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Sample records for alga chara corallina

  1. [Modeling of hysteresis in pH pattern formation along the cell membrane of algae Chara corallina].

    PubMed

    Lavrova, A I; Pliusnina, T Iu; Bulychev, A A; Riznichenko, G Iu; Rubin, A B

    2005-01-01

    It is known that illumination of the algae Chara corallina results in the formation along the membrane of regions with inhomogeneous distribution of pH. It was shown that, in a particular range of illumination intensities, two states with different pH distribution are realized at one and the same value of light intensity: an entirely homogeneous state and completely formed structures (pattern). The transition from the homogeneous state to the pattern formation takes place at one value of light intensity, and the back transition, at another light intensity, i.e., the hysteresis is observed. This phenomenon was studied by mathematical modeling. The mechanism of hysteresis is discussed.

  2. Bacillus cereus can attack the cell membranes of the alga Chara corallina by means of HlyII.

    PubMed

    Kataev, Anatoly A; Andreeva-Kovalevskaya, Zhanna I; Solonin, Alexander S; Ternovsky, Vadim I

    2012-05-01

    We studied the influence of Bacillus cereus bacteria on cells of the freshwater alga Chara corallina. These bacteria and recombinant Bacillus subtilis strains are capable of producing the secreted toxin HlyII, which changes the electrophysiological parameters of the algal electrically excitable plasma membrane by forming pores. Cooperative incubation of bacterial cells, which carry active hlyII gene, and Chara corallina cells caused a decrease in the resting potential (V(m)) and plasma membrane resistance (R(m)) of algal cells. The efficiency of each strain was commensurable with its ability to produce HlyII. Purified hemolysin II caused a similar effect on V(m) and R(m) of intact and perfused cells. This protein changed the kinetics and magnitude of transient voltage-dependent calcium and calcium-activated chloride currents owing to the formation of additional Ca(2+)-permeable pores in algal cell membrane. Occurrence of the cellulose cell wall with pores 2.1 to 4.6nm in diameter suggests that HlyII molecules reach the plasma membrane surface strictly as monomers.

  3. Membrane Electrical Noise in Chara corallina1

    PubMed Central

    Ross, Stephen; Dainty, Jack

    1986-01-01

    Certain inhibitors have been found to affect the low frequency spectral component of the electrical noise power spectrum in Chara corallina. Application of the ATPase inhibitor N,N′-dicyclohexylcarbodiimide removed the low frequency spectral component, strengthening the case that the component is produced by active proton pumping. Cytocholasin B, which inhibits cyclosis in internodes of C. corallina, removed the low frequency spectral component in a time-dependent fashion which was correlated with the cessation of streaming. The protonophore carbonyl cyanide m-chlorophenylhydrazone did not produce consistent effects on the low frequency spectral component in these cells. PMID:16664898

  4. Proteomic identification of putative plasmodesmatal proteins from Chara corallina.

    PubMed

    Faulkner, Christine R; Blackman, Leila M; Cordwell, Stuart J; Overall, Robyn L

    2005-07-01

    Plasmodesmata are channels that bridge the cell walls of plant cells, allowing regulated transport of molecules between neighbouring cells. We have used a proteomic strategy to identify putative plasmodesmata-associated proteins in the giant-celled green alga Chara corallina. Proteins were extracted from the plasmodesmata-rich nodal complexes and the middle of the long internodal cells, which do not contain plasmodesmata. Comparison of protein spot patterns generated by two-dimensional gel electrophoresis of both the soluble and cell wall fractions from the two cell types was done. Fifty-eight spots that were common to the nodal and internodal soluble fractions were analysed by matrix assisted laser desorption/ionisation-time of flight mass spectrometry, and peptide mass fingerprint data were used to search the database. Matches were made to four of these spots, in each case to housekeeping proteins. Further, a number of nodal specific spots were identified, 11 from the soluble fraction and nine from the wall fraction. These spots were excised from the gels and analysed by liquid chromatography tandem mass spectrometry to obtain peptide sequence. Database searches suggest that these spots include homologues to previously identified plasmodesmata-associated proteins cp-wap13 and heat shock cognate 70, as well as RNA-binding proteins, eukaryotic initiation factor 4A and a beta-1,3-glucanase. Several spots remained unidentified providing exciting new candidate plasmodesmata-associated proteins.

  5. The motility of Chara corallina myosin was inhibited reversibly by 2,3-butanedione monoxime (BDM).

    PubMed

    Funaki, Keisuke; Nagata, Ayumi; Akimoto, Youka; Shimada, Kiyo; Ito, Kohji; Yamamoto, Keiichi

    2004-09-01

    We studied the effects of 2,3-butanedione monoxime (BDM) on the cytoplasmic streaming of Chara corallina and on the motility of myosin prepared from the same plant to examine whether this reagent really affects the plant class XI myosin. It was found that BDM inhibited both cytoplasmic streaming and the motility of myosin at a very similar concentration range (10-100 mM). BDM introduced directly into tonoplast-free cells also inhibited cytoplasmic streaming. These results suggested that effect of BDM on cytoplasmic streaming was exerted through myosin and not through ion channels at least in Chara corallina, though a very high concentration of BDM was required.

  6. Calcium pectate chemistry controls growth rate of Chara corallina.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2006-01-01

    Pectin, a normal constituent of cell walls, caused growth rates to accelerate to the rates in living cells when supplied externally to isolated cell walls of Chara corallina. Because this activity was not reported previously, the activity was investigated. Turgor pressure (P) was maintained in isolated walls or living cells using a pressure probe in culture medium. Pectin from various sources was supplied to the medium. Ca and Mg were the dominant inorganic elements in the wall. EGTA or pectin in the culture medium extracted moderate amounts of wall Ca and essentially all the wall Mg, and wall growth accelerated. Removing the external EGTA or pectin and replacing with fresh medium returned growth to the original rate. A high concentration of Ca2+ quenched the accelerating activity of EGTA or pectin and caused gelling of the pectin, physically inhibiting wall growth. Low pH had little effect. After the Mg had been removed, Ca-pectate in the wall bore the longitudinal load imposed by P. Removal of this Ca caused the wall to burst. Live cells and isolated walls reacted similarly. It was concluded that Ca cross-links between neighbouring pectin molecules were strong wall bonds that controlled wall growth rates. The central role of Ca-pectate chemistry was illustrated by removing Ca cross-links with new pectin (wall "loosening"), replacing vacated cross-links with new Ca2+ ("Ca2+-tightening"), or adding new cross-links with new Ca-pectate that gelled ("gel tightening"). These findings establish a molecular model for growth that includes wall deposition and assembly for sustained growth activity.

  7. Involvement of membrane potential in alkaline band formation by internodal cells of Chara corallina.

    PubMed

    Shimmen, Teruo; Wakabayashi, Akiko

    2008-10-01

    Internodal cells of Chara corallina form alkaline bands on their surface upon illumination via photosynthesis. In the present study, the effect of KCl on alkaline band formation was analyzed. When the extracellular KCl concentration was increased, alkaline band formation was extensively inhibited. Electrophysiological analysis unequivocally showed the need for inner negative membrane potential for alkaline band formation.

  8. Microbodies of the alga Chara.

    PubMed

    Stabenau, Helmut; Säftel, Werner; Winkler, Uwe

    2003-05-01

    Chara fragilis possesses microbodies with a remarkably large size of up to 2 micro m in diameter. Many of the organelles contain huge nucleoids of amorphous material or paracrystalline inclusions. After isolation of the organelles by gradient centrifugation the specific density of the microbodies was determined to be 1.25 g cm-3. Catalase, glycolate oxidase and hydroxypyruvate reductase as well as enzymes of the fatty acid beta-oxidation pathway were demonstrated to be constituents of the microbodies in Chara indicating that they are similar to those in green leaves. The data obtained are in agreement with the view that the Charophyceae and especially the algae in the subgroup of Charales are very closely related to the land plants.

  9. Calcium deprivation disrupts enlargement of Chara corallina cells: further evidence for the calcium pectate cycle.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2012-06-01

    Pectin is a normal constituent of cell walls of green plants. When supplied externally to live cells or walls isolated from the large-celled green alga Chara corallina, pectin removes calcium from load-bearing cross-links in the wall, loosening the structure and allowing it to deform more rapidly under the action of turgor pressure. New Ca(2+) enters the vacated positions in the wall and the externally supplied pectin binds to the wall, depositing new wall material that strengthens the wall. A calcium pectate cycle has been proposed for these sub-reactions. In the present work, the cycle was tested in C. corallina by depriving the wall of external Ca(2+) while allowing the cycle to run. The prediction is that growth would eventually be disrupted by a lack of adequate deposition of new wall. The test involved adding pectate or the calcium chelator EGTA to the Ca(2+)-containing culture medium to bind the calcium while the cycle ran in live cells. After growth accelerated, turgor and growth eventually decreased, followed by an abrupt turgor loss and growth cessation. The same experiment with isolated walls suggested the walls of live cells became unable to support the plasma membrane. If instead the pectate or EGTA was replaced with fresh Ca(2+)-containing culture medium during the initial acceleration in live cells, growth was not disrupted and returned to the original rates. The operation of the cycle was thus confirmed, providing further evidence that growth rates and wall biosynthesis are controlled by these sub-reactions in plant cell walls.

  10. Tension required for pectate chemistry to control growth in Chara corallina.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2007-01-01

    Recent work showed that polygalacturonate (pectate) chemistry controlled the growth rate of the large-celled alga Chara corallina when turgor pressure (P) was normal (about 0.5 MPa). The mechanism involved calcium withdrawal from the wall by newly supplied pectate acting as a chelator. But P itself can affect growth rate. Therefore, pectate chemistry was investigated at various P. A pressure probe varied P in isolated walls, varying the tension on the calcium pectate cross-links bearing the load of P. When soluble pectate was newly supplied, the wall grew irreversibly but the pectate was inactive below a P of 0.2 MPa, indicating that tension was required in the existing wall before new pectate acted. It was suggested that the tension distorted some of the wall pectate (the dominant pectin), weakening its calcium cross-links and causing the calcium to be preferentially lost to the new pectate, which was not distorted. The preferential loss provided a molecular mechanism for loosening the wall structure, resulting in faster growth. However, the resulting relaxation of the vacated wall pectate would cause calcium to be exchanged with load-bearing calcium pectate nearby, auto-propagating throughout the wall for long periods. There is evidence for this effect in isolated walls. In live cells, there is also evidence that auto-propagation is controlled by binding the newly supplied pectate (now calcium pectate) to the wall and/or by additional Ca(2+) entering the wall structure. A tension-dependent cycle of pectate chemistry thus appeared to control growth while new wall was deposited as a consequence.

  11. [Modelling of pattern formation and oscillations in pH and transmembrane potential near the cell membrane of Chara corallina].

    PubMed

    Pliusnina, T Iu; Lavrova, A I; Riznichenko, G Iu; Rubin, A B

    2005-01-01

    A mathematical model of potencial-dependent proton transfer across the membrane of Chara corallina cells is considered. To construct the model, partial differential equations describing the system dynamics in time and in space were used. The variables of the model are the proton concentration and membrane potential. The model describes the experimentally observed inhomogeneous distribution of transmembrane potential and pH along the membrane and oscillations of the potential and pH in time. A mechanism of the distribution of pH and membrane potential along the Chara corallina cell is suggested.

  12. Simultaneous Measurements of Cytoplasmic K+ Concentration and the Plasma Membrane Electrical Parameters in Single Membrane Samples of Chara corallina

    PubMed Central

    Beilby, Mary J.; Blatt, Michael R.

    1986-01-01

    The electrophysiological properties of cytoplasm-rich fragments (single membrane samples) prepared from internodal cells of Chara corallina were explored in conjunction with K+-sensitive microelectrode and current-voltage (I-V) measurements. This system eliminated the problem of the inaccessible cytoplasmic layer, while preserving many of the electrical characteristics of the intact cells. In 0.1 millimolar external K concentration (Ko+), the resting conductance (membrane conductance Gm, 0.85 ± 0.25 Siemens per square meter (±standard error)) of the single membrane samples, was dominated by the proton pump, as suggested by the response of the near-linear I-V characteristic to changes in external pH. Initial cytoplasmic K+ activities (aK+), judged most reliable, gave values of 117 ± 67 millimolar; stable aK+ values were 77 ± 31 millimolar. Equilibrium potentials for K+ (Nernst equilibrium potential) (EK) calculated, using either of these data sets, were near the mean membrane potential (Vm). On a cell-to-cell basis, however, EK was generally negative of the Vm, despite an electrogenic contribution from the Chara proton pump. When Ko+ was increased to 1.0 millimolar or above, Gm rose (by 8- to 10-fold in 10 millimolar Ko+), the steady state I-V characteristics showed a region of negative slope conductance, and Vm followed EK. These results confirm previous studies which implicated a Ko+-induced and voltage-dependent permeability to K+ at the Chara plasma membrane. They provide an explanation for transitions between apparent Ko+-insensitive and Ko+-sensitive (`K+ electrode') behavior displayed by the membrane potential, as recorded in many algae and higher plant cells. PMID:16665044

  13. Electrophysiological characterization of the node in Chara corallina: functional differentiation for wounding response.

    PubMed

    Shimmen, Teruo

    2008-02-01

    Electrical characteristics of the node were analyzed in comparison with those of the flank of the internodal cell in Chara corallina. The dependence of the membrane potential of the node on pH and K+ concentration was almost the same as that of the flank. In the flank, the increase in the Ca2+ concentration stopped the depolarization in the presence of 100 mM KCl. In the node, however, Ca2+ could not stop the depolarization induced by 100 mM KCl. It has been reported that the node has a function to tranduce the signal of osmotic shock into a transient depolarization. In combination with osmotic shock, 10 mM K+ could induce a long-lasting depolarization of the node. These electrical characteristics of the node were suggested to be responsible for the electrical response to wounding in Characeae.

  14. Transduction of pressure signal to electrical signal upon sudden increase in turgor pressure in Chara corallina.

    PubMed

    Shimmen, Teruo; Ogata, Koreaki

    2013-05-01

    By taking advantage of large cell size of Chara corallina, we analyzed the membrane depolarization induced by decreased turgor pressure (Shimmen in J Plant Res 124:639-644, 2011). In the present study, the response to increased turgor pressure was analyzed. When internodes were incubated in media containing 200 mM dimethyl sulfoxide, their intracellular osmolality gradually increased and reached a steady level after about 3 h. Upon removal of dimethyl sulfoxide, turgor pressure quickly increased. In response to the increase in turgor pressure, the internodes generated a transient membrane depolarization at its nodal end. The refractory period was very long and it took about 2 h for full recovery after the depolarizing response. Involvement of protein synthesis in recovery from refractoriness was suggested, based on experiments using inhibitors.

  15. Voltage-Dependent K+-Channel in Protoplasmic Droplets of Chara corallina1

    PubMed Central

    Homblé, Fabrice; Ferrier, Jack M.; Dainty, Jack

    1987-01-01

    Passive transport of potassium through the plasma membrane of a protoplasmic droplet isolated from large internodal cells of Chara corallina Klein ex Willd., em, R.D.W. has been investigated using the patchclamp technique. When the membrane is hyperpolarized the conductance of a single K+-channel is of the order of magnitude of 100 picoSiemens and is reduced by tetraethylammonium chloride. Its open time is voltage dependent. This voltage-dependent K+-channel displays rectifying properties. The channel density is about 0.1 channel per square micrometer of membrane. When the membrane is depolarized the conductance of a single channel is of the order of magnitude of 30 picoSiemens and is insensitive to tetraethylammonium chloride. These results suggest that K+-channels are incorporated in the plasma membrane during membranogenesis of a protoplasmic droplet. They constitute further evidence for the existence of voltage-dependent K+-channels in plant cells. PMID:16665215

  16. FT-IR study of the Chara corallina cell wall under deformation.

    PubMed

    Toole, Geraldine A; Kacuráková, Marta; Smith, Andrew C; Waldron, Keith W; Wilson, Reginald H

    2004-02-25

    Fourier-transform infrared (FT-IR) microspectroscopy was used to investigate both the chemical composition of, and the effects of an applied strain on, the structure of the Chara corallina cell wall. The inner layers of the cell wall are known to have a transverse cellulose orientation with a gradient through the thickness to longitudinal orientation in the older layers. In both the native state and following the removal of various biopolymers by a sequential extraction infrared dichroism was used to examine the orientation of different biopolymers in cell-wall samples subjected to longitudinal strain. In the Chara system, cellulose microfibrils were found to be aligned predominantly transverse to the long axis of the cell and became orientated increasingly transversely as longitudinal strain increased. Simultaneously, the pectic polysaccharide matrix underwent molecular orientation parallel to the direction of strain. Following extraction in CDTA, microfibrils were orientated transversely to the strain direction, and again the degree of transverse orientation increased with increasing strain. However, the pectic polysaccharides of the matrix were not detected in the dichroic difference spectra. After a full sequential extraction, the cellulose microfibrils, now with greatly reduced crystallinity, were detected in a longitudinal direction and they became orientated increasingly parallel to the direction of strain as it increased.

  17. Identifying cytoplasmic input to the cell wall of growing Chara corallina.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2006-01-01

    Plants enlarge mostly because the walls of certain cells enlarge, with accompanying input of wall constituents and other factors from the cytoplasm. However, the enlargement can occur without input, suggesting an uncertain relationship between cytoplasmic input and plant growth. Therefore, the role of the input was investigated by quantitatively comparing growth in isolated walls (no input) with that in living cells (input occurring). Cell walls were isolated from growing internodes of Chara corallina and filled with pressurized oil to control turgor pressure while elongation was monitored. Turgor pressure in living cells was similarly controlled and monitored by adding/removing cell solution. Temperature was varied in some experiments. At all pressures and temperatures, isolated walls displayed turgor-driven growth indistinguishable in every respect from that in living cells, except the rate decelerated in the isolated walls while the living cells grew rapidly. The growth in the isolated walls was highly responsive to temperature, in contrast to the elastic extension that has been shown to be insensitive to similar temperatures. Consequently, strong intermolecular bonds were responsible for growth and weak bonds for elastic extension. Boiling the walls gave the same results, indicating that enzyme activities were not controlling these bonds. However, pectin added to isolated walls reversed their growth deceleration and returned the rate to that in the living cells. The pectin was similar to that normally produced by the cytoplasm and deposited in the wall, suggesting that continued cytoplasmic input of pectin may play a role in sustaining turgor-driven growth in Chara.

