.

Hydrogen evolution by photobleached Anabaena cylindrica

We have studied the evolution of hydrogen by photobleached filaments of the heterocystous bluegreen alga Anabaena cylindrica. The photobleached cells became orange-yellow due to the heavy accumulation of carotenoids. We found that the yellow filaments produced much larger amounts of hydrogen than the normal, green ones, while the nitrogenase activity responsible for hydrogen evolution increased to a lesser extent. We suggest that a reversible hydrogenase activity induced in photobleached filaments is responsible for the excess amount of hydrogen. 3-(3',4'-dichlorophenyl)-1,1-dimethyl urea (DCMU) inhibits the hydrogen evolution of the yellow filaments which produce much more oxygen and fix less CO2 than the green filaments. Therefore we consider the water to be a possible electron source for this hydrogenase. The low efficiency of light energy conversion (0.3%) in nitrogenase-catalyzed H2 evolution (Laczkó, 1980 Z. Pflanzenphysiol. 100, 241-245) is increased to 1.5-2% by the appearance of the reversible hydrogenase activity.

Immunological studies with nitrogenase from Azotobacter and bacterial nitrate reductases

Antibodies raised to purified Component I of nitrogenase (Mo-Fe-S) protein from Azotobacter vinelandii cross-reacted not only with this protein but also with nitrate reductases from a number of bacteria. Antibodies raised for a purified nitrate reductase from Escherichia coli also formed precipitin bands with this Component I of nitrogenase. Antibodies to Component I, however, did not react with nitrate reductases from either a blue-green alga Anabaena cylindrica or with higher plants, or with aldehyde dehydrogenase and xanthine oxidase from animal sources.

Anaerobic and Aerobic Hydrogen Gas Formation by the Blue-Green Alga Anabaena cylindrica

An investigation was made of certain factors involved in the formation of hydrogen gas, both in an anaerobic environment (argon) and in air, by the blue-green alga Anabaena cylindrica. The alga had not been previously adapted under hydrogen gas and hence the hydrogen evolution occurred entirely within the nitrogen-fixing heterocyst cells; organisms grown in a fixed nitrogen source, and which were therefore devoid of heterocysts, did not produce hydrogen under these conditions. Use of the inhibitor dichlorophenyl-dimethyl urea showed that hydrogen formation was directly dependent on photosystem I and only indirectly dependent on photosystem II, consistent with heterocysts being the site of hydrogen formation. The uncouplers carbonyl cyanide chlorophenyl hydrazone and dinitrophenol almost completely inhibited hydrogen formation, indicating that the process occurs almost entirely via the adenosine 5'-triphosphate-dependent nitrogenase. Salicylaldoxime also inhibited hydrogen formation, again illustrating the necessity of photophosphorylation. Whereas hydrogen formation could usually only be observed in anaerobic, dinitrogen-free environments, incubation in the presence of the dinitrogen-fixing inhibitor carbon monoxide plus the hydrogenase inhibitor acetylene resulted in significant formation of hydrogen even in air. Hydrogen formation was studied in batch cultures as a function of age of the cultures and also as a function of culture concentration, in both cases the cultures being harvested in logarithmic growth. Hydrogen evolution (and acetylene-reducing activity) exhibited a distinct maximum with respect to the age of the cultures. Finally, the levels of the protective enzyme, superoxide dismutase, were measured in heterocyst and vegetative cell fractions of the organism; the level was twice as high in heterocyst cells (2.3 units/mg of protein) as in vegetative cells (1.1 units/mg of protein). A simple procedure for isolating heterocyst cells is described.

The utilization of molecular hydrogen by the blue-green alga Anabaena cylindrica

The blue-green alga Anabaena cylindrica is found to consume molecular hydrogen in a hydrogenase dependent reaction. This hydrogen uptake proceeds in the dark and is strictly dependent on oxygen, thus representing a Knallgas reactions. Its rate is almost as high as that of the endogenous respiration in Anabaena. Studies with inhibitors reveal that hydrogen is utilized via the complete respiratory chain providing additional energy for the alga. CO plus C2H2 completely block the Knallgas reaction which explains the previously reported considerable increase in the total H2 formation representing the difference between the nitrogenase-dependent H2-evolution and the reutilization of the gas catalysed by the hydrogenase in intact Anabaena.