  18. Periplasm Turgor Pressure Controls Wall Deposition and Assembly in Growing Chara corallina Cells

    PubMed Central

    PROSEUS, TIMOTHY E.; BOYER, JOHN S.

    2006-01-01

    • Background and Aims New wall deposition usually accompanies plant growth. External osmotica inhibit both processes but wall precursors continue to be synthesized, and exocytosis follows. Consequently, the osmotica appear to act outside of the plasma membrane. Because this implies an action of turgor pressure (P) on the periplasm by unknown mechanisms, the following study was undertaken to determine whether P could act in a way that altered wall deposition and assembly in the periplasm while the cells grow. • Methods Cells of Chara corallina were exposed to P slightly below normal by using a pressure probe while supplying inorganic carbon in light. After labelling, the walls were isolated and the amount of new wall was determined. Similar measurements were made after treatment with osmotica. Chlortetracycline-stimulated exocytosis was determined microscopically. Polysaccharide properties were determined by confocal microscopy and vapour pressure osmometry in an ‘artificial periplasm’ in isolated Chara cell walls, using labelled dextran as an anologue of hemicellulose, and polygalacturonate as pectin. • Key Results Rapid growth and wall deposition occurred at normal P of 0.5 MPa but both processes decreased when P was lowered 0.1 MPa. Inorganic carbon uptake and exocytosis were unaffected. In the artificial periplasm, normal P caused high polysaccharide concentrations and rapid polysaccharide entry into the wall, and gel formation in the pectin. Lowering P decreased entry and gel formation. • Conclusions This is the first indication that normal P of 0.5 MPa can concentrate periplasmic polysaccharides sufficiently to cause cross-linking and gel formation in pectins while simultaneously fostering the entry of large polysaccharides into small interstices in the existing wall. This P-action would thicken the primary wall and form a smooth transition between the new and old structure, suggesting a molecular mechanism of wall deposition and assembly while the

  19. Recombinant motor domain constructs of Chara corallina myosin display fast motility and high ATPase activity.

    PubMed

    Ito, Kohji; Kashiyama, Taku; Shimada, Kiyo; Yamaguchi, Akira; Awata, Jun ya; Hachikubo, You; Manstein, Dietmar J; Yamamoto, Keiichi

    2003-12-26

    The mechanism and structural features that are responsible for the fast motility of Chara corallina myosin (CCM) have not been elucidated, so far. The low yields of native CCM that can be purified to homogeneity were the major reason for this. Here, we describe the expression of recombinant CCM motor domains, which support the fast movement of actin filaments in an in vitro motility assay. A CCM motor domain without light chain binding site moved actin filaments at a velocity of 8.8 microm/s at 30 degrees C and a CCM motor domain with an artificial lever arm consisting of two alpha-actinin repeats moved actin filaments at 16.2 microm/s. Both constructs displayed high actin-activated ATPase activities ( approximately 500 Pi/s/head), which is indicative of a very fast hydrolysis step. Our results provide an excellent system to dissect the specific structural and functional features that distinguish the myosin responsible for fast cytoplasmic streaming.

  20. Turgor Pressure Moves Polysaccharides into Growing Cell Walls of Chara corallina

    PubMed Central

    PROSEUS, TIMOTHY E.; BOYER, JOHN S.

    2005-01-01

    • Background and Aims Plant growth involves pressure-driven cell enlargement generally accompanied by deposition of new cell wall. New polysaccharides are secreted by the plasma membrane but their subsequent entry into the wall is obscure. Therefore, polysaccharides and gold colloids of various sizes were presented to the inner wall face as though they were secreted by the plasma membrane. • Methods Primary cell walls were isolated from growing internodes of Chara corallina and one end was attached to a glass capillary. Solutions of dextran or suspensions of gold colloids were pushed into the lumen by oil in the capillary. The oil did not enter the wall, and the solution or suspension was pressed against the inner wall face, pressurized at various ‘artificial’ P (turgor pressure), and polymer or colloid movement through the wall was monitored. • Key Results Interstices in the wall matrix had a diameter of about 4·6 nm measured at high P with gold colloids. Small solute (0·8 nm) readily moved through these interstices unaffected by P. Dextrans of 3·5 nm diameter moved faster at higher P while dextran of 9 nm scarcely entered unless high P was present. Dextran of 11 nm did not enter unless P was above a threshold, and dextran of 27 nm did not enter at P as high as 0·5 MPa. The walls filtered the dextrans, which became concentrated against the inner wall face, and most polymer movement occurred after P stabilized and bulk flow ended. • Conclusions P created a steep gradient in concentration and mechanical force at the inner wall face that moved large polymers into small wall openings apparently by starting a polymer end or deforming the polymer mechanically at the inner wall face. This movement occurred at P generally accepted to extend the walls for growth. PMID:15760911

  1. Effects of lanthanum on calcium and magnesium contents and cytoplasmic streaming of internodal cells of Chara corallina.

    PubMed

    Li, Zijie; Zhang, Zhiyong; Yu, Ming; Zhou, Yunlong; Zhao, Yuliang

    2011-10-01

    Biological and environmental effects of lanthanide series of elements have received much attention recently due to their wide applications. In this study, effects of La(3+) treatments on calcium and magnesium concentrations as well as cytoplasmic streaming of internodal cells of Chara corallina were investigated. At all treatment concentrations (10, 100, and 1,000 μM), La(3+) significantly decreased calcium concentrations in the cell-wall fractions after 5-h treatments. Calcium concentrations in the cell contents and magnesium concentrations in the cell-wall fractions were reduced by 100 and 1,000 μM La(3+) treatments. However, cytoplasmic streaming as an indicator of [Ca(2+)](cyt) was only inhibited at the highest La(3+) concentration (1,000 μM). The results suggest that La(3+) may affect cellular calcium homeostasis by actions other than as a simple Ca(2+) antagonist. La(3+) could partially compensate for calcium deficiency at certain concentrations.

  2. Involvement of protein synthesis in recovery from refractory period of electrical depolarization induced by osmotic stimulation in Chara corallina.

    PubMed

    Shimmen, Teruo

    2011-09-01

    Upon addition of sorbitol to the external medium of an internodal cell of Chara corallina, a transient depolarization is induced at its nodal end (Shimmen in Plant Cell Physiol 44:1215-1224, 2003). In the present study, refractory period was found to be very long, 2-4 h. Recovery from refractoriness was completely inhibited by inhibitors of eukaryote-type protein synthesis, cycloheximide or anisomysin, but not by inhibitors of prokaryote-type protein synthesis. This suggested that proteinous factor(s) responsible for generation of the depolarization is lost or inactivated upon depolarization and synthesized during the resting state. Low temperature, which is supposed to inhibit protein synthesis, also inhibited recovery from refractoriness. When unstimulated internodal cells were incubated in the medium containing an inhibitor of eukaryote-type protein synthesis, generation of the depolarization was almost completely inhibited. This result suggested that the factor is slowly turning over even in the absence of osmotic stimulation.

  3. Studies on alkaline band formation in Chara corallina: ameliorating effect of Ca2+ on inhibition induced by osmotic shock.

    PubMed

    Shimmen, Teruo; Yonemura, Satoko; Negoro, Mio; Lucas, William J

    2003-09-01

    Although the decrease in cell turgor by application of sorbitol to the external medium did not inhibit the alkaline band formation in Chara corallina, recovery of normal turgor severely inhibited it. Alkaline-loading analysis suggested that the inhibition of alkaline band formation was caused by inhibition of HCO(3)(-) influx but not that of OH(-) efflux. In the presence of 10 mM CaCl(2), the capacity of alkaline band formation was maintained during osmotic treatment. Cells could not form alkaline bands, when plasmolysis was induced by application of sorbitol at a higher concentration. Addition of 10 mM CaCl(2) could ameliorate the inhibition caused by plasmolyis.

  4. Intracellular axial current in Chara corallina reflects the altered kinetics of ions in cytoplasm under the influence of light.

    PubMed

    Baudenbacher, F; Fong, L E; Thiel, G; Wacke, M; Jazbinsek, V; Holzer, J R; Stampfl, A; Trontelj, Z

    2005-01-01

    Recent experiments demonstrate that the concentration of Ca2+ in cytoplasm of Chara corallina internodal cells plays important role in electrical excitation of the plasma membrane. The concentration of free Ca2+ in the cytoplasm -[Ca2+]c is also sensitive to visible light. Both phenomena were simultaneously studied by noninvasive measuring action potential (AP) and magnetic field with a superconducting quantum interference device magnetometer in very close vicinity of electrically excited internodal C. corallina cells. A temporal shift in the depolarization maximum, which progressively occurred after transferring cells from the dark into the light, can be explained by the extended Othmer model. Assuming that the change in membrane voltage during the depolarization part of AP is the direct consequence of an activation of [Ca2+]c sensitive Cl- channels, the model simulations compare well with the experimental data. We can say that we have an example of electrically elicited AP that is of biochemical nature. Electric and magnetic measurements are in good agreement.

  5. Calcium pectate chemistry causes growth to be stored in Chara corallina: a test of the pectate cycle.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2008-08-01

    Calcium pectate chemistry was reported to control the growth rate of cells of Chara corallina, and required turgor pressure (P) to do so. Accordingly, this chemistry should account for other aspects of growth, particularly the ability of plants to compensate for brief exposure to low P, that is, to 'store' growth. Live Chara cells or isolated walls were attached to a pressure probe, and P was varied. Low P caused growth to be inhibited in live cells, but when P returned to normal (0.5 MPa), a flush of growth completely compensated for that lost at low P for as long as 23-53 min. This growth storage was absent in isolated walls, mature cells and live cells exposed to cold, indicating that the cytoplasm delivered a metabolically derived growth factor needing P for its action. Because the cytoplasm delivered pectate needing P for its action, pectate was supplied to isolated walls at low P as though the cytoplasm had done so. Growth was stored while otherwise none occurred. It was concluded that a P-dependent cycle of calcium pectate chemistry not only controlled growth rate and new wall deposition, but also accounted for stored growth.

  6. Insight into the mechanism of fast movement of myosin from Chara corallina.

    PubMed

    Sumiyoshi, Hiroki; Ooguchi, Masami; Ooi, Atsushi; Okagaki, Tsuyoshi; Higashi-Fujime, Sugie

    2007-02-01

    Chara myosin, two-headed plant myosin belonging to class XI, slides F-actin at maximally 60 microm s(-1). To elucidate the mechanism of this fast sliding, we extensively investigated its mechanochemical properties. The maximum actin activated ATPase activity, Vmax, was 21.3 s(-1) head(-1) in a solution, but when myosin was immobilized on the surface, its activity was 57.6 s(-1) head(-1) at 2 mg ml(-1) of F-actin. The sliding velocity and the actin activated ATPase activity were greatly inhibited by ADP, suggesting that ADP dissociation was the rate limiting step. With the extensive assay of motility by varying the surface density, the duty ratio of Chara myosin was found to be 0.49-0.44 from velocity measurements and 0.34 from the landing rate analysis. At the surface density of 10 molecules microm(-2), Chara myosin exhibited pivot movement under physiological conditions. Based on the results obtained, we will discuss the sliding mechanism of Chara myosin according to the working stroke model in terms of its physiological aspects. aspects.

  7. Investigation of the effects of continuous-wave, pulse- and amplitude-modulated microwaves on single excitable cells of Chara corallina.

    PubMed

    Liu, L M; Garber, F; Cleary, S F

    1982-01-01

    Single internodal excitable cells of Chara corallina were exposed to CW, pulse-modulated and sinusoidally modulated S-band microwave fields in a temperature-controlled waveguide exposure chamber. All electrical measurements were made external to the waveguide (ie, under no impressed microwave field). The dependent variables measured before, during, and after exposure to the S-band microwave fields included: resting potential, amplitude of the action potential, rise and decay time of the action potential, conduction velocity, and excitability. Cells maintained at 22 +/- 0.1 degrees C during exposure showed no consistent or statistically significant microwave-dependent alterations in any of the dependent variables.

  8. Cyclosis-related asymmetry of chloroplast-plasma membrane interactions at the margins of illuminated area in Chara corallina cells.

    PubMed

    Dodonova, Svetlana O; Bulychev, Alexander A

    2011-10-01

    Cytoplasmic streaming in plant cells is an effective means of intracellular transport. The cycling of ions and metabolites between the cytosol and chloroplasts in illuminated cell regions may alter the cytoplasm composition, while directional flow of this modified cytoplasm may affect the plasma membrane and chloroplast activities in cell regions residing downstream of the illumination area. The impact of local illumination is predicted to be asymmetric because the cell regions located downstream and upstream in the cytoplasmic flow with respect to illumination area would be exposed to flowing cytoplasm whose solute composition was influenced by photosynthetic or dark metabolism. This hypothesis was checked by measuring H(+)-transporting activity of plasmalemma and chlorophyll fluorescence of chloroplasts in shaded regions of Chara corallina internodal cells near opposite borders of illuminated region (white light, beam width 2 mm). Both the apoplastic pH and chlorophyll fluorescence, recorded in shade regions at equal distances from illuminated area, exhibited asymmetric light-on responses depending on orientation of cytoplasmic streaming at the light-shade boundary. In the region where the cytoplasm flowed from illuminated area to the measurement area, the alkaline zone (a zone with high plasma membrane conductance) was formed within 4-min illumination, whereas no alkaline zone was observed in the area where cytoplasm approached the boundary from darkened regions. The results emphasize significance of cyclosis in lateral distribution of a functionally active intermediate capable of affecting the membrane transport across the plasmalemma, the functional activity of chloroplasts, and pattern formation in the plant cell.

  9. Extracting and purifying R-phycoerythrin from Mediterranean red algae Corallina elongata Ellis & Solander.

    PubMed

    Rossano, R; Ungaro, N; D'Ambrosio, A; Liuzzi, G M; Riccio, P

    2003-03-20

    R-Phycoerythrin (R-PE) is a protein acting as a photosynthetic accessory pigment in red algae (Rodophyta). This protein has gained importance in many biotechnological applications in food science, immunodiagnostic, therapy, cosmetics, protein and cell labelling, and analytical processes. In this paper we report on a new, one step procedure for the extraction and purification of R-PE from a new source: the Mediterranean red algae Corallina elongata Ellis & Solander. This red algae contains mainly R-PE and is suitable for the production in culture. No other contaminating phycobiliproteins could be detected in the extracts. The method we propose for the purification is based on the use of hydroxyapatite, a chromatographic resin that can be produced in the laboratory at very low cost and can be used batch-wise with large amounts of extracts, alternative to chromatography, and therefore can be scaled up. Both the yield and the purity of R-PE are very good.

  10. A re-examination of the minor role of unstirred layers during the measurement of transport coefficients of Chara corallina internodes with the cell pressure probe.

    PubMed

    Ye, Qing; Kim, Yangmin; Steudle, Ernst

    2006-05-01

    The impact of unstirred layers (USLs) during cell pressure probe experiments with Chara corallina internodes has been quantified. The results show that the hydraulic conductivity (Lp) measured in hydrostatic relaxations was not significantly affected by USLs even in the presence of high water flow intensities ('sweep-away effect'). During pressure clamp, there was a reversible reduction in Lp by 20%, which was explained by the constriction of water to aquaporins (AQPs) in the C. corallina membrane and a rapid diffusional equilibration of solutes in arrays where water protruded across AQPs. In osmotic experiments, Lp, and permeability (Ps) and reflection (sigma s) coefficients increased as external flow rate of medium increased, indicating some effects of external USLs. However, the effect was levelling off at 'usual' flow rates of 0.20-0.30 m s(-1) and in the presence of vigorous stirring by air bubbles, suggesting a maximum thickness of external USLs of around 30 microm including the cell wall. Because the diameters of internodes were around 1 mm, internal USLs could have played a significant or even a dominating role, at least in the presence of the rapidly permeating solutes used [acetone, 2-propanol and dimethylformamide (DMF)]. A comparison of calculated (diffusion kinetics) and of measured permeabilities indicated an upper limit of the contribution of USLs for the rapidly moving solute acetone of 29%, and of 15% for the less rapidly permeating DME The results throw some doubt on recent claims that in C. corallina, USLs rather than the cell membrane dominate solute uptake, at least for the most rapidly moving solute acetone.

  11. Control of Cl− Efflux in Chara corallina by Cytosolic pH, Free Ca2+, and Phosphorylation Indicates a Role of Plasma Membrane Anion Channels in Cytosolic pH Regulation1

    PubMed Central

    Johannes, Eva; Crofts, Alan; Sanders, Dale

    1998-01-01

    Enhanced Cl− efflux during acidosis in plants is thought to play a role in cytosolic pH (pHc) homeostasis by short-circuiting the current produced by the electrogenic H+ pump, thereby facilitating enhanced H+ efflux from the cytosol. Using an intracellular perfusion technique, which enables experimental control of medium composition at the cytosolic surface of the plasma membrane of charophyte algae (Chara corallina), we show that lowered pHc activates Cl− efflux via two mechanisms. The first is a direct effect of pHc on Cl− efflux; the second mechanism comprises a pHc-induced increase in affinity for cytosolic free Ca2+ ([Ca2+]c), which also activates Cl− efflux. Cl− efflux was controlled by phosphorylation/dephosphorylation events, which override the responses to both pHc and [Ca2+]c. Whereas phosphorylation (perfusion with the catalytic subunit of protein kinase A in the presence of ATP) resulted in a complete inhibition of Cl− efflux, dephosphorylation (perfusion with alkaline phosphatase) arrested Cl− efflux at 60% of the maximal level in a manner that was both pHc and [Ca2+]c independent. These findings imply that plasma membrane anion channels play a central role in pHc regulation in plants, in addition to their established roles in turgor/volume regulation and signal transduction. PMID:9733536

  12. Spatio-temporal patterns of photosystem II activity and plasma-membrane proton flows in Chara corallina cells exposed to overall and local illumination.

    PubMed

    Bulychev, Alexander; Vredenberg, Wim

    2003-11-01

    Pulse-amplitude modulated microfluorometry and an extracellular pH microprobe were used to examine light-induced spatial heterogeneity of photosynthetic and H(+)-transporting activities in cells of Chara corallina Klein ex Willd. Subcellular domains featuring different PSII photochemical activities were found to conform to alternate alkaline and acid zones produced near the cell surface, with peaks of PSII activity correlating with the position of acid zones. Buffers eliminated pH variations near the cell surface but did not destroy the variations in PSII photochemical yield (deltaF/Fm'). When a dark-adapted cell was exposed to actinic light, the PSII effective yield decreased within 5-15 min in the alkaline regions but rose after the initial decline in the acid regions. The light-induced decrease in deltaF/Fm' in the alkaline regions occurred prior to or synchronously with the steep rise in local pH. The kinetics of deltaF/Fm', Fm', and F observed in alkaline regions under overall illumination of Chara cells were replaced by those typical of acid regions, when the illumination area size was restricted to 1.5-2 mm. The data show that photoinduced patterns in photosynthetic activity are not predetermined by the particular structural organization of alkaline and acid cell regions but are subject to dynamic changes.

  13. Osmoregulation or turgor regulation in chara?

    PubMed

    Bisson, M A; Bartholomew, D

    1984-02-01

    Chara corallina Klein ex Willd. wm. R.D.W. (= C. australis R. Br.), a fresh water alga, maintains a constant internal osmotic pressure when external osmotic pressure is increased. This results in a decrease in turgor pressure. Chara osmoregulates effectively in the presence of high CaCl(2) and raffinose, but is less efficient in response to increased NaCl. Decreasing external pH from 7 to 5 results in a decrease in turgor, but increasing it to values as high as 9 has no effect. Increasing the daily amount of light from 0.5 to 24 hours has no effect on turgor.

  14. Characterising the microbiome of Corallina officinalis, a dominant calcified intertidal red alga.

    PubMed

    Brodie, Juliet; Williamson, Christopher; Barker, Gary L; Walker, Rachel H; Briscoe, Andrew; Yallop, Marian

    2016-08-01

    The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome. Unclassified sequences made up 25% of sequences, suggesting insufficient sampling of the world's oceans/macroalgae. The greatest diversity in the microbiome was on the upper shore, followed by the lower shore then the middle shore, although the microbiome community composition did not vary between shore levels. The C. officinalis core microbiome was broadly similar in composition to those reported in the literature for crustose coralline algae (CCAs) and free-living rhodoliths. Differences in relative abundance of the phyla between the different types of calcified macroalgal species may relate to the intertidal versus subtidal habit of the taxa and functionality of the microbiome components. The results indicate that much work is needed to identify prokaryotic taxa, and to determine the nature of the relationship of the bacteria with the calcified host spatially, temporally and functionally. PMID:27222222

  15. Characterising the microbiome of Corallina officinalis, a dominant calcified intertidal red alga.

    PubMed

    Brodie, Juliet; Williamson, Christopher; Barker, Gary L; Walker, Rachel H; Briscoe, Andrew; Yallop, Marian

    2016-08-01

    The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome. Unclassified sequences made up 25% of sequences, suggesting insufficient sampling of the world's oceans/macroalgae. The greatest diversity in the microbiome was on the upper shore, followed by the lower shore then the middle shore, although the microbiome community composition did not vary between shore levels. The C. officinalis core microbiome was broadly similar in composition to those reported in the literature for crustose coralline algae (CCAs) and free-living rhodoliths. Differences in relative abundance of the phyla between the different types of calcified macroalgal species may relate to the intertidal versus subtidal habit of the taxa and functionality of the microbiome components. The results indicate that much work is needed to identify prokaryotic taxa, and to determine the nature of the relationship of the bacteria with the calcified host spatially, temporally and functionally.

  16. Excitation-induced dynamics of external pH pattern in Chara corallina cells and its dependence on external calcium concentration.

    PubMed

    Eremin, Alexey; Bulychev, Alexander; Krupenina, Natalia A; Mair, Thomas; Hauser, Marcus J B; Stannarius, Ralf; Müller, Stefan C; Rubin, Andrei B

    2007-01-01

    The influence of cell excitation and external calcium level on the dynamics of light-induced pH bands along the length of Chara corallina cells is studied in the present paper. Generation of an action potential (AP) transiently quenched these pH patterns, which was more pronounced at 0.05-0.1 mM Ca2+ than at higher concentrations of Ca2+ (0.6-2 mM) in the medium. After transient smoothing of the pH bands, some alkaline peaks reemerged at slightly shifted positions in media with low Ca2+ concentrations, while at high Ca2+ concentrations, the alkaline spots reappeared exactly at their initial positions. This Ca2+ dependency has been revealed by both digital imaging and pH microelectrodes. The stabilizing effect of external Ca2+ on the locations of recovering alkaline peaks is supposedly due to formation of a physically heterogeneous environment around the cell owing to precipitation of CaCO3 in the alkaline zones at high Ca2+ during illumination. The elevation of local pH by dissolving CaCO3 facilitates the reappearance of alkaline spots at their initial locations after temporal suppression caused by cell excitation. At low Ca2+ concentrations, when the solubility product of CaCO3 is not attained, the alkaline peaks are not stabilized by CaCO3 dissolution and may appear at random locations.

  17. The effect of the external medium on the gravity-induced polarity of cytoplasmic streaming in Chara corallina (Characeae)

    NASA Technical Reports Server (NTRS)

    Staves, M. P.; Wayne, R.; Leopold, A. C.

    1997-01-01

    Gravity induces a polarity of cytoplasmic streaming in vertical internodal cells of Chara such that the downwardly directed stream moves faster than the upwardly directed stream. In order to determine whether the statolith theory (in which intracellular sedimenting particles are responsible for gravity sensing) or the gravitational pressure theory (in which the entire protoplast acts as the gravity sensor) best explain the gravity response in Chara internodal cells, we controlled the physical properties of the external medium, including density and osmolarity, with impermeant solutes and examined the effect on the polarity of cytoplasmic streaming. As the density of the external medium is increased, the polarity of cytoplasmic streaming decreases and finally disappears when the density of the external medium is equal to that of the cell (1015 kg/m3). A further increase in the density of the external medium causes a reversal of the gravity response. These results are consistent with the gravitational pressure theory of gravity sensing since the buoyancy of the protoplast is dependent on the difference between the density of the protoplast and the external medium, and are inconsistent with the statolith theory since the buoyancy of intracellular particles are unaffected by changes in the external medium.

  18. Enzyme-Less Growth in Chara and Terrestrial Plants.

    PubMed

    Boyer, John S

    2016-01-01

    Enzyme-less chemistry appears to control the growth rate of the green alga Chara corallina. The chemistry occurs in the wall where a calcium pectate cycle determines both the rate of wall enlargement and the rate of pectate deposition into the wall. The process is the first to indicate that a wall polymer can control how a plant cell enlarges after exocytosis releases the polymer to the wall. This raises the question of whether other species use a similar mechanism. Chara is one of the closest relatives of the progenitors of terrestrial plants and during the course of evolution, new wall features evolved while pectate remained one of the most conserved components. In addition, charophytes contain auxin which affects Chara in ways resembling its action in terrestrial plants. Therefore, this review considers whether more recently acquired wall features require different mechanisms to explain cell expansion. PMID:27446106

  19. Enzyme-Less Growth in Chara and Terrestrial Plants

    PubMed Central

    Boyer, John S.

    2016-01-01

    Enzyme-less chemistry appears to control the growth rate of the green alga Chara corallina. The chemistry occurs in the wall where a calcium pectate cycle determines both the rate of wall enlargement and the rate of pectate deposition into the wall. The process is the first to indicate that a wall polymer can control how a plant cell enlarges after exocytosis releases the polymer to the wall. This raises the question of whether other species use a similar mechanism. Chara is one of the closest relatives of the progenitors of terrestrial plants and during the course of evolution, new wall features evolved while pectate remained one of the most conserved components. In addition, charophytes contain auxin which affects Chara in ways resembling its action in terrestrial plants. Therefore, this review considers whether more recently acquired wall features require different mechanisms to explain cell expansion. PMID:27446106

  20. Anti-photoaging activity and inhibition of matrix metalloproteinase (MMP) by marine red alga, Corallina pilulifera methanol extract

    NASA Astrophysics Data System (ADS)

    Ryu, BoMi; Qian, Zhong-Ji; Kim, Moon-Moo; Nam, Ki Wan; Kim, Se-Kwon

    2009-02-01

    Matrix metalloproteinases (MMPs), a key component in photoaging of the skin due to exposure to ultraviolet A, appear to be increased by UV-irradiation-associated generation of reactive oxygen species (ROS). In this study, the alga Corallina pilulifera methanol (CPM) extract has been shown to exert a potent antioxidant activity and protective effect on UVA-induced oxidative stress of human dermal fibroblast (HDF) cell. Antioxidant evaluated by various antioxidant assays. These include reducing power, total antioxidant, DPPH radical scavenging, hydroxyl radical scavenging and protective effect on DNA damage caused by hydroxyl radicals generated. Further, the ROS level was detected using a fluorescence probe, 2',7'-dichlorofluorescein diacetate (DCFH-DA), which could be converted to highly fluorescent dichlorofluorescein (DCF) with the presence of intracellular ROS on HT-1080 cells. Those various antioxidant activities were compared to standard antioxidants such as α-tocopherol. In addition, the in vitro activities of MMP-2 and MMP-9 in HDF cell were inhibited by C. pilulifera methanol extract dose dependently by using gelatin zymography method. The results obtained in the present study suggested that the C. pilulifera methanol extract may be a potential source of natural anti-photoaging.

  1. Metabolomics of a single vacuole reveals metabolic dynamism in an alga Chara australis.

    PubMed

    Oikawa, Akira; Matsuda, Fumio; Kikuyama, Munehiro; Mimura, Tetsuro; Saito, Kazuki

    2011-10-01

    Metabolomics is the most reliable analytical method for understanding metabolic diversity in single organelles derived from single cells. Although metabolites such as phosphate compounds are believed to be localized in different organelles in a highly specific manner, the process of metabolite compartmentalization in the cell is not thoroughly understood. The analysis of metabolites in single organelles has consequently presented a significant challenge. In this study, we used a metabolomic method to elucidate the localization and dynamics of 125 known metabolites isolated from the vacuole and cytoplasm of a single cell of the alga Chara australis. The amount of metabolites in the vacuole and the cytoplasm fluctuated asynchronously under various stress conditions, suggesting that metabolites are spatially regulated within the cell. Metabolite transport across the vacuolar membrane can be directly detected using the microinjection technique, which may reveal a previously unknown function of the vacuole.

  2. Etoposide interferes with the process of chromatin condensation during alga Chara vulgaris spermiogenesis.

    PubMed

    Agnieszka, Wojtczak

    2014-10-01

    DNA topoisomerase II plays an essential role in animal spermiogenesis, where changes of chromatin structure are connected with appearance of transient DNA breaks. Such topo II activity can be curtailed by inhibitors such as etoposide and suramine. The aim of the present study was to investigate, for the first time, the effect of etoposide on spermatid chromatin remodeling in the green alga Chara vulgaris. This inhibitor prolonged the early spermiogenesis stages and blocked the formation of the phosphorylated form of histone H2AX at stages VI-VII. The lack of transient DSBs at these stages impairs the elimination of supercoils containing nucleosomes which lead to disturbances in nucleoprotein exchange and the pattern of spermatid chromatin fibrils at stages VI-VIII. Immunofluorescent and ultrastructural observations revealed that during C. vulgaris spermiogenesis topo II played an important role similar to that in mammals. Some corresponding features had been pointed out before, the present studies showed further similarities. PMID:25041830

  3. Etoposide interferes with the process of chromatin condensation during alga Chara vulgaris spermiogenesis.

    PubMed

    Agnieszka, Wojtczak

    2014-10-01

    DNA topoisomerase II plays an essential role in animal spermiogenesis, where changes of chromatin structure are connected with appearance of transient DNA breaks. Such topo II activity can be curtailed by inhibitors such as etoposide and suramine. The aim of the present study was to investigate, for the first time, the effect of etoposide on spermatid chromatin remodeling in the green alga Chara vulgaris. This inhibitor prolonged the early spermiogenesis stages and blocked the formation of the phosphorylated form of histone H2AX at stages VI-VII. The lack of transient DSBs at these stages impairs the elimination of supercoils containing nucleosomes which lead to disturbances in nucleoprotein exchange and the pattern of spermatid chromatin fibrils at stages VI-VIII. Immunofluorescent and ultrastructural observations revealed that during C. vulgaris spermiogenesis topo II played an important role similar to that in mammals. Some corresponding features had been pointed out before, the present studies showed further similarities.

  4. Two Class I Aldolases in the Green Alga Chara foetida (Charophyceae) 1

    PubMed Central

    Jacobshagen, Sigrid; Schnarrenberger, Claus

    1988-01-01

    Aldolase activity of Chara foetida (Braun) could be separated into a minor (peak I) and a major peak (peak II) by ion-exchange chromatography on DEAE-cellulose. Affinity chromatography on P-cellulose resulted in highly purified aldolase preparations with specific activities of 3.2 and 4.8 units per milligram protein and molecular subunit masses of 37 and 35 kilodalton, as shown by SDS-PAGE, for the aldolase of peak I and peak II, respectively. Both aldolases belong to class I aldolase since the activity is not inhibited by 1 millimolar EDTA. The Km (fructose-1,6-bisphosphate) values were 0.64 and 13.4 micromolar, respectively. The aldolase of peak I showed a 6.7 times stronger crossreaction with a specific antiserum against the cytosol aldolase of spinach than with an antiserum against the chloroplast aldolase of spinach. On the other hand the aldolase of peak II showed a 5.1 times stronger cross-reaction with the α-plastidaldolase antiserum than with the α-cytosol-aldolase antiserum. For algae this is the first separation of two class I aldolases. They are similar to the cytosol and chloroplast aldolases in higher plants, but different from a reported class I (Me2+ independent) and class II (Me2+ dependent) aldolase in other algae. Images Fig. 2 PMID:16666130

  5. Two Class I Aldolases in the Green Alga Chara foetida (Charophyceae).

    PubMed

    Jacobshagen, S; Schnarrenberger, C

    1988-05-01

    Aldolase activity of Chara foetida (Braun) could be separated into a minor (peak I) and a major peak (peak II) by ion-exchange chromatography on DEAE-cellulose. Affinity chromatography on P-cellulose resulted in highly purified aldolase preparations with specific activities of 3.2 and 4.8 units per milligram protein and molecular subunit masses of 37 and 35 kilodalton, as shown by SDS-PAGE, for the aldolase of peak I and peak II, respectively. Both aldolases belong to class I aldolase since the activity is not inhibited by 1 millimolar EDTA. The K(m) (fructose-1,6-bisphosphate) values were 0.64 and 13.4 micromolar, respectively. The aldolase of peak I showed a 6.7 times stronger crossreaction with a specific antiserum against the cytosol aldolase of spinach than with an antiserum against the chloroplast aldolase of spinach. On the other hand the aldolase of peak II showed a 5.1 times stronger cross-reaction with the alpha-plastidaldolase antiserum than with the alpha-cytosol-aldolase antiserum. For algae this is the first separation of two class I aldolases. They are similar to the cytosol and chloroplast aldolases in higher plants, but different from a reported class I (Me(2+) independent) and class II (Me(2+) dependent) aldolase in other algae.

  6. Convoluted Plasma Membrane Domains in the Green Alga Chara are Depleted of Microtubules and Actin Filaments.

    PubMed

    Sommer, Aniela; Hoeftberger, Margit; Hoepflinger, Marion C; Schmalbrock, Sarah; Bulychev, Alexander; Foissner, Ilse

    2015-10-01

    Charasomes are convoluted plasma membrane domains in the green alga Chara australis. They harbor H(+)-ATPases involved in acidification of the medium, which facilitates carbon uptake required for photosynthesis. In this study we investigated the distribution of cortical microtubules and cortical actin filaments in relation to the distribution of charasomes. We found that microtubules and actin filaments were largely lacking beneath the charasomes, suggesting the absence of nucleating and/or anchoring complexes or an inhibitory effect on polymerization. We also investigated the influence of cytoskeleton inhibitors on the light-dependent growth and the darkness-induced degradation of charasomes. Inhibition of cytoplasmic streaming by cytochalasin D significantly inhibited charasome growth and delayed charasome degradation, whereas depolymerization of microtubules by oryzalin or stabilization of microtubules by paclitaxel had no effect. Our data indicate that the membrane at the cytoplasmic surface of charasomes has different properties in comparison with the smooth plasma membrane. We show further that the actin cytoskeleton is necessary for charasome growth and facilitates charasome degradation presumably via trafficking of secretory and endocytic vesicles, respectively. However, microtubules are required neither for charasome growth nor for charasome degradation. PMID:26272553

  7. Convoluted Plasma Membrane Domains in the Green Alga Chara are Depleted of Microtubules and Actin Filaments.

    PubMed

    Sommer, Aniela; Hoeftberger, Margit; Hoepflinger, Marion C; Schmalbrock, Sarah; Bulychev, Alexander; Foissner, Ilse

    2015-10-01

    Charasomes are convoluted plasma membrane domains in the green alga Chara australis. They harbor H(+)-ATPases involved in acidification of the medium, which facilitates carbon uptake required for photosynthesis. In this study we investigated the distribution of cortical microtubules and cortical actin filaments in relation to the distribution of charasomes. We found that microtubules and actin filaments were largely lacking beneath the charasomes, suggesting the absence of nucleating and/or anchoring complexes or an inhibitory effect on polymerization. We also investigated the influence of cytoskeleton inhibitors on the light-dependent growth and the darkness-induced degradation of charasomes. Inhibition of cytoplasmic streaming by cytochalasin D significantly inhibited charasome growth and delayed charasome degradation, whereas depolymerization of microtubules by oryzalin or stabilization of microtubules by paclitaxel had no effect. Our data indicate that the membrane at the cytoplasmic surface of charasomes has different properties in comparison with the smooth plasma membrane. We show further that the actin cytoskeleton is necessary for charasome growth and facilitates charasome degradation presumably via trafficking of secretory and endocytic vesicles, respectively. However, microtubules are required neither for charasome growth nor for charasome degradation.