Effect of 7-Azatryptophan on Nitrogen Fixation and Heterocyst Formation in the Blue-green Alga Anabaena cylindrica

In the blue-green alga Anabaena caienula, 7-azatryptophan was shown to alter the pattern of heterocyst formation in two ways: (a) the number of these specialized cells is increased, (b) groups of adjacent heterocysts are formed. The present communication extends these observations on the morphological changes to the blue-green alga Anabaena cylindrica . Moreover, nitrogen fixation activities are observed to increase parallel with the formation of new heterocysts when Anabaena is grown in the presence of 1—5, µ M azatryptophan indicating that the heterocysts are the main site of nitrogenase in these aerobically grown cultures. Kinetic studies show that azatryptophan first affects nitrogen fixation. This inhibition is followed by an increase in the number of heterocysts and finally by a recovery of the nitrogen fixation activity beyond that of control algae grown without the tryptophan analogue. Azatryptophan specifically inhibits nitrogen fixation in Anabaena, since it does not affect ammonia-grown Anabaena cylindrica or nitrogen fixing Klebsiella pneumoniae .

The hydrogenase-nitrogenase relationship in the blue-green algaAnabaena cylindrica

Nitrogen-fixingAnabaena cylindrica cells are found to evolve hydrogen in high quantities in the presence of CO plus C2H2. Studies with the inhibitors dichlorophenyldimethylurea (DCMU), disalicylidenepropanediamine (DSPD), dibromothymoquinone (DBMIB), undecylbenzimidazole (UDB) and chloro-carbonyl-cyanide-phenylhydrazone (CCCP) and also withAnabaena grown on nitrate- and ammonia-nitrogen show that the H2-formation is due to the ATP-dependent H3O(+)-reduction catalysed by nitrogenase. In control experiments CO plus C2H2 inhibited the activities of a cell-free hydrogenase fromClostridium pasteurianum. It is concluded that Anabaena has a hydrogenase whose natural function is to recycle the H2 lost by the action of nitrogenase.

Carbon dioxide assimilation in blue-green algae: initial studies on the structure of ribulose 1,5-bisphosphate carboxylase.

D-Ribulose 1,5-bisphosphate carboxylase was purified from the blue-green alga Anabaena cylindrica (Lemm) by procedures involving acid precipitation, ammonium sulfate fractionation, and Sephadex G-200 gel filtration. The enzyme was homogeneous by the criterion of polyacrylamide disc gel electrophoresis and was a multimer of a single-size polypeptide chain of 54,000 daltons. The carboxylases from four species of blue-green algae (Anabaena, Nostoc strain MAC, Agmenellum quadruplicatum strain PR-6, and Anacystis nidulans strain TX20) were closely similar in molecular size, since enzyme activity was eluted at the same volume after sucrose gradient centrifugation. Further analysis by gel filtration indicated that the four blue-green algal carboxylases were nearly identical in molecular weight, ranging from 449 to 453,000. The amino acid composition of the Anabaena carboxylase was determined and was found to resemble closely the composition of the large subunit from eukaryotic photosynthetic organisms.

Substance stimulating the differentiation of spores of the blue-green alga Cylindrospermum licheniforme.

THE study of intercellular inductions in higher plants and animals is hindered by the complexity of the multicellular tissues involved. Sporulation of filamentous blue-green algae is a relatively simple process to study because these algae contain, in linear array, only three types of cells. There are vegetative cells, and heterocysts and spores which form by differentiation of vegetative cells. Wolk1,2 showed that heterocysts of the blue-green alga Anabaena cylindrica Lemm. induce adjacent vegetative cells to differentiate into spores. We report here that a substance produced by the related alga, Cylindrospermum licheniforme, greatly stimulates sporulation of that same alga.

Photosynthetic electron transport, ATP synthesis and nitrogenase activity in isolated heterocysts of Anabaena cylindrica

Isolated heterocysts of the N 2-fixing blue-green alga Anabaena cylindrica contain the Photosystem I components P-700, bound and soluble ferredoxins and ferredoxin-NADP reductase. They also show Photosystem I activity being able to photoreduce both methylviologen and NADP when ascorbate+dichlorophenol-indophenol acts as reductant. They photophosphorylate (64 μmol ATP produced/mg chlorophyll a h ) and carry out oxidative phosphorylation (8.7 μmol ATP produced/mg chlorophyll a h ). Ninety per cent of the total cell-free extract nitrogenase activity is located in the heterocyst fraction of aerobic cultures.