  8. Convoluted Plasma Membrane Domains in the Green Alga Chara are Depleted of Microtubules and Actin Filaments

    PubMed Central

    Sommer, Aniela; Hoeftberger, Margit; Hoepflinger, Marion C.; Schmalbrock, Sarah; Bulychev, Alexander; Foissner, Ilse

    2015-01-01

    Charasomes are convoluted plasma membrane domains in the green alga Chara australis. They harbor H+-ATPases involved in acidification of the medium, which facilitates carbon uptake required for photosynthesis. In this study we investigated the distribution of cortical microtubules and cortical actin filaments in relation to the distribution of charasomes. We found that microtubules and actin filaments were largely lacking beneath the charasomes, suggesting the absence of nucleating and/or anchoring complexes or an inhibitory effect on polymerization. We also investigated the influence of cytoskeleton inhibitors on the light-dependent growth and the darkness-induced degradation of charasomes. Inhibition of cytoplasmic streaming by cytochalasin D significantly inhibited charasome growth and delayed charasome degradation, whereas depolymerization of microtubules by oryzalin or stabilization of microtubules by paclitaxel had no effect. Our data indicate that the membrane at the cytoplasmic surface of charasomes has different properties in comparison with the smooth plasma membrane. We show further that the actin cytoskeleton is necessary for charasome growth and facilitates charasome degradation presumably via trafficking of secretory and endocytic vesicles, respectively. However, microtubules are required neither for charasome growth nor for charasome degradation. PMID:26272553

  9. Mitochondrial sequestration of BCECF after ester loading in the giant alga Chara australis.

    PubMed

    Blatt, M R; Beilby, M J

    2007-01-01

    Ratiometric fluorescent dyes are often used to monitor free ion concentrations in vivo, especially in cells that are recalcitrant to transformation with genetically encoded fluorescent markers. Although intracellular dye distributions are often found to be cytosolic, dye localisation has often not been examined in detail. We began exploring the use of BCECF (2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein) to monitor pH in the giant alga Chara australis and discovered that younger leaf cells could be loaded using the acetoxymethyl ester of BCECF. However, we were puzzled to find in microphotometric measurements that the fluorescence ratio appeared insensitive to manipulations affecting cytosolic pH. Confocal imaging of C. australis cells loaded with BCECF showed an accumulation of the dye in two locations: (1) on the outside of the chloroplasts in irregularly shaped stationary bodies; (2) within 1-1.5 mum structures that moved rapidly with the pericellular cytoplasmic streaming. Together with the streaming cytoplasm, these organelles were rendered stationary with 50 muM cytochalasin D. Rhodamine 123, a mitochondrionspecific dye, highlighted organelles outside of the chloroplasts, similar to those shown by BCECF in location 1. We conclude that in the cytoplasmic compartment, BCECF was sequestered within cytoplasmic mitochondria in immature and fast-growing cells and within the cortical mitochondrial system in older and slowly growing cells. Thus, BCECF-AM is unsuitable for reporting changes in cytosolic pH in C. australis but might be employed in future to study pH changes in the mitochondria.

  10. Calcite encrustation in macro-algae Chara and its implication to the formation of carbonate-bound cadmium.

    PubMed

    Siong, Kian; Asaeda, Takashi

    2009-08-15

    We studied the relationship between macro-algae Chara (Stoneworts) calcite (CaCO(3)) encrustation and the speciation of cadmium (Cd) accumulated by the plant. Results showed that 17% of the total Cd (0.3mgkg(-1)) accumulated by Chara fibrosa exposed to 1 microg Cd L(-1) was carbonate-bound. The percentage of carbonate-bound Cd in the plant exposed to 10 microg Cd L(-1) increased from 48% in young thalli (total Ca<50 mg g(-1), total Cd: 125 mg kg(-1)) to 63% in calcified mature thalli (total Ca: 190 mg g(-1); total Cd: 134 mg kg(-1)). Based on mineral saturation calculation and reliability analysis of the sequential fractionation procedure, precipitation of otavite (CdCO(3)) and co-precipitation of Cd with calcite, occurring in the alkaline regions of Chara cell wall, are probably the mechanisms of carbonate-bound Cd formation. Thick marl sediment frequently found beneath charophyte meadows suggests a long-term storage of Ca as well as the precipitated or co-precipitated Cd in the sediment after the plant senescence and decomposition.

  11. Distribution patterns of the peracarid crustaceans associated with the alga Corallina elongata along the intertidal rocky shores of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Izquierdo, D.; Guerra-García, J. M.

    2011-06-01

    Spatial patterns of intertidal peracarids, associated with the alga Corallina elongata, were studied along the whole Iberian Peninsula. A total of 28,215 specimens were collected, comprising 78 different species (57 amphipods, 16 isopods, 4 tanaids and 1 cumacean), most of them with Atlantic-Mediterranean distribution (60%) and only 9% of Mediterranean endemics. Gammarids were dominant in abundance and number of species, representing more than 70% of the total peracarids. The most common species collected during the present study were the caprellid Caprella penantis, the gammarids Hyale schmidti, Hyale stebbingi, Jassa cf. falcata and Stenothoe monoculoides, the isopod Ischyromene lacazei and the tanaid Tanais dulongii. Caprellids and tanaidaceans presented their highest populations in the stations of the Strait of Gibraltar, whereas isopods were more abundant in Atlantic stations. Univariate analyses did not reflected differences in number of species, abundance and Shannon-Weaver diversity between Mediterranean and Atlantic. However, cluster analyses and Whittaker index, as measure of ß-diversity, showed a different species composition between Mediterranean and Atlantic and a replacement of species along the coast, especially at the Strait of Gibraltar. The turnover mainly affected species of the same genera, probably related with sympatric speciation. CCA and BIO-ENV analyses showed high correlations between environmental measures (especially conductivity) and peracarid distribution. Mediterranean species tolerated higher values of conductivity and temperature, while Atlantic species were associated with stations characterized by higher oxygen concentrations.

  12. Allelopathic effects of macroalga Corallina pilulifera on the red-tide forming alga Heterosigma akashiwo under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Wang, Renjun; Tang, Xuexi

    2016-03-01

    Over the past few years, harmful algal blooms (HABs), such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can alter the structure and succession of aquatic ecosystems. We investigated the influence of four environmental factors (temperature, salinity, light, and pH) on the allelopathic effects of the macroalgae Corallina pilulifera on red-tide forming Heterosigma akashiwo under laboratory conditions. Each of the factors had four levels: temperature (15, 20, 25, and 30°C), salinity (10, 20, 30, and 40), light (20, 100, 200 and 400 μmol/(m2•s)), and pH (5.5, 7, 8.5, and 10. Two-factor experiments were designed for each two environmental factors, with six combination treatments (temperature-salinity, temperature-light, temperature-pH, salinity-light, salinity-pH, and light-pH). Results showed that the allelopathic effect was significantly influenced by temperature, salinity, light, and pH. As single factors, the low temperature (15°C), low salinity (10), high-intensity light (400 μmol/(m2•s)), and high pH (10) treatments substantially enhanced the allelopathic effect. The strongest allelopathic effect of C. pilulifera on H. akashiwo was observed under the following treatments: 15°C and salinity of 40, 25°C and pH 10, 25°C with medium- to high-intensity light at 200-400 μmol/(m 2 •s), 400 μmol/(m2•s) and salinity of 10, 400 μmol/(m2•s) and pH 10, and pH 10 with a salinity of 40.

  13. The mitochondrial genome of Chara vulgaris: insights into the mitochondrial DNA architecture of the last common ancestor of green algae and land plants.

    PubMed

    Turmel, Monique; Otis, Christian; Lemieux, Claude

    2003-08-01

    Mitochondrial DNA (mtDNA) has undergone radical changes during the evolution of green plants, yet little is known about the dynamics of mtDNA evolution in this phylum. Land plant mtDNAs differ from the few green algal mtDNAs that have been analyzed to date by their expanded size, long spacers, and diversity of introns. We have determined the mtDNA sequence of Chara vulgaris (Charophyceae), a green alga belonging to the charophycean order (Charales) that is thought to be the most closely related alga to land plants. This 67,737-bp mtDNA sequence, displaying 68 conserved genes and 27 introns, was compared with those of three angiosperms, the bryophyte Marchantia polymorpha, the charophycean alga Chaetosphaeridium globosum (Coleochaetales), and the green alga Mesostigma viride. Despite important differences in size and intron composition, Chara mtDNA strikingly resembles Marchantia mtDNA; for instance, all except 9 of 68 conserved genes lie within blocks of colinear sequences. Overall, our genome comparisons and phylogenetic analyses provide unequivocal support for a sister-group relationship between the Charales and the land plants. Only four introns in land plant mtDNAs appear to have been inherited vertically from a charalean algar ancestor. We infer that the common ancestor of green algae and land plants harbored a tightly packed, gene-rich, and relatively intron-poor mitochondrial genome. The group II introns in this ancestral genome appear to have spread to new mtDNA sites during the evolution of bryophytes and charalean green algae, accounting for part of the intron diversity found in Chara and land plant mitochondria.

  14. Characterization of the heterotrimeric G-protein complex and its regulator from the green alga Chara braunii expands the evolutionary breadth of plant G-protein signaling.

    PubMed

    Hackenberg, Dieter; Sakayama, Hidetoshi; Nishiyama, Tomoaki; Pandey, Sona

    2013-12-01

    The lack of heterotrimeric G-protein homologs in the sequenced genomes of green algae has led to the hypothesis that, in plants, this signaling mechanism coevolved with the embryophytic life cycle and the acquisition of terrestrial habitat. Given the large evolutionary gap that exists between the chlorophyte green algae and most basal land plants, the bryophytes, we evaluated the presence of this signaling complex in a charophyte green alga, Chara braunii, proposed to be the closest living relative of land plants. The C. braunii genome encodes for the entire G-protein complex, the Gα, Gβ, and Gγ subunits, and the REGULATOR OF G-PROTEIN SIGNALING (RGS) protein. The biochemical properties of these proteins and their cross-species functionality show that they are functional homologs of canonical G-proteins. The subunit-specific interactions between CbGα and CbGβ, CbGβ and CbGγ, and CbGα and CbRGS are also conserved, establishing the existence of functional G-protein complex-based signaling mechanisms in green algae.

  15. Characterization of the heterotrimeric G-protein complex and its regulator from the green alga Chara braunii expands the evolutionary breadth of plant G-protein signaling.

    PubMed

    Hackenberg, Dieter; Sakayama, Hidetoshi; Nishiyama, Tomoaki; Pandey, Sona

    2013-12-01

    The lack of heterotrimeric G-protein homologs in the sequenced genomes of green algae has led to the hypothesis that, in plants, this signaling mechanism coevolved with the embryophytic life cycle and the acquisition of terrestrial habitat. Given the large evolutionary gap that exists between the chlorophyte green algae and most basal land plants, the bryophytes, we evaluated the presence of this signaling complex in a charophyte green alga, Chara braunii, proposed to be the closest living relative of land plants. The C. braunii genome encodes for the entire G-protein complex, the Gα, Gβ, and Gγ subunits, and the REGULATOR OF G-PROTEIN SIGNALING (RGS) protein. The biochemical properties of these proteins and their cross-species functionality show that they are functional homologs of canonical G-proteins. The subunit-specific interactions between CbGα and CbGβ, CbGβ and CbGγ, and CbGα and CbRGS are also conserved, establishing the existence of functional G-protein complex-based signaling mechanisms in green algae. PMID:24179134

  16. Chara myosin and the energy of cytoplasmic streaming.

    PubMed

    Yamamoto, Keiichi; Shimada, Kiyo; Ito, Khoji; Hamada, Saeko; Ishijima, Akio; Tsuchiya, Takayoshi; Tazawa, Masashi

    2006-10-01

    Recently, it was found that myosin generating very fast cytoplasmic streaming in Chara corallina has very high ATPase activity. To estimate the energy consumed by this myosin, its concentration in the internodal cells of C. corallina was determined by quantitative immunoblot. It was found that the concentration of Chara myosin was considerably high (200 nM) and the amount of ATP consumed by this myosin would exceed that supplied by dark respiration if all myosin molecules were fully activated by the interaction with actin. These results and model calculations suggested that the energy required to generate cytoplasmic streaming is very small and only one-hundredth of the existing myosin is enough to maintain the force for the streaming in the Chara cell.

  17. Dynamic aspects of spermiogenic chromatin condensation patterning by phase separation during the histone-to-protamine transition in charalean algae and relation to bryophytes.

    PubMed

    Kasinsky, H E; Ellis, S; Martens, G; Ausió, J

    2014-12-01

    During early-to-middle spermiogenesis in multicellular, internally fertilizing charalean green algae (Chara fibrosa, Chara vulgaris, Chara tomentosa, Nitella missouriensis), patterning of chromatin/nucleoplasm in developing spermatid nuclei changes from granules → fibers → contorted lamellae → condensed chromatin. Cytochemical, immunocytochemical, electrophoretic studies on C. vulgaris and C. tomentosa spermatids (Kwiatkowska, Poplonska) and amino acid analysis of protamines in Chara corallina sperm (Reynolds, Wolfe), indicate that more positively charged protamines replace histones directly during spermiogenesis, not indirectly through other intermediate transitional proteins as in internally fertilizing neogastropods and sharks with more ordered spermatid lamellae. We hypothesize that such lamellar-mediated patterning is due to liquid-liquid phase separation by spinodal decomposition. This is a spontaneous thermodynamic process that involves diffusive instability of a lamellar chromatin network, a dominant pattern repeat distance and bicontinuity of chromatin/nucleoplasm phases. C. vulgaris sperm show contorted lamellae in the posterior region, whereas C. corallina sperm display contorted peripheral lamellae and interior fibrils. Among internally fertilizing liverworts, which may have evolved from Zygnematales, mid-spermatid nuclei lack lamellae. Instead they display self-coiled chromatin rods in Blasia pusilla, contain short chromatin tubules in Haplomitrium hookeri resembling those in internally fertilizing mosses and a hornwort and indirectly replace histones with protamines in Marchantia polymorpha.

  18. Dynamic aspects of spermiogenic chromatin condensation patterning by phase separation during the histone-to-protamine transition in charalean algae and relation to bryophytes.

    PubMed

    Kasinsky, H E; Ellis, S; Martens, G; Ausió, J

    2014-12-01

    During early-to-middle spermiogenesis in multicellular, internally fertilizing charalean green algae (Chara fibrosa, Chara vulgaris, Chara tomentosa, Nitella missouriensis), patterning of chromatin/nucleoplasm in developing spermatid nuclei changes from granules → fibers → contorted lamellae → condensed chromatin. Cytochemical, immunocytochemical, electrophoretic studies on C. vulgaris and C. tomentosa spermatids (Kwiatkowska, Poplonska) and amino acid analysis of protamines in Chara corallina sperm (Reynolds, Wolfe), indicate that more positively charged protamines replace histones directly during spermiogenesis, not indirectly through other intermediate transitional proteins as in internally fertilizing neogastropods and sharks with more ordered spermatid lamellae. We hypothesize that such lamellar-mediated patterning is due to liquid-liquid phase separation by spinodal decomposition. This is a spontaneous thermodynamic process that involves diffusive instability of a lamellar chromatin network, a dominant pattern repeat distance and bicontinuity of chromatin/nucleoplasm phases. C. vulgaris sperm show contorted lamellae in the posterior region, whereas C. corallina sperm display contorted peripheral lamellae and interior fibrils. Among internally fertilizing liverworts, which may have evolved from Zygnematales, mid-spermatid nuclei lack lamellae. Instead they display self-coiled chromatin rods in Blasia pusilla, contain short chromatin tubules in Haplomitrium hookeri resembling those in internally fertilizing mosses and a hornwort and indirectly replace histones with protamines in Marchantia polymorpha. PMID:25262620

  19. Effect of a single excitation stimulus on photosynthetic activity and light-dependent pH banding in Chara cells.

    PubMed

    Bulychev, A A; Kamzolkina, N A; Luengviriya, J; Rubin, A B; Müller, S C

    2004-11-01

    Using pH microelectrodes and a Microscopy PAM (pulse-amplitude modulated) chlorophyll fluorometer, it is shown that a propagation of an action potential in Chara corallina leads to transient suppression of spatially periodic pH profiles along the illuminated cell. The suppression was manifested as a large pH decrease in the alkaline zones and a slight pH increase in the acid zones. The propagating action potential diminished the maximum yield of chlorophyll fluorescence (F(m)') in the alkaline cell regions, as well as the quantum yield of photosystem II photochemistry, without affecting F(m)' in the acid cell regions. The results indicate an interference of membrane excitation in the mechanisms responsible for pH banding patterns in Characean algae. Apparently, the electrical excitation of the plasma membrane in the alkaline cell regions initiates a pathway that can modulate membrane events at the thylakoid membrane.

  20. Microtubule orientation in globular leaflet cells of Chara inflata.

    PubMed

    Iwata, Kazuyoshi; Shimmen, Teruo

    2007-09-01

    Chara inflata has globular leaflet cells and cylindrical internodal cells. The morphology of the leaflet cells is different from that of other Characeae. The orientation of cortical microtubules (MTs) in young leaflet and internodal cells of this species was analyzed by immunofluorescence microscopy. MTs with random orientation were observed in leaflet cells, while those relatively transverse to the cell axis were observed in cylindrical internodal cells. In cylindrical leaflet cells in Chara corallina, transverse MTs were observed. These results imply that C. inflata is a morphological mutant lacking a mechanism for orienting cortical MTs transverse in leaflet cells.

  1. Fluorescent phosphocholine--a specific marker for the endoplasmic reticulum and for lipid droplets in Chara internodal cells.

    PubMed

    Foissner, Ilse

    2009-12-01

    The staining pattern of 1,2-bis(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-undecanoyl)-sn-glycero-3-phosphocholine (Bodipy PC) was investigated in internodal cells of the green alga Chara corallina. Ten minutes after dye addition, Bodipy-PC-derived fluorescence appeared in lipid droplets and after 1 h in the cortical endoplasmic reticulum (ER) and in the inner ER tubes. Staining of the ER required energy but was independent of an intact actin or microtubule cytoskeleton and independent of vesicular endocytosis. The size of the lipid droplets varied between 0.25 microm in elongating cells and 3.2 microm in senescent internodes. They moved together with or along the cortical ER cisternae in a cytoskeleton-independent manner or remained immobile up to several minutes. Detachment of lipid droplets from the cortical ER or fusion of lipid droplets was never observed. The results of this study suggest that Bodipy PC is a valuable, less toxic alternative to 3,3'-dihexyloxacarbocyanine iodide (DiOC6) staining of the ER in Chara. They confirm an earlier report about microtubule-dependent cortical ER morphology and dynamics in elongating internodes and offer new perspectives for the study of organelle interactions.

  2. Plasma membrane domains participate in pH banding of Chara internodal cells.

    PubMed

    Schmölzer, Patric M; Höftberger, Margit; Foissner, Ilse

    2011-08-01

    We investigated the identity and distribution of cortical domains, stained by the endocytic marker FM 1-43, in branchlet internodal cells of the characean green algae Chara corallina and Chara braunii. Co-labeling with NBD C(6)-sphingomyelin, a plasma membrane dye, which is not internalized, confirmed their location in the plasma membrane, and co-labelling with the fluorescent pH indicator Lysotracker red indicated an acidic environment. The plasma membrane domains co-localized with the distribution of an antibody against a proton-translocating ATPase, and electron microscopic data confirmed their identity with elaborate plasma membrane invaginations known as charasomes. The average size and the distribution pattern of charasomes correlated with the pH banding pattern of the cell. Charasomes were larger and more frequent at the acidic regions than at the alkaline bands, indicating that they are involved in outward-directed proton transport. Inhibition of photosynthesis by DCMU prevented charasome formation, and incubation in pH buffers resulted in smaller, homogenously distributed charasomes irrespective of whether the pH was clamped at 5.5 or 8.5. These data indicate that the differential size and distribution of charasomes is not due to differences in external pH but reflects active, photosynthesis-dependent pH banding. The fact that pH banding recovered within several minutes in unbuffered medium, however, confirms that pH banding is also possible in cells with evenly distributed charasomes or without charasomes. Cortical mitochondria were also larger and more abundant at the acid bands, and their intimate association with charasomes and chloroplasts suggests an involvement in carbon uptake and photorespiration.

  3. The density of the cell sap and endoplasm of Nitellopsis and Chara

    NASA Technical Reports Server (NTRS)

    Wayne, R.; Staves, M. P.

    1991-01-01

    We measured the densities of the cell sap, endoplasm and cell wall of Nitellopsis obtusa and Chara corallina using interference microscopy, refractometry, immersion refractometry, equilibrium sedimentation and chemical microanalysis techniques. These values are important for the determination of many rheological properties of the cytoplasm as well as for understanding buoyancy regulation, dispersal mechanisms and how cells respond to gravity. The average densities of the cell sap, endoplasm and cell wall are 1,006.9, 1,016.7 and 1,371 kg m-3 for Nitellopsis and 1,005.0, 1,013.9, and 1,355.3 kg m-3 for Chara.

  4. Kinetic mechanism of the fastest motor protein, Chara myosin.

    PubMed

    Ito, Kohji; Ikebe, Mitsuo; Kashiyama, Taku; Mogami, Toshifumi; Kon, Takahide; Yamamoto, Keiichi

    2007-07-01

    Chara corallina class XI myosin is by far the fastest molecular motor. To investigate the molecular mechanism of this fast movement, we performed a kinetic analysis of a recombinant motor domain of Chara myosin. We estimated the time spent in the strongly bound state with actin by measuring rate constants of ADP dissociation from actin.motor domain complex and ATP-induced dissociation of the motor domain from actin. The rate constant of ADP dissociation from acto-motor domain was >2800 s(-1), and the rate constant of ATP-induced dissociation of the motor domain from actin at physiological ATP concentration was 2200 s(-1). From these data, the time spent in the strongly bound state with actin was estimated to be <0.82 ms. This value is the shortest among known values for various myosins and yields the duty ratio of <0.3 with a V(max) value of the actin-activated ATPase activity of 390 s(-1). The addition of the long neck domain of myosin Va to the Chara motor domain largely increased the velocity of the motility without increasing the ATP hydrolysis cycle rate, consistent with the swinging lever model. In addition, this study reveals some striking kinetic features of Chara myosin that are suited for the fast movement: a dramatic acceleration of ADP release by actin (1000-fold) and extremely fast ATP binding rate.

  5. Immunocytochemical and ultrastructural analyses of the function of the ubiquitin-proteasome system during spermiogenesis with the use of the inhibitors of proteasome proteolytic activity in the alga, Chara vulgaris.

    PubMed

    Wojtczak, Agnieszka; Kwiatkowska, Maria

    2008-04-01

    Spermiogenesis in Chara vulgaris and in animals share many common features, including exchange of nucleohistones into nucleoprotamines, remodeling and extreme condensation of chromatin, formation of flagellae and of microtubule manchette, and decrease in cytoplasm volume. In C. vulgaris, spermiogenesis is not preceded by meiosis since this alga is a haplobiont. In the present work we showed that in early spermiogenesis characterized by a significant metabolic activity of spermatids, the inhibitors of proteasomes did not visibly change their ultrastructure but significantly prolonged this process. At late stages of spermiogenesis, MG-132 and epoxomicin dramatically changed the structure of nuclei: regular fibrillar and lamellar structure of chromatin was disturbed and clusters of grains corresponding to aggresomes appeared, but the nucleus shape and cytoplasm structure were the same as in the controls. Immunocytochemical studies revealed that these inhibitors blocked disappearance of histones from nuclei while the structures corresponding to aggresomes were clusters of undegraded ubiquitinated histones, since they gave positive immunosignals indicating the presence of ubiquitin and histones.

  6. The enigmatic genome of Chara australis virus.

    PubMed

    Gibbs, Adrian J; Torronen, Marjo; Mackenzie, Anne M; Wood, Jeffery T; Armstrong, John S; Kondo, Hideki; Tamada, Tetsuo; Keese, Paul L

    2011-11-01

    Most of the genomic sequence of Chara australis virus (CAV), previously called Chara corallina virus, has been determined. It is a ssRNA molecule of 9065 nt with at least four ORFs. At its 5' end is an ORF encoding a protein of 227 kDa, distantly homologous to the multifunctional replicases of benyviruses and rubiviruses. Next is an ORF encoding a protein of 44 kDa, homologous to the helicases of pestiviruses. The third ORF encodes an unmatched protein of 38 kDa that is probably a movement protein. The fourth and 3'-terminal ORF encodes a protein of 17.7 kDa homologous to the coat proteins of tobamoviruses. The short methyltransferase region of the CAV replicase matches only the C-terminal motif of benyvirus methyltransferases. This and other clues indicate that approximately 11% and 2% of the 5' and 3' termini of the complete CAV genome, respectively, are missing from the sequence. The aligned amino acid sequences of the CAV proteins and their nearest homologues contain many gaps but relationships inferred from them were little affected by removal of these gaps. Sequence comparisons show that three of the CAV genes may have diverged from the most closely related genes of other viruses 250-450 million years ago, and the sister relationship between the genes of CAV and those of benyviruses and tobamoviruses, mirroring the ancient sister relationship between charophytes (i.e. the algal host of CAV) and embryophytes (i.e. the plant hosts of tobamoviruses and benyviruses), is congruent with this possibility.

  7. Electrical perception of the 'death message' in Chara: characterization of K+ -induced depolarization.

    PubMed

    Shimmen, Teruo

    2006-04-01

    When the nodal end of an internodal cell of Chara corallina was subjected to a pulse treatment with artificial cell sap, a depolarization lasted in artificial pond water. This depolarization could also be induced by pulse treatment with KCl solution, indicating that K+ in the artificial cell sap is responsible (K+ -induced depolarization). The depolarization was prolonged in the presence of 2 mM KCl and the prolonged depolarization was terminated by supplementing with either CaCl2, MgCl2 or NaCl. These results supported the hypothesis that K+ released from the killed cell is responsible for generation of the wound-induced membrane depolarization.

  8. Studies on semipermeability and electrical characteristics in membranes of Chara cells fixed with glutaraldehyde.

    PubMed

    Shimmen, Teruo

    2004-08-01

    When internodal cells of Chara corallina were incubated in a solution containing 1% glutaraldehyde, an increase in intracellular osmolality was observed, and this indicates that the plasma membrane maintained its semipermeability. The effect on the membrane potential was studied. Although the active component generated by the electrogenic proton pump was lost, the passive component (more negative than -100 mV) was maintained during glutaraldehyde treatment for more than 1-2 h. The membrane resistance increased significantly. It was found that the tonoplasts also maintained their semipermeability during glutaraldehyde treatment.

  9. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-01

    Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs.

  10. The CHARA optical array

    NASA Astrophysics Data System (ADS)

    McAlister, Harold A.

    1992-11-01

    The Center for High Angular Resolution Astronomy (CHARA) was established in the College of Arts and Sciences at Georgia State University in 1984 with the goals of designing, constructing, and then operating a facility for very high spatial resolution astronomy. The interest in such a facility grew out of the participants' decade of activity in speckle interferometry. Although speckle interferometry continues to provide important astrophysical measurements of a variety of objects, many pressing problems require resolution far beyond that which can be expected from single aperture telescopes. In early 1986, CHARA received a grant from the National Science Foundation which has permitted a detailed exploration of the feasibility of constructing a facility which will provide a hundred-fold increase in angular resolution over what is possible by speckle interferometry at the largest existing telescopes. The design concept for the CHARA Array was developed initially with the contractural collaboration of United Technologies Optical Systems, Inc., in West Palm Beach, Florida, an arrangement that expired in August 1987. In late November 1987, the Georgia Tech Research Institute joined with CHARA to continue and complete the design concept study. Very high-resolution imaging at optical wavelengths is clearly coming of age in astronomy. The CHARA Array and other related projects will be important and necessary milestones along the way toward the development of a major national facility for high-resolution imaging--a true optical counterpart to the Very Large Array. Ground-based arrays and their scientific output will lead to high resolution facilities in space and, ultimately, on the Moon.

  11. Algae.

    PubMed

    Raven, John A; Giordano, Mario

    2014-07-01

    Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs. PMID:25004359

  12. The statolith compartment in Chara rhizoids contains carbohydrate and protein

    NASA Technical Reports Server (NTRS)

    Wang-Cahill, F.; Kiss, J. Z.

    1995-01-01

    In contrast to higher plants, the alga Chara has rhizoids with single membrane-bound compartments that function as statoliths in gravity perception. Previous work has demonstrated that these statoliths contain barium sulfate crystals. In this study, we show that statoliths in Chara rhizoids react with a Coomassie Brilliant Blue cytochemical stain for proteins. While statoliths did not react with silver methenamine carbohydrate cytochemistry, the monoclonal antibody CCRC-M2, which is against a carbohydrate (sycamore-maple rhamnogalacturonan I), labeled the statolith compartment. These results demonstrate that in addition to barium sulfate, statoliths in Chara rhizoids have an organic matrix that consists of protein and carbohydrate moieties. Since the statoliths were silver methenamine negative, the carbohydrate in this compartment could be a 3-linked polysaccharide. CCRC-M2 also labeled Golgi cisternae, Golgi-associated vesicles, apical vesicles, and cell walls in the rhizoids. The specificity of CCRC-M2 immunolabeling was verified by several control experiments, including the demonstration that labeling was abolished when the antibody was preabsorbed with its antigen. Since in this and a previous study (John Z. Kiss and L. Andrew Staehelin, American Journal of Botany 80: 273-282, 1993) antibodies against higher plant carbohydrates crossreacted with cell walls of Chara in a specific manner, Characean algae may be a useful model system in biochemical and molecular studies of cell walls.

  13. Pectate chemistry links cell expansion to wall deposition in Chara corallina.

    PubMed

    Proseus, Timothy E; Boyer, John S

    2012-11-01

    Pectate (polygalacturonic acid) acts as a chelator to bind calcium and form cross-links that hold adjacent pectate polymers and thus plant cell walls together. When under tension from turgor pressure in the cell, the cross-links appear to distort and weaken. New pectate supplied by the cytoplasm is undistorted and removes wall calcium preferentially from the weakened bonds, loosening the wall and accelerating cell expansion. The new pectate now containing the removed calcium can bind to the wall, strengthening it and linking expansion to wall deposition. But new calcium needs to be added as well to replenish the calcium lost from the vacated wall pectate.  A recent report demonstrated that growth was disrupted if new calcium was unavailable.  The present addendum highlights this conclusion by reviewing an experiment from before the chelation chemistry was understood. Using cell wall labeling, a direct link appeared between wall expansion and wall deposition. Together, these experiments support the concept that newly supplied pectate has growth activity on its way to deposition in the wall. Growth rate is thus controlled by signals affecting the rate of pectate release. After release, the coordination of expansion and deposition arises naturally from chelation chemistry when polymers are under tension from turgor pressure. 

  14. [Transient currents and Ca2+ gradient relaxation in characean algae cells: theory and experiment].

    PubMed

    Berestovskiĭ, G N; Kataev, A A; Tsyganov, M A

    2006-01-01

    Transient Ca2+ and Ca2+-dependent Cl- currents of plasmatic membranes of voltage-clamped Chara corallina freshwater alga cells were studied. Our earlier described method was used for rapid (approximately 10 ms) injection of Ca2+ ions into the cell during the deactivation period of calcium channels following their activation by a positive voltage pulse (injection by "tail" Ca2+ current). This procedure allowed one to determine the amplitude of the Ca2+ component, as well as the amplitude and kinetics of the submembrane Ca2+ concentration-dependent Cl- component for the transient current. Calculations based on the cell model allowing for Ca2+ diffusion, the Ca2+-buffering properties of the cytoplasm, and the nonlinear dependency of iCl on [Ca2+]cyt, as well as the presence of chloroplasts agreed well with the experimentally observed behavior of the transient current. The slow stage of the [Ca2+]cyt relaxation to the resting level (approximately 10(-7) M), related to the functioning of Ca2+-ATPases, was shown to take approximately 10(2) s. We assume this stage to determine the duration of the refractory period after the generation of action potential.

  15. Cyclosis-mediated transfer of H2O 2 elicited by localized illumination of Chara cells and its relevance to the formation of pH bands.

    PubMed

    Eremin, Alexey; Bulychev, Alexander; Hauser, Marcus J B

    2013-12-01

    Cytoplasmic streaming occurs in most plant cells and is vitally important for large cells as a means of long-distance intracellular transport of metabolites and messengers. In internodal cells of characean algae, cyclosis participates in formation of light-dependent patterns of surface pH and photosynthetic activity, but lateral transport of regulatory metabolites has not been visualized yet. Hydrogen peroxide, being a signaling molecule and a stress factor, is known to accumulate under excessive irradiance. This study was aimed to examine whether H2O2 produced in chloroplasts under high light conditions is released into streaming fluid and transported downstream by cytoplasmic flow. To this end, internodes of Chara corallina were loaded with the fluorogenic probe dihydrodichlorofluorescein diacetate and illuminated locally by a narrow light beam through a thin optic fiber. Fluorescence of dihydrodichlorofluorescein (DCF), produced upon oxidation of the probe by H2O2, was measured within and around the illuminated cell region. In cells exhibiting active streaming, H2O2 first accumulated in the illuminated region and then entered into the streaming cytoplasm, giving rise to the expansion of DCF fluorescence downstream of the illuminated area. Inhibition of cyclosis by cytochalasin B prevented the spreading of DCF fluorescence along the internode. The results suggest that H2O2 released from chloroplasts under high light is transported along the cell with the cytoplasmic flow. It is proposed that the shift of cytoplasmic redox poise and light-induced elevation of cytoplasmic pH facilitate the opening of H(+)/OH(-)-permeable channels in the plasma membrane.

  16. Cyclosis-mediated transfer of H2O 2 elicited by localized illumination of Chara cells and its relevance to the formation of pH bands.

    PubMed

    Eremin, Alexey; Bulychev, Alexander; Hauser, Marcus J B

    2013-12-01

    Cytoplasmic streaming occurs in most plant cells and is vitally important for large cells as a means of long-distance intracellular transport of metabolites and messengers. In internodal cells of characean algae, cyclosis participates in formation of light-dependent patterns of surface pH and photosynthetic activity, but lateral transport of regulatory metabolites has not been visualized yet. Hydrogen peroxide, being a signaling molecule and a stress factor, is known to accumulate under excessive irradiance. This study was aimed to examine whether H2O2 produced in chloroplasts under high light conditions is released into streaming fluid and transported downstream by cytoplasmic flow. To this end, internodes of Chara corallina were loaded with the fluorogenic probe dihydrodichlorofluorescein diacetate and illuminated locally by a narrow light beam through a thin optic fiber. Fluorescence of dihydrodichlorofluorescein (DCF), produced upon oxidation of the probe by H2O2, was measured within and around the illuminated cell region. In cells exhibiting active streaming, H2O2 first accumulated in the illuminated region and then entered into the streaming cytoplasm, giving rise to the expansion of DCF fluorescence downstream of the illuminated area. Inhibition of cyclosis by cytochalasin B prevented the spreading of DCF fluorescence along the internode. The results suggest that H2O2 released from chloroplasts under high light is transported along the cell with the cytoplasmic flow. It is proposed that the shift of cytoplasmic redox poise and light-induced elevation of cytoplasmic pH facilitate the opening of H(+)/OH(-)-permeable channels in the plasma membrane. PMID:23760663

  17. Possible involvement of mechanosensitive Ca2+ channels of plasma membrane in mechanoperception in Chara.

    PubMed

    Kaneko, Toshiyuki; Saito, Chiyuki; Shimmen, Teruo; Kikuyama, Munehiro

    2005-01-01

    When an internodal cell of Chara corallina was stimulated with a mechanical pulse of various amplitudes lasting for 0.1 s (mechanical stimulus), the cell generated a receptor potential, which was highly dependent not only on the strength of the stimulus but also on the extracellular Cl- concentration. Extracellular Ca2+ was indispensable for generating receptor potential, since removal of Ca2+ reversibly inhibited generation of the receptor potential. The cytoplasmic Ca2+ level transiently rose upon mechanical stimulation. The stronger the mechanical stimulus, the larger was the increase in the cytoplasmic level of Ca2+. It is proposed that the first step of receptor potential is an activation of mechanosensitive Ca2+ channels at the plasma membrane.

  18. CHARA recent technology and science

    NASA Astrophysics Data System (ADS)

    McAlister, Harold A.; ten Brummelaar, Theo A.; Aufdenberg, Jason P.; Bagnuolo, William G.; Berger, David H.; Coudé du Foresto, Vincent; Merand, Antoine; Ogden, Chad; Ridgway, Stephen T.; Sturmann, Judit; Sturmann, Laszlo; Taylor, Stuart; Turner, Nils H.