Polyhedral bodies and ribulose 1,5-diphosphate carboxylase of the blue-green alga Anabaena cylindrica

The ribulose 1,5-diphosphate carboxylase (RUDP Case E.C. 4.1.1.39) activity of late log phase Anabaena cylindrica Lemm. was measured in vitro in fractions obtained by sucrose density gradient centrifugation. Two peaks of enzymic activity were obtained. One, accounting for about 80% of the total measurable activity occurred at the top of the gradient and appeared to be soluble activity; the second showed maximum activity in the 55% (w/w) sucrose fraction and represented 20% of the total activity. When the distribution of RUDP Case was assayed by immunoprecipitation using antiserum to RUDP Case from Euglena gracilis, the corresponding values were 59% and 41%. Electron microscopy of the various fractions showed that polyhedral bodies, which are sites of RUDP Case activity in other autotrophic prokaryotes, were also most abundant in the 55% (w/w) sucrose fraction.

Effects of L-methionine-DL-sulphoximine on the assimilation of newly fixed NH 3, acetylene reduction and heterocyst production in Anabaena cylindrica

The addition of exogenous L-methionine-DL-sulphoximine (MSO) to N 2-fixing cultures of the blue-green alga Anabaena cylindrica results in over half of the newly fixed NH 3 being released into the medium. MSO also inhibits glutamine synthetase (GS) activity, has negligible effect on alanine dehydrogenase activity, and glutamate dehydrogenase activity under N 2-fixing conditions is negligible. In the presence of MSO, intracellular pools of glutamate and glutamine decrease, those of aspartate and alanine + glycine show little change, and the NH 3 pool increases. MSO alleviates the inhibitory effect of exogenous NH 4 + on nitrogenase synthesis and heterocyst production. The results suggest that in N 2-fixing cultures of A. cylindrica the primary NH 3 assimilating pathway involves GS, and probably glutamate synthase (GOGAT), and that the repressor of nitrogenase synthesis and heterocyst production is not NH 4 + but is GS, GOGAT, or a product of their reactions.

Hydrogen Evolution by Nitrogen-Fixing Anabaena cylindrica Cultures

Actively growing, nitrogen-fixing cultures of the blue-green alga Anabaena cylindrica can simultaneously evolve hydrogen and oxygen frolni water and light. Hydrogen evolution was strongly inhibited by N(2) but only slightly by CO or O(2), characteristics of the nitrogenase reaction in the heterocysts of Anabaena cylindrica. We suggest that this reaction has potential use in solar energy conversion.

On the reversibility of heterocyst differentiation

Heterocyst development in the blue-green alga Anabaena cylindrica Lemm. was arrested by ammonia at an early stage of differentiation only. No dedifferentiation or germination of heterocysts in the presence of ammonia could be detected.

Properties and function of the pyruvate: ferredoxin oxidoreductase from the blue-green alga Anabaena cylindrica.

Extracts from the nitrogen fixing blue-green algaAnabaena cylindrica catalyse a pyruvate decarboxylation, which is dependent on ferredoxin and stimulated by coenzyme A, ATP and a SH-protecting compound. This pyruvate clastic reaction is completely reversible: The net synthesis of pyruvate requires CO2, acetyl-coenzyme A and reduced ferredoxin. Preparations fromAnabaena cylindrica also catalyse the exchange reaction between CO2 and the carboxyl group of pyruvate. Thus the enzyme fromAnabaena cylindrica has essentially all the characteristics known for the pyruvate: ferredoxin oxidoreductase from anaerobic bacteria.

Cytochrome c reducing substances in photosynthetic electron transport.

Abstract Photosynthetic cytochrome c reduction by isolated chloroplasts is mediated by substances with characteristics of a "Cytochrome c Reducing Substance" (CRS). A water soluble extract of ether treated, lyophilized chloroplasts (called Sʟ-eth), related to the primary acceptor complex of photo­ system I, has CRS-activity. It contains p-coumaroyl-meso-tartaric acid. By comparison with model substances, the CRS-activity in chloroplasts is attributed to the iron complex of this compound. A number of other iron complexes and numerous quinones with redox potentials from - 220 mV to + 300 mV are also shown to possess CRS-activity. The CRS preparation from the blue green alga Anabaena cylindrica, as first described by Fujita and Myers, contains Fe3+/EDTA, which has all the chemical and functional properties as reported for CRS

The detection of a bound ferredoxin in the photosynthetic lamellae of blue-green algae and other oxygen evolving photosynthetic organisms

The presence of an electron transport component with an EPR spectrum similar to that of a ferredoxin has been demonstrated in the blue-green alga Anabaena cylindrica , the green alga Euglena gracilis , and in chloroplasts from sorghum ( Sorghum bicolour ) and beans ( Phaseolus vulgaris ). The component is photoreduced at 77°K and is very similar to that previously reported in spinach. It seems likely that this component is a primary electron acceptor in photosynthesis in all of these organisms.