    2004-10-01

    Georgia State University's Center for High Angular Resolution Astronomy (CHARA) operates a multi-telescope, long-baseline, optical/infrared interferometric array on Mt. Wilson, California. We present an update on the status of this facility along with a sample of preliminary results from current scientific programs.

  19. Progress on the CHARA array

    NASA Astrophysics Data System (ADS)

    McAlister, Harold A.; Bagnuolo, William G.; ten Brummelaar, Theo A.; Hartkopf, W. I.; Shure, Mark A.; Sturmann, Laszlo; Turner, Nils H.; Ridgway, Stephen T.

    1998-07-01

    The Center for High Angular Resolution Astronomy (CHARA) at Georgia State University is building an interferometric array of telescope for high resolution imaging at optical and IR wavelengths. The 'CHARA Array' will initially consist of five 1-m diameter telescopes arranged in a 'Y' shaped configuration with a maximum baseline of approximately 350 m. The facility is being constructed on Mt. Wilson, near Pasadena, California, a site noted for stable atmospheric conditions that often gives rise to exceptional image quality. The Array will be capable of submilliarcsecond imaging and will be devoted to a broad program of science aimed at fundamental stellar astrophysics in the visible and the astrophysics of young stellar objects in the IR spectral regions. This project is being funded in approximately 50/50 percent shares by Georgia State University and the National Science Foundation. The CHARA Array is expected to become operational during 1999. This paper presents a projection status report. An extensive collection of project reports and images are available at our website (http:/www.chara.gsu.edu).

  20. Planomonospora corallina sp. nov., isolated from soil.

    PubMed

    Suriyachadkun, Chanwit; Ngaemthao, Wipaporn; Chunhametha, Suwanee

    2016-08-01

    A novel actinomycete strain, A-T 11038T, was isolated from bamboo rhizospheric soil collected in Thailand. Based on a polyphasic approach, the novel strain was characterized as a member of the genus Planomonospora, which developed cylindrical to clavate sporangia containing a single motile spore on aerial mycelium. The 16S rRNA gene sequence and phylogenetic analysis indicated that strain A-T 11038T was closely related to Planomonospora sphaerica JCM 9374T (98.82 %), P.lanomonospora parontospora subsp. parontospora NBRC 13880T and P.parontospora subsp. antibiotica JCM 3094T (98.54 %), Planomonospora alba JCM 9373T (98.41 %) and Planomonospora venezuelensis JCM 3167T (97.51 %). The DNA-DNA relatedness values that distinguished strain A-T 11038T from the most closely related species were below 45 %. The novel strain contained meso-diaminopimelic acid in cell-wall hydrolysates, and rhamnose, ribose, madurose and glucose in whole-cell hydrolysates. The predominant menaquinone was MK-9(H2). The diagnostic phospholipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol mannosides, phosphatidylinositol and aminophosphoglycolipids. The predominant cellular fatty acids were unsaturated fatty acids C17 : 1 and C16 : 1 and saturated fatty acid C16 : 0. The G+C content of the genomic DNA was 73.5 mol%. Following the evidence obtained using a polyphasic approach, the novel strain is proposed as a representative of a novel species to be named Planomonospora corallina sp. nov. The type strain is A-T 11038T (=BCC 67829T=TBRC 4489T=NBRC 110609T). PMID:27217033

  1. Further quantification of the role of internal unstirred layers during the measurement of transport coefficients in giant internodes of Chara by a new stop-flow technique.

    PubMed

    Kim, Yangmin; Ye, Qing; Reinhardt, Hagen; Steudle, Ernst

    2006-01-01

    A new stop-flow technique was employed to quantify the impact of internal unstirred layers on the measurement of the solute permeability coefficient (P(s)) across the plasma membrane of internodes of the giant-celled alga Chara corallina using a cell pressure probe. During permeation experiments with rapidly permeating solutes (acetone, 2-propanol, and dimethylformamide), the solute concentration inside the cell was estimated and the external medium was adjusted to stop solute transport across the membrane, after which responses in turgor were measured. This allowed estimation of the solute concentration right at the membrane. Stop-flow experiments were also simulated with a computer. Both the stop-flow experiments and simulations provided quantitative data about internal concentration gradients and the contribution of unstirred layers to overall measured values of P(meas)(s) for the three solutes. The stop-flow experimental results agreed with stop-flow simulations assuming that solutes diffused into a completely stagnant cell interior. The effects of internal unstirred layers on the underestimation of membrane P(s) declined with decreasing P(s). They were no bigger than 37% in the presence of the most rapidly permeating solute, acetone (P(meas)(s) =4.2 x 10(-6) m s(-1)), and 14% for the less rapidly permeating dimethylformamide (P(meas)(s) =1.6x10(-6) m s(-1)). It is concluded that, even in the case of rapidly permeating solutes such as isotopic water and, even when making pessimistic assumptions about the internal mixing of solutes, an upper limit for the underestimation of P(s) due to internal unstirred layers was 37%. The data are discussed in terms of recent theoretical estimates of the effect of internal unstirred layers and in terms of some recent criticism of cell pressure probe measurements of water and solute transport coefficients. The current stop-flow data are in line with earlier estimations of the role of unstirred layers in the literature on cell

  2. Misleading morphologies and the importance of sequencing type specimens for resolving coralline taxonomy (Corallinales, Rhodophyta): Pachyarthron cretaceum is Corallina officinalis.

    PubMed

    Hind, Katharine R; Gabrielson, Paul W; Lindstrom, Sandra C; Martone, Patrick T

    2014-08-01

    Coralline red algae play a key role in the ecology of near shore marine ecosystems and are increasingly being used to study the effects of climate change in the marine environment. Corallines are very difficult to identify to species, and even to genus, using morpho-anatomy, likely complicating studies of their ecology, physiology, and biodiversity. We sequenced a 296 base pair fragment of chloroplast DNA from a 187-year-old isolectotype specimen of Pachyarthron cretaceum, a morphologically distinct geniculate species, to demonstrate that coralline morphology is often misleading and that species names can only be applied unequivocally by comparing DNA sequences from type material with sequences from field-collected specimens. Our results indicate that Pachyarthron cretaceum is synonymous with Corallina officinalis.

  3. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-01

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies. PMID:27135491

  4. Cellular Auxin Transport in Algae.

    PubMed

    Zhang, Suyun; van Duijn, Bert

    2014-01-27

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies.

  5. Cytochemical and immunocytochemical studies of the localization of histones and protamine-type proteins in spermatids of Chara vulgaris and Chara tomentosa.

    PubMed

    Popłońska, Katarzyna; Wojtczak, Agnieszka; Kwiatkowska, Maria; Kaźmierczak, Andrzej

    2007-01-01

    Spermiogenesis in Chara algae, which has been divided into 10 phases (sp I-X), is similar to spermiogenesis in animals. The most important process during spermiogenesis in animals is remodeling of chromatin leading to "sleeping genome", being the result the exchange of histone proteins into protamine-like proteins. Cytochemical studies showed in both Chara species (C. vulgaris, C. tomentosa) that at spI-IV phases only histones were present, at spV-VIII phases--the amount of nuclear protamine-type proteins progressively increased and that of histones decreased while at spIX-X only pro-tamine-type proteins were present. This was also confirmed with capillar electrophoresis. In order to localize more precisely both histones and protamines the immunocytochemical studies with the use of anti-protamine antibodies (protamine-type proteins were obtained from C. tomentosa antheridia) and anti-histone H3 antibodies, have been carried out. More specific immunocytochemical studies confirmed cytochemical results including the exchange of histones into protamine-type during spermiogenesis (spV-VIII) in both Chara species. At phase V spermiogenesis these strong strand-like anti-protamine signals were observed in cytoplasm which might suggest that protamine synthesis took place in ER.

  6. CHARA Array Enclosure Control System

    NASA Astrophysics Data System (ADS)

    Hines, Braden E.; ten Brummelaar, Theo A.

    2002-12-01

    The CHARA Array at Mt. Wilson consists of six telescopes spread over hundreds of meters of rugged territory. Making efficient use of such a large physical instrument requires automation and tele-operation of the distributed resources. One system which is key to making daily operations routine is the enclosure control system, which is used to open and close the walls of the enclosure in order to enable quick equilibration of the telescope with its environment in order to minimize ground seeing effects on observations. This paper describes this enclosure control system, which is a distributed hardware/software system consisting of software running on a central control station in the operations room, together with software and hardware installed on six remote computers. The system must be robust in the presence of absent or intermittent nodes or network connections, must provide for both manual or remote control of the enclosures, and must provide for hardware and personnel safety. Remote operation of the system from Atlanta, Georgia has been demonstrated, and the system has proven extremely robust in regular use to date.

  7. On the mechanism of uranium binding to cell wall of Chara fragilis.

    PubMed

    Daković, Marko; Kovacević, Maja; Andjus, Pavle R; Bacić, Goran

    2008-09-01

    Biosorption of uranium from nuclear waste liquids and contaminated surface waters and soils has recently attracted special interest. However, the detailed mechanism of uranium uptake by plants is not well understood. The aim of this work is to investigate the role of cell wall components of the freshwater alga Chara fragilis in uranium sequestration from its solution. Three types of algae preparations: extract of cell wall polysaccharides, dried and live algae were subjected to uranium solutions of different concentration and pH. FTIR and X-ray diffraction were used to assess both potential binding sites and the form of the uranyl sequestered by algae. Sorption of uranium by live and dry algae shows remarkable differences both in terms of overall uptake and mechanisms involved. All experiments are consistent with the conclusion that coprecipitation of uranyl species with CaCO3 is the major binding mechanism in uranium sequestration by Chara fragilis, while the direct exchange of Ca2+ with UO22+ has a minor role. Live algae are twice as efficient in sequestering uranium from solution than dried ones due to the formation of different crystalline forms such as aragonite and rutherfordine forming in live algae in the presence of the uranyl species in solution. It therefore appears that metabolic processes such as photosynthesis, most likely through the regulation of pH, play a key role in the uranium uptake by plants. Further understanding of the complex mechanism of metabolic control of the uranium uptake by plants is needed before the planning of bioremediation of this element.

  8. Cd tolerance and accumulation in the aquatic macrophyte, Chara australis: potential use for charophytes in phytoremediation.

    PubMed

    Clabeaux, Bernadette L; Navarro, Divina A G; Aga, Diana S; Bisson, Mary A

    2011-06-15

    We investigated the potential use of the alga Chara australis (R. Br.) forphytore mediation of Cd-contaminated sediments in aquatic systems. Chara tolerated up to 20 mg added Cd (kg soil)⁻¹ in laboratory culture. Chlorophyll a and b levels were not affected even at Cd concentrations that suppressed growth. Levels of glutathione were suppressed at 2-35 mg added Cd (kg soil)⁻¹ to 200-350 nmol GSH (g DW)⁻¹, while control levels were 660 nmol GSH (g DW)⁻¹). Histochemical studies showed Cd occurred throughout cell walls and cytoplasm in plants grown in 5-20 mg Cd (kg soil)⁻¹. Quantification using ICP-MS showed the maximum concentration in shoots was 72 mg Cd (kg DW)⁻¹ at 35 mg added Cd (kg soil)⁻¹, while the maximum in rhizoids was 116 mg Cd (kg DW)⁻¹ at 25 mg added Cd (kg soil)⁻¹. The bioconcentration factor (BCF, concentration in plant/concentration in soil) exceeded 1.0, the critical value for hyperaccumulators, for shoots exposed to 35 mg Cd (kg soil)⁻¹ and rhizoids exposed to ≥25 mg Cd (kg soil)⁻¹. Translocation factors (TF, shoot concentration/rhizoid concentration) did not exceed 1.0 for any treatment. While Chara cannot be considered a hyperaccumulator, it shows promise for use in phytoremediation efforts.

  9. A Prototype Imager for the CHARA Array

    NASA Astrophysics Data System (ADS)

    Turner, Nils Henning

    1998-11-01

    Traditional methods of data collection in active fringe tracking Michelson stellar interferometers involve logging and analyzing the signals within the fringe tracking system for the scientific information about the object being observed. While these methods are robust and have produced excellent scientific results, they become more problematic as next-generation Michelson stellar interferometers are built with more telescopes and the aim of performing routine imaging. The Center for High Angular Resolution Astronomy (CHARA) Array is one such next-generation instrument presently under construction on Mount Wilson, north of Los Angeles, California. The CHARA Array will feature a separation of the tasks of active fringe tracking and imaging, thereby increasing the bandwidth, sensitivity, and data acquisition rate. Presented is a prototype version of an imager for the CHARA Array. The prototype imager employs single-mode fiber optic strands to convey the light from simulated telescopes to a smaller, non-redundant, remapped pupil plane, which in turn feeds a low resolution prism spectrograph. The spectrograph features two cylindrical optical elements whose net effect is to focus the light to a smaller plate scale in the spectral dimension than in the orthogonal spatial dimension. The actual Array imager will build on lessons learned from the prototype and will include capability for five telescopes, further degrees of freedom in adjustment, a computer interface, and automatic intensity calibration.

  10. Biosorption characteristics of copper (II), chromium (III), nickel (II), and lead (II) from aqueous solutions by Chara sp. and Cladophora sp.

    PubMed

    Elmaci, Ayşe; Yonar, Taner; Ozengin, Nihan

    2007-09-01

    The aim of this research was to expose individual removals of copper, chromium, nickel, and lead from aqueous solutions via biosorption using nonliving algae species, Chara sp. and Cladophora sp. Optimum pH values for biosorption of copper (II), chromium (III), nickel (II), and lead (II) from aqueous solutions were determined to be 6, 7, 7, and 3 for Cladophora sp. and 5, 3, 5, and 4 for Chara sp. respectively. Maximum adsorption capacities of Chara sp. [10.54 for chromium (III) and 61.72 for lead (II)] and Cladophora sp. [6.59 for chromium (III) and 16.75 and 23.25 for lead (II)] for chromium (III) and lead (II) are similar. On the other hand, copper (II) and nickel (II) biosorption capacity of Cladophora sp. [14.28 for copper (II) and 16.75 for nickel (II)] is greater than Chara sp. [6.506 for copper (II) and 11.76 for nickel (II)]. Significantly high correlation coefficients indicated for the Langmuir adsorption isotherm models can be used to describe the equilibrium behavior of copper, chromium, nickel, and lead adsorption onto Cladophora sp. and Chara sp.

  11. Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception.

    PubMed

    Bulychev, Alexander A; Alova, Anna V; Bibikova, Tatiana N

    2013-11-01

    Mechanical wounding of cell walls occurring in plants under the impact of pathogens or herbivores can be mimicked by cell wall incision with a glass micropipette. Measurements of pH at the surface of Chara corallina internodes following microperforation of cell wall revealed a rapid (10-30s) localized alkalinization of the apoplast after a lag period of 10-20s. The pH increase induced by incision could be as large as 3 pH units and relaxed slowly, with a halftime up to 20min. The axial pH profile around the incision zone was bell-shaped and localized to a small area, extending over a distance of about 100μm. The pH response was suppressed by lowering cell turgor upon the replacement of artificial pond water (APW) with APW containing 50mM sorbitol. Stretching of the plasma membrane during its impression into the cell wall defect is likely to activate the Ca(2+) channels, as evidenced from sensitivity of the incision-induced alkalinization to the external calcium concentration and to the addition of Ca(2+)-channel blockers, such as La(3+), Gd(3+), and Zn(2+). The maximal pH values attained at the incision site (~10.0) were close to pH in light-dependent alkaline zones of Chara cells. The involvement of cytoskeleton in the origin of alkaline patch was documented by observations that the incision-induced pH transients were suppressed by the inhibitors of microtubules (oryzalin and taxol) and, to a lesser extent, by the actin inhibitor (cytochalasin B). The results indicate that the localized increase in apoplastic pH is an early event in mechanoperception and depends on light, cytoskeleton, and intracellular calcium.

  12. Transitions from alkaline spots to regular bands during pH pattern formation at the plasmalemma of Chara cells.

    PubMed

    Bulychev, A A; Zykov, S V; Rubin, A B; Müller, S C

    2003-05-01

    A scanning pH-microprobe was used to study pH patterns near the surface of Chara corallina cells at various light intensities and during light-induced transitions from homogeneous pH distribution to alternating pH bands. In the irradiance (PAR) range 4-400 micromol quanta m(-2) s(-1), the sustained pH profiles consisted of alternating acid and alkaline bands with a characteristic length of 7-10 mm and pH shifts as large as 2-3 units. At lower irradiance, the number of alkaline bands decreased while the amplitude of remaining peaks stayed high. On cyclic changes in light intensity, a hysteresis of pH banding was observed: the pH bands tolerated low irradiance in weakening light, but higher irradiance was required for their emergence after dark adaptation of the cell. The pH profiles measured for different paths of electrode scanning suggest that the pH pattern at low light level represents patches coexisting with bands. The exposure of the cell to high-intensity light led to formation of radially symmetrical bands. Transformations of the pH pattern induced by lowering the light intensity were similar to those induced by transcellular electric current (1.5-3 microA). The data suggest that band formation at the plasmalemma of Chara cells proceeds through the initial appearance of multiple patches with a localized H(+)-transporting activity and subsequent spot rearrangements (fusion, deletions, widening), leading to establishment of alternating bands.

  13. Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception.

    PubMed

    Bulychev, Alexander A; Alova, Anna V; Bibikova, Tatiana N

    2013-11-01

    Mechanical wounding of cell walls occurring in plants under the impact of pathogens or herbivores can be mimicked by cell wall incision with a glass micropipette. Measurements of pH at the surface of Chara corallina internodes following microperforation of cell wall revealed a rapid (10-30s) localized alkalinization of the apoplast after a lag period of 10-20s. The pH increase induced by incision could be as large as 3 pH units and relaxed slowly, with a halftime up to 20min. The axial pH profile around the incision zone was bell-shaped and localized to a small area, extending over a distance of about 100μm. The pH response was suppressed by lowering cell turgor upon the replacement of artificial pond water (APW) with APW containing 50mM sorbitol. Stretching of the plasma membrane during its impression into the cell wall defect is likely to activate the Ca(2+) channels, as evidenced from sensitivity of the incision-induced alkalinization to the external calcium concentration and to the addition of Ca(2+)-channel blockers, such as La(3+), Gd(3+), and Zn(2+). The maximal pH values attained at the incision site (~10.0) were close to pH in light-dependent alkaline zones of Chara cells. The involvement of cytoskeleton in the origin of alkaline patch was documented by observations that the incision-induced pH transients were suppressed by the inhibitors of microtubules (oryzalin and taxol) and, to a lesser extent, by the actin inhibitor (cytochalasin B). The results indicate that the localized increase in apoplastic pH is an early event in mechanoperception and depends on light, cytoskeleton, and intracellular calcium. PMID:23850637

  14. A cohesion/tension mechanism explains the gating of water channels (aquaporins) in Chara internodes by high concentration.

    PubMed

    Ye, Qing; Wiera, Boguslaw; Steudle, Ernst

    2004-02-01

    Isolated internodes of Chara corallina have been used to study the gating of aquaporins (water channels) in the presence of high concentrations of osmotic solutes of different size (molecular weight). Osmolytes were acetone and three glycol ethers: ethylene glycol monomethyl ether (EGMME), diethylene glycol monomethyl ether (DEGMME), and triethylene glycol monoethyl ether (TEGMEE). The 'osmotic efficiency' of osmolytes was quite different. Their reflection coefficients ranged between 0.15 (acetone), 0.59 (EGMME), 0.78 (DEGMME), and 0.80 (TEGMEE). Bulk water permeability (Lp) and diffusive permeabilities (Ps) of heavy water (HDO), hydrogen peroxide (H2O2), acetone, and glycol ethers (EGMME, DEGMME, and TEGMEE) were measured using a cell pressure probe. Cells were treated with different concentrations of osmotic solutes of up to 800 mM ( approximately 2.0 MPa of osmotic pressure). Inhibition of aquaporin activity increased with both increasing concentration and size of solutes (reflection coefficients). As cell Lp decreased, Ps increased, indicating that water and solutes used different passages across the plasma membrane. Similar to earlier findings of an osmotic gating of ion channels, a cohesion/tension model of the gating of water channels in Chara internodes by high concentration is proposed. According to the model, tensions (negative pressures) within water channels affected the open/closed state by changing the free energy between states and favoured a distorted/collapsed rather than the open state. They should have differed depending on the concentration and size of solutes that are more or less excluded from aquaporins. The bigger the solute, the lower was the concentration required to induce a reversible closure of aquaporins, as predicted by the model.

  15. Feed-forward regulation of microbisporicin biosynthesis in Microbispora corallina.

    PubMed

    Foulston, Lucy; Bibb, Mervyn

    2011-06-01

    Lantibiotics are ribosomally synthesized, posttranslationally modified peptide antibiotics. Microbisporicin is a potent lantibiotic produced by the actinomycete Microbispora corallina and contains unique chlorinated tryptophan and dihydroxyproline residues. The biosynthetic gene cluster for microbisporicin encodes several putative regulatory proteins, including, uniquely, an extracytoplasmic function (ECF) σ factor, σ(MibX), a likely cognate anti-σ factor, MibW, and a potential helix-turn-helix DNA binding protein, MibR. Here we examine the roles of these proteins in regulating microbisporicin biosynthesis. S1 nuclease protection assays were used to determine transcriptional start sites in the microbisporicin gene cluster and confirmed the presence of the likely ECF sigma factor -10 and -35 sequences in five out of six promoters. In contrast, the promoter of mibA, encoding the microbisporicin prepropeptide, has a typical Streptomyces vegetative sigma factor consensus sequence. The ECF sigma factor σ(MibX) was shown to interact with the putative anti-sigma factor MibW in Escherichia coli using bacterial two-hybrid analysis. σ(MibX) autoregulates its own expression but does not directly regulate expression of mibA. On the basis of quantitative reverse transcriptase PCR (qRT-PCR) data, we propose a model for the biosynthesis of microbisporicin in which MibR functions as an essential master regulator and the ECF sigma factor/anti-sigma factor pair, σ(MibX)/MibW, induces feed-forward biosynthesis of microbisporicin and producer immunity.

  16. The CHARA Array Adaptive Optics Program

    NASA Astrophysics Data System (ADS)

    Ten Brummelaar, Theo; Che, Xiao; McAlister, Harold A.; Ireland, Michael; Monnier, John D.; Mourard, Denis; Ridgway, Stephen T.; sturmann, judit; Sturmann, Laszlo; Turner, Nils H.; Tuthill, Peter

    2016-01-01

    The CHARA array is an optical/near infrared interferometer consisting of six 1-meter diameter telescopes the longest baseline of which is 331 meters. With sub-millisecond angular resolution, the CHARA array is able to spatially resolve nearby stellar systems to reveal the detailed structures. To improve the sensitivity and scientific throughput, the CHARA array was funded by NSF-ATI in 2011, and by NSF-MRI in 2015, for an upgrade of adaptive optics (AO) systems to all six telescopes. The initial grant covers Phase I of the adaptive optics system, which includes an on-telescope Wavefront Sensor and non-common-path (NCP) error correction. The WFS use a fairly standard Shack-Hartman design and will initially close the tip tilt servo and log wavefront errors for use in data reduction and calibration. The second grant provides the funding for deformable mirrors for each telescope which will be used closed loop to remove atmospheric aberrations from the beams. There are then over twenty reflections after the WFS at the telescopes that bring the light several hundred meters into the beam combining laboratory. Some of these, including the delay line and beam reducing optics, are powered elements, and some of them, in particular the delay lines and telescope Coude optics, are continually moving. This means that the NCP problems in an interferometer are much greater than those found in more standard telescope systems. A second, slow AO system is required in the laboratory to correct for these NCP errors. We will breifly describe the AO system, and it's current status, as well as discuss the new science enabled by the system with a focus on our YSO program.

  17. Structural peculiarities dominate the turgor pressure response of the marine alga Valonia utricularis upon osmotic challenges.

    PubMed

    Heidecker, M; Mimietz, S; Wegner, L H; Zimmermann, U

    2003-03-15

    (-) induced an 'anomalous' hyposmotic turgor pressure response followed by the usual backregulation of pressure. After a 2-day preincubation in ASW(suc), significantly lower sigma(e) values were obtained both hyperosmotically (sigma(eNaCl) = 0.78 +/- 0.14; sigma(esuc) = 0.72 +/- 0.15) and hyposmotically (sigma(eNaCl) = 0.70 +/- 0.17; sigma(esuc) = 0.63 +/- 0.09), probably due to long-term effects on membrane structure to be elucidated yet. The freshwater alga Chara corallina lacked these apparently closely related structural and biophysical features of Valonia.

  18. Nutritional value of the Chilean seaweeds Cryptonemia obovata and Rhodymenia corallina.

    PubMed

    Ortiz, Jaime; Vivanco, Juan; Jiménez, Paula; Leiva, Moisés; Ramírez, Leslie; Bustamante, Andrés

    2010-10-01

    Some nutritional components of the edible seaweeds Cryptonemia obovata and Rhodymenia corallina were determined. The amino acid content ranged from 1.0 +/- 0.3 to 4174.2 +/- 14.2 mg 100 g(-1) dry wt in C. obovata and between 0.9 +/- 0.3 and 2657.0 +/- 13.5 mg 100 g(-1) dry wt in R. corallina. The most abundant fatty acid in C. obovata was palmitic acid, reaching a value of 36.5 +/- 0.2%, while in Rhodymenia corallina the main fatty acid was oleic acid, reaching a value of 24.7 +/- 0.07%. Both seaweeds showed an important content of EPA (C20:5omega3). In C. obovata, alpha-tocopherol was the principal tocol (138.5 +/- 4.9 mg kg(-1) lipid), while in R. corallina, it was gamma-tocotrienol (850.3 +/- 9.4 mg kg(-1) lipid). Furthermore, beta-carotene was the main carotenoid pigment found in C. obovata. PMID:21121265

  19. Combined effects of cadmium and zinc on growth, tolerance, and metal accumulation in Chara australis and enhanced phytoextraction using EDTA.

    PubMed

    Clabeaux, Bernadette L; Navarro, Divina A; Aga, Diana S; Bisson, Mary A

    2013-12-01

    Chara australis (R. Br.) is a macrophytic alga that can grow in and accumulate Cd from artificially contaminated sediments. We investigated the effects of Zn independently and in combination with Cd on C. australis growth, metal tolerance, and uptake. Plant growth was reduced at concentrations ≥ 75 mg Zn (kg soil)⁻¹. Zn also increased the concentration of glutathione in the plant, suggesting alleviation of stress. Phytotoxic effects were observed at ≥ 250 mg added Zn (kg soil)⁻¹. At 1.5mg Zn (kg soil)⁻¹, the rhizoid bioconcentration factor (BCF) was >1.0 for both Cd and Zn. This is a criterion for hyperaccumulator status, a commonly used benchmark for utility in remediation of contaminated soils by phytoextraction. There was no significant interaction between Cd and Zn on accumulation, indicating that Chara should be effective at phytoextraction of mixed heavy metal contamination in sediments. The effects of the chelator, ethylenediaminetetraacetic acid (EDTA), were also tested. Moderate levels of EDTA increased Cd and Zn accumulation in rhizoids and Cd BCF of shoots, enhancing Chara's potential in phytoremediation. This study demonstrates for the first time the potential of macroalgae to remove metals from sediments in aquatic systems that are contaminated with a mixture of metals.

  20. Combined effects of cadmium and zinc on growth, tolerance, and metal accumulation in Chara australis and enhanced phytoextraction using EDTA.

    PubMed

    Clabeaux, Bernadette L; Navarro, Divina A; Aga, Diana S; Bisson, Mary A

    2013-12-01

    Chara australis (R. Br.) is a macrophytic alga that can grow in and accumulate Cd from artificially contaminated sediments. We investigated the effects of Zn independently and in combination with Cd on C. australis growth, metal tolerance, and uptake. Plant growth was reduced at concentrations ≥ 75 mg Zn (kg soil)⁻¹. Zn also increased the concentration of glutathione in the plant, suggesting alleviation of stress. Phytotoxic effects were observed at ≥ 250 mg added Zn (kg soil)⁻¹. At 1.5mg Zn (kg soil)⁻¹, the rhizoid bioconcentration factor (BCF) was >1.0 for both Cd and Zn. This is a criterion for hyperaccumulator status, a commonly used benchmark for utility in remediation of contaminated soils by phytoextraction. There was no significant interaction between Cd and Zn on accumulation, indicating that Chara should be effective at phytoextraction of mixed heavy metal contamination in sediments. The effects of the chelator, ethylenediaminetetraacetic acid (EDTA), were also tested. Moderate levels of EDTA increased Cd and Zn accumulation in rhizoids and Cd BCF of shoots, enhancing Chara's potential in phytoremediation. This study demonstrates for the first time the potential of macroalgae to remove metals from sediments in aquatic systems that are contaminated with a mixture of metals. PMID:24035462

  1. Does calcite encrustation in Chara provide a phosphorus nutrient sink?

    PubMed

    Siong, Kian; Asaeda, Takashi

    2006-01-01

    We studied the effect of calcite encrustation in stoneworts (Chara spp.) on P cycling in an aquatic ecosystem. Sequential fractionation was performed to quantify P fractions of the internodes of calcified (Ca-CF) and uncalcified (UCa-CF) Chara fibrosa Agardh ex Bruzelius. Our results showed that Ca-CF was able to store more P and about 14 to 23% of total P in Ca-CF was co-precipitated with encrusted calcite, while only 2 to 3% was found in UCa-CF. Furthermore, in Ca-CF, an increased amount of total P did not result in a higher release of bioavailable water-soluble and sodium hydroxide-extractable P. Extracellular calcification in Chara enhanced nutrient sink for P, provided a further bottom-up control of phytoplankton, and should be regarded as a positive feedback in stabilizing Chara dominance in lakes.

  2. Elevated CO2 levels affect the activity of nitrate reductase and carbonic anhydrase in the calcifying rhodophyte Corallina officinalis.

    PubMed

    Hofmann, Laurie C; Straub, Sandra; Bischof, Kai

    2013-02-01

    The concentration of CO(2) in global surface ocean waters is increasing due to rising atmospheric CO(2) emissions, resulting in lower pH and a lower saturation state of carbonate ions. Such changes in seawater chemistry are expected to impact calcification in calcifying marine organisms. However, other physiological processes related to calcification might also be affected, including enzyme activity. In a mesocosm experiment, macroalgal communities were exposed to three CO(2) concentrations (380, 665, and 1486 µatm) to determine how the activity of two enzymes related to inorganic carbon uptake and nutrient assimilation in Corallina officinalis, an abundant calcifying rhodophyte, will be affected by elevated CO(2) concentrations. The activity of external carbonic anhydrase, an important enzyme functioning in macroalgal carbon-concentrating mechanisms, was inversely related to CO(2) concentration after long-term exposure (12 weeks). Nitrate reductase, the enzyme responsible for reduction of nitrate to nitrite, was stimulated by CO(2) and was highest in algae grown at 665 µatm CO(2). Nitrate and phosphate uptake rates were inversely related to CO(2), while ammonium uptake was unaffected, and the percentage of inorganic carbon in the algal skeleton decreased with increasing CO(2). The results indicate that the processes of inorganic carbon and nutrient uptake and assimilation are affected by elevated CO(2) due to changes in enzyme activity, which change the energy balance and physiological status of C. officinalis, therefore affecting its competitive interactions with other macroalgae. The ecological implications of the physiological changes in C. officinalis in response to elevated CO(2) are discussed.

  3. Elevated CO2 levels affect the activity of nitrate reductase and carbonic anhydrase in the calcifying rhodophyte Corallina officinalis.

    PubMed

    Hofmann, Laurie C; Straub, Sandra; Bischof, Kai

    2013-02-01

    The concentration of CO(2) in global surface ocean waters is increasing due to rising atmospheric CO(2) emissions, resulting in lower pH and a lower saturation state of carbonate ions. Such changes in seawater chemistry are expected to impact calcification in calcifying marine organisms. However, other physiological processes related to calcification might also be affected, including enzyme activity. In a mesocosm experiment, macroalgal communities were exposed to three CO(2) concentrations (380, 665, and 1486 µatm) to determine how the activity of two enzymes related to inorganic carbon uptake and nutrient assimilation in Corallina officinalis, an abundant calcifying rhodophyte, will be affected by elevated CO(2) concentrations. The activity of external carbonic anhydrase, an important enzyme functioning in macroalgal carbon-concentrating mechanisms, was inversely related to CO(2) concentration after long-term exposure (12 weeks). Nitrate reductase, the enzyme responsible for reduction of nitrate to nitrite, was stimulated by CO(2) and was highest in algae grown at 665 µatm CO(2). Nitrate and phosphate uptake rates were inversely related to CO(2), while ammonium uptake was unaffected, and the percentage of inorganic carbon in the algal skeleton decreased with increasing CO(2). The results indicate that the processes of inorganic carbon and nutrient uptake and assimilation are affected by elevated CO(2) due to changes in enzyme activity, which change the energy balance and physiological status of C. officinalis, therefore affecting its competitive interactions with other macroalgae. The ecological implications of the physiological changes in C. officinalis in response to elevated CO(2) are discussed. PMID:23314813

  4. Structural polarity in the Chara rhizoid: a reevaluation

    NASA Technical Reports Server (NTRS)

    Kiss, J. Z.; Staehelin, L. A.

    1993-01-01

    The Chara rhizoid is a useful model system to study gravitropism since all phases of gravitropism occur in a single cell. Despite years of study, a complete description of the distinctive ultrastructure of Chara rhizoids is not available. Therefore, in this paper, we reevaluate the ultrastructural features of vertically grown rhizoids, which have a structural polarity consisting of seven distinct zones. We also characterize the apical vesicles and the cell wall in these rhizoids by using antibodies against pectic polysaccharides. These studies demonstrate that the cell wall consists of two pectinaceous domains and that a distinct population of apical vesicles contain methyl esterified pectin.

  5. Biogas production experimental research using algae.

    PubMed

    Baltrėnas, Pranas; Misevičius, Antonas

    2015-01-01

    The current study is on the the use of macro-algae as feedstock for biogas production. Three types of macro-algae, Cladophora glomerata (CG), Chara fragilis (CF), and Spirogyra neglecta (SN), were chosen for this research. The experimental studies on biogas production were carried out with these algae in a batch bioreactor. In the bioreactor was maintained 35 ± 1°C temperature. The results showed that the most appropriate macro-algae for biogas production are Spirogyra neglecta (SN) and Cladophora glomerata (CG). The average amount of biogas obtained from the processing of SN - 0.23 m(3)/m(3)d, CG - 0.20 m(3)/m(3)d, and CF - 0.12 m(3)/m(3)d. Considering the concentration of methane obtained during the processing of SN and CG, which after eight days and until the end of the experiment exceeded 60%, it can be claimed that biogas produced using these algae is valuable. When processing CF, the concentration of methane reached the level of 50% only by the final day of the experiment, which indicates that this alga is less suitable for biogas production.

  6. Larvicidal algae.

    PubMed

    Marten, Gerald G

    2007-01-01

    Although most algae are nutritious food for mosquito larvae, some species kill the larvae when ingested in large quantities. Cyanobacteria (blue-green algae) that kill larvae do so by virtue of toxicity. While blue-green algae toxins may offer possibilities for delivery as larvicides, the toxicity of live blue-green algae does not seem consistent enough for live algae to be useful for mosquito control. Certain species of green algae in the order Chlorococcales kill larvae primarily because they are indigestible. Where these algae are abundant in nature, larvae consume them to the exclusion of other food and then starve. Under the right circumstances, it is possible to introduce indigestible algae into a breeding habitat so they become abundant enough to render it unsuitable for mosquito production. The algae can persist for years, even if the habitat dries periodically. The main limitation of indigestible algae lies in the fact that, under certain conditions, they may not replace all the nutritious algae in the habitat. More research on techniques to ensure complete replacement will be necessary before indigestible algae can go into operational use for mosquito control.

  7. DNA barcoding the genus Chara: molecular evidence recovers fewer taxa than the classical morphological approach.

    PubMed

    Schneider, Susanne C; Rodrigues, Anuar; Moe, Therese Fosholt; Ballot, Andreas

    2015-04-01

    Charophytes (Charales) are benthic algae with a complex morphology. They are vulnerable to ecosystem changes, such as eutrophication, and are red-listed in many countries. Accurate identification of Chara species is critical for understanding their diversity and for documenting changes in species distribution. Species delineation is, however, complicated, because of high phenotypic plasticity. We used barcodes of the ITS2, matK and rbcL regions to test if the distribution of barcode haplotypes among individuals is consistent with species boundaries as they are currently understood. The study included freshly collected and herbarium material of 91 specimens from 10 European countries, Canada and Argentina. Results showed that herbarium specimens are useful as a source of material for genetic analyses for aquatic plants like Chara. rbcL and matK had highest sequence recoverability, but rbcL had a somewhat lower discriminatory power than ITS2 and matK. The tree resulting from the concatenated data matrix grouped the samples into six main groups contrary to a traditional morphological approach that consisted of 14 different taxa. A large unresolved group consisted of C. intermedia, C. hispida, C. horrida, C. baltica, C. polyacantha, C. rudis, C. aculeolata, and C. corfuensis. A second unresolved group consisted of C. virgata and C. strigosa. The taxa within each of the unresolved groups shared identical barcode sequences on the 977 positions of the concatenated data matrix. The morphological differences of taxa within both unresolved groups include the number and length of spine cells, stipulodes, and bract cells. We suggest that these morphological traits have less taxonomic relevance than hitherto assumed. PMID:26986531

  8. Binding of chara Myosin globular tail domain to phospholipid vesicles.

    PubMed

    Nunokawa, Shun-Ya; Anan, Hiromi; Shimada, Kiyo; Hachikubo, You; Kashiyama, Taku; Ito, Kohji; Yamamoto, Keiichi

    2007-11-01

    Binding of Chara myosin globular tail domain to phospholipid vesicles was investigated quantitatively. It was found that the globular tail domain binds to vesicles made from acidic phospholipids but not to those made from neutral phospholipids. This binding was weakened at high KCl concentration, suggesting that the binding is electrostatic by nature. The dissociation constant for the binding of the globular tail domain to 20% phosphatidylserine vesicles (similar to endoplasmic reticulum in acidic phospholipid contents) at 150 mM KCl was 273 nM. The free energy change due to this binding calculated from the dissociation constant was -37.3 kJ mol(-1). Thus the bond between the globular tail domain and membrane phospholipids would not be broken when the motor domain of Chara myosin moves along the actin filament using the energy of ATP hydrolysis (DeltaG degrees ' = -30.5 kJ mol(-1)). Our results suggested that direct binding of Chara myosin to the endoplasmic reticulum membrane through the globular tail domain could work satisfactorily in Chara cytoplasmic streaming. We also suggest a possible regulatory mechanism of cytoplasmic streaming including phosphorylation-dependent dissociation of the globular tail domain from the endoplasmic reticulum membrane.

  9. Recent technical and scientific highlights from the CHARA Array

    NASA Astrophysics Data System (ADS)

    McAlister, Harold A.; ten Brummelaar, Theo A.; Ridgway, Stephen T.; Gies, Douglas R.; Sturmann, Judit; Sturmann, Laszlo; Turner, Nils H.; Schaefer, Gail H.; Boyajian, Tabetha S.; Farrington, Christopher D.; Goldfinger, P. J.; Webster, Larry

    2012-07-01

    The CHARA Array is a six-telescope optical/IR interferometer managed by the Center for High Angular Resolution Astronomy of Georgia State University and located at Mount Wilson Observatory in the San Gabriel Mountains overlooking Pasadena, California. The CHARA Array has the longest operational baselines in the world and has been in regular use for scientific observations since 2005. In this paper we give an update of instrumentation improvements, primarily focused on the beam combiner activity. The CHARA Array supports seven beam combiners: CHARA CLASSIC, a two-way high-sensitivity K/H/J band system; CLIMB, a three-way K/H/J open-air combiner; FLUOR, a two-way K-band high-precision system; MIRC, a four/six-way H/K-band imaging system; CHAMP, a six-way K-band fringe tracker; VEGA, a four-way visible light high spectral resolution system; and PAVO, a three-way visible light high sensitivity system. We also present an overview of science results obtained over the last few years, including some recent imaging results.

  10. Production of biodiesel from coastal macroalgae (Chara vulgaris) and optimization of process parameters using Box-Behnken design.

    PubMed

    Siddiqua, Shaila; Mamun, Abdullah Al; Enayetul Babar, Sheikh Md

    2015-01-01

    Renewable biodiesels are needed as an alternative to petroleum-derived transport fuels, which contribute to global warming and are of limited availability. Algae biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuels. This study introduces an integrated method for the production of biodiesel from Chara vulgaris algae collected from the coastal region of Bangladesh. The Box-Behnken design based on response surface methods (RSM) used as the statistical tool to optimize three variables for predicting the best performing conditions (calorific value and yield) of algae biodiesel. The three parameters for production condition were chloroform (X1), sodium chloride concentration (X2) and temperature (X3). Optimal conditions were estimated by the aid of statistical regression analysis and surface plot chart. The optimal condition of biodiesel production parameter for 12 g of dry algae biomass was observed to be 198 ml chloroform with 0.75 % sodium chloride at 65 °C temperature, where the calorific value of biodiesel is 9255.106 kcal/kg and yield 3.6 ml. PMID:26636008

  11. Different speciation for bromine in brown and red algae, revealed by in vivo X-ray absorption spectroscopic studies.

    PubMed

    Küpper, Frithjof C; Leblanc, Catherine; Meyer-Klaucke, Wolfram; Potin, Philippe; Feiters, Martin C

    2014-08-01

    Members of various algal lineages are known to be strong producers of atmospherically relevant halogen emissions, that is a consequence of their capability to store and metabolize halogens. This study uses a noninvasive, synchrotron-based technique, X-ray absorption spectroscopy, for addressing in vivo bromine speciation in the brown algae Ectocarpus siliculosus, Ascophyllum nodosum, and Fucus serratus, the red algae Gracilaria dura, G. gracilis, Chondrus crispus, Osmundea pinnatifida, Asparagopsis armata, Polysiphonia elongata, and Corallina officinalis, the diatom Thalassiosira rotula, the dinoflagellate Lingulodinium polyedrum and a natural phytoplankton sample. The results highlight a diversity of fundamentally different bromine storage modes: while most of the stramenopile representatives and the dinoflagellate store mostly bromide, there is evidence for Br incorporated in nonaromatic hydrocarbons in Thalassiosira. Red algae operate various organic bromine stores - including a possible precursor (by the haloform reaction) for bromoform in Asparagopsis and aromatically bound Br in Polysiphonia and Corallina. Large fractions of the bromine in the red algae G. dura and C. crispus and the brown alga F. serratus are present as Br(-) defects in solid KCl, similar to what was reported earlier for Laminaria parts. These results are discussed according to different defensive strategies that are used within algal taxa to cope with biotic or abiotic stresses. PMID:26988449

  12. Different speciation for bromine in brown and red algae, revealed by in vivo X-ray absorption spectroscopic studies.

    PubMed

    Küpper, Frithjof C; Leblanc, Catherine; Meyer-Klaucke, Wolfram; Potin, Philippe; Feiters, Martin C

    2014-08-01

    Members of various algal lineages are known to be strong producers of atmospherically relevant halogen emissions, that is a consequence of their capability to store and metabolize halogens. This study uses a noninvasive, synchrotron-based technique, X-ray absorption spectroscopy, for addressing in vivo bromine speciation in the brown algae Ectocarpus siliculosus, Ascophyllum nodosum, and Fucus serratus, the red algae Gracilaria dura, G. gracilis, Chondrus crispus, Osmundea pinnatifida, Asparagopsis armata, Polysiphonia elongata, and Corallina officinalis, the diatom Thalassiosira rotula, the dinoflagellate Lingulodinium polyedrum and a natural phytoplankton sample. The results highlight a diversity of fundamentally different bromine storage modes: while most of the stramenopile representatives and the dinoflagellate store mostly bromide, there is evidence for Br incorporated in nonaromatic hydrocarbons in Thalassiosira. Red algae operate various organic bromine stores - including a possible precursor (by the haloform reaction) for bromoform in Asparagopsis and aromatically bound Br in Polysiphonia and Corallina. Large fractions of the bromine in the red algae G. dura and C. crispus and the brown alga F. serratus are present as Br(-) defects in solid KCl, similar to what was reported earlier for Laminaria parts. These results are discussed according to different defensive strategies that are used within algal taxa to cope with biotic or abiotic stresses.

  13. Photosynthesis by protoplasm extruded from Chara and Nitella.

    PubMed

    TOLBERT, N E; ZILL, L P

    1954-05-20

    (a) Photosynthesis with protoplasm isolated from Chara or Nitella as measured by C(14) fixation has been obtained at a rate 12 to 15 per cent of that of the whole cells. (b) Photosynthesis by cut cells of Chara or Nitella with the vacuolar sap removed was at a rate comparable to that of the whole cells. (c) Both the protoplasm and the cut cells reduced CO(2) in the light to sucrose and hexose phosphates. Other products formed were also detected by paper chromatography. In contrast, dark controls fixed the C(14) into products associated with plant respiration. (d) An important difference in the products from the extruded protoplasm was the absence of C(14)-labelled pentoses or sedoheptulose which were formed, however, by the whole or cut cells. This suggests that the most sensitive site affected by disruption of the cells may be the steps involved in the regeneration of the "C-2 acceptor" for CO(2) fixation in photosynthesis.

  14. The cell walls of Chara aspera Willd. (Charophyta) vegetative cells.

    PubMed

    Nyberg, H; Saranpää, P

    1989-01-01

    The ultrastructure of the vegetative cell walls of the charophyte Chara aspera Willd was studied with TEM. Thallus cells, rhizoid bulbil and rhizoidal node cells were investigated. The internodal cells transverse walls contained plasmodesmata. The longitudinal walls of the internodal cells were uniform, fibrillar, with two thin structurally distinct layers with different structure facing the cytoplasm. The outermost layers of internodal, cortical and rhizoid bulbil cells were composed of randomly orientated fibrils. The longitudinal walls of the cortical cells were helicoidal in structure. In the rhizoid bulbil cell walls, six different layers could be distinguished, but their occurrence seemed to depend on the fixation, staining and cutting procedures. A middle lamella and osmophilic deposits were found in the wall between rhizoidal node cells. The cytoplasmic structure of the internodal and cortical cells was not found to differ from other species of Chara. Charasomes were observed only in cortical cells.

  15. Separated Fringe Packet Observations with the CHARA Array

    NASA Astrophysics Data System (ADS)

    Farrington, Christopher D.; ten Brummelaar, T. A.; Mason, B. D.; Hartkopf, W. I.; McAlister, H. A.; Raghavan, D.; Turner, N. H.; Sturmann, L.; Sturmann, J.; Ridgway, S. T.

    2010-01-01

    We present the modification of the orbits of several spectroscopic binarie and a completely new orbit for HD 198084, including data taken at the Center for High Angular Resolution Astronomy (CHARA) Array. These data were obtained using a modification of the little used technique of separated fringe packets (SFP). The accuracy of the SFP data surpasses that of data taken by speckle, but the technique is much more time and labor intensive. Additionally, using SFPs with the CHARA Array, it is possible to obtain separations below the detection range of speckle interferometry (>30mas) and above the range in "classic" long-baseline interferometry where fringes from a binary overlap and are no longer separated (<10mas). Using spectroscopic binary systems with published speckle orbits, we are able to test our new measurements against their ephemerides to calibrate the method as well as produce entirely new orbits for systems with no current astrometric observations. The CHARA Array, operated by Georgia State University, was built with funding provided by the National Science Foundation, Georgia State University, the W. M. Keck Foundation, and the David and Lucile Packard Foundation. This research is supported by the National Science Foundation under grant AST 0908253 as well as by funding from the office of the Dean of the College of Arts and Science at Georgia State University.

  16. Immunolocalization of integrin-like proteins in Arabidopsis and Chara

    NASA Technical Reports Server (NTRS)

    Katembe, W. J.; Swatzell, L. J.; Makaroff, C. A.; Kiss, J. Z.

    1997-01-01

    Integrins are a large family of integral plasma membrane proteins that link the extracellular matrix to the cytoskeleton in animal cells. As a first step in determining if integrin-like proteins are involved in gravitropic signal transduction pathways, we have used a polyclonal antibody against the chicken beta1 integrin subunit in western blot analyses and immunofluorescence microscopy to gain information on the size and location of these proteins in plants. Several different polypeptides are recognized by the anti-integrin antibody in roots and shoots of Arabidopsis and in the internodal cells and rhizoids of Chara. These cross-reactive polypeptides are associated with cellular membranes, a feature which is consistent with the known location of integrins in animal systems. In immunofluorescence studies of Arabidopsis roots, a strong signal was obtained from labeling integrin-like proteins in root cap cells, and there was little or no immunolabel in other regions of the root tip. While the antibody stained throughout Chara rhizoids, the highest density of immunolabel was at the tip. Thus, in both Arabidopsis roots and Chara rhizoids, the sites of gravity perception/transduction appear to be enriched in integrin-like molecules.

  17. The Study of Algae

    ERIC Educational Resources Information Center

    Rushforth, Samuel R.

    1977-01-01

    Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)

  18. The chloroplast genome sequence of Chara vulgaris sheds new light into the closest green algal relatives of land plants.

    PubMed

    Turmel, Monique; Otis, Christian; Lemieux, Claude

    2006-06-01

    The phylum Streptophyta comprises all land plants and six monophyletic groups of charophycean green algae (Mesostigmatales, Chlorokybales, Klebsormidiales, Zygnematales, Coleochaetales, and Charales). Phylogenetic analyses of four genes encoded in three cellular compartments suggest that the Charales are sister to land plants and that charophycean green algae evolved progressively toward an increasing cellular complexity. To validate this phylogenetic hypothesis and to understand how and when the highly conservative pattern displayed by land plant chloroplast DNAs (cpDNAs) originated in the Streptophyta, we have determined the complete chloroplast genome sequence (184,933 bp) of a representative of the Charales, Chara vulgaris, and compared this genome to those of Mesostigma (Mesostigmatales), Chlorokybus (Chlorokybales), Staurastrum and Zygnema (Zygnematales), Chaetosphaeridium (Coleochaetales), and selected land plants. The phylogenies we inferred from 76 cpDNA-encoded proteins and genes using various methods favor the hypothesis that the Charales diverged before the Coleochaetales and Zygnematales. The Zygnematales were identified as sister to land plants in the best tree topology (T1), whereas Chaetosphaeridium (T2) or a clade uniting the Zygnematales and Chaetosphaeridium (T3) occupied this position in alternative topologies. Chara remained at the same basal position in trees including more land plant taxa and inferred from 56 proteins/genes. Phylogenetic inference from gene order data yielded two most parsimonious trees displaying the T1 and T3 topologies. Analyses of additional structural cpDNA features (gene order, gene content, intron content, and indels in coding regions) provided better support for T1 than for the topology of the above-mentioned four-gene tree. Our structural analyses also revealed that many of the features conserved in land plant cpDNAs were inherited from their green algal ancestors. The intron content data predicted that at least 15

  19. [Allelopathic effects of Corallina pilulifera on red tide microalgae Heterosigma akashiwo].

    PubMed

    Wang, Ren-Jun; Tang, Xue-Xi; Sun, Jun-Hua

    2008-10-01

    Different concentration methanol-, acetone-, ether-, and chloroform extracts of Corallina pilulifera were used to study their growth inhibitory effects on red tide microalgae Heterosigma akashiwo. The results showed that methanol extract at relatively higher concentrations had the highest growth inhibitory activity and killed all H. akashiwo cells, while the other three kinds of organic solvent extracts had no apparent inhibitory effects, suggesting that the growth inhibitory substances in C. pilulifera had relatively high polarity. The methanol extract was partitioned to petroleum ether phase, ethyl acetate phase, butanol phase, and distilled water phase by liquid-liquid fractionation, and the bioassays on the activity of each fraction were carried out on H. akashiwo. It was found that petroleum ether phase and ethyl acetate phase had strong algicidal effects on H. akashiwo, suggesting that the fatty acids in C. pilulifera tissues might be one of the main allelochemicals.

  20. Microbispora corallina sp. nov., a new species of the genus Microbispora isolated from Thai soil.

    PubMed

    Nakajima, Y; Kitpreechavanich, V; Suzuki, K; Kudo, T

    1999-10-01

    Two actinomycete strains, DF-28 and DF-32T, were isolated from soil samples collected in a deciduous dipterocarp forest in Thailand. They produced longitudinally paired spores on the tips of short sporophores alternately branched from aerial hyphae, and the chemotaxonomic properties of the isolates were the same as those of members of the family Streptosporangiaceae. These phenotypic properties, together with the results of a phylogenetic analysis based on 16S rRNA gene sequences, indicated that these isolates should be assigned to the genus Microbispora. The two isolates showed more than 93% DNA relatedness to each other, but their relatedness to any previously described species of the genus Microbispora was only 45% or less. They were distinguishable from previously described Microbispora spp. by a combination of physiological and biochemical properties. Therefore, a new species is proposed for these strains, under the name Microbispora corallina sp. nov. The type strain is strain DF-32T (= JCM 10267T).

  1. Characteristics of light chains of Chara myosin revealed by immunological investigation.

    PubMed

    Kakei, Toshihito; Sumiyoshi, Hiroki; Higashi-Fujime, Sugie

    2012-01-01

    Chara myosin is plant myosin responsible for cytoplasmic streaming and moves actin filaments at 60 µm/s, which is the fastest of all myosins examined. The neck of the myosin molecule has usually mechanical and regulatory roles. The neck of Chara myosin is supposed to bind six light chains, but, at present, we have no knowledge about them. We found Ca⁺⁺-calmodulin activated Chara myosin motility and its actin-activated ATPase, and actually bound with the Chara myosin heavy chain, indicating calmodulin might be one of candidates for Chara myosin light chains. Antibody against essential light chain from Physarum myosin, and antibodies against Chara calmodulin and chicken myosin light chain from lens membranes reacted with 20 kDa and 18 kDa polypeptides of Chara myosin preparation, respectively. Correspondingly, column purified Chara myosin had light chains of 20 kDa, and 18 kDa with the molar ratio of 0.7 and 2.5 to the heavy chain, respectively.

  2. Chlorophyll fluorescence images demonstrate variable pathways in the effects of plasma membrane excitation on electron flow in chloroplasts of Chara cells.

    PubMed

    Krupenina, Natalia A; Bulychev, Alexander A; Schreiber, Ulrich

    2011-07-01

    Chlorophyll fluorescence Imaging and Microscopy PAM fluorometry were applied to study spatial dynamics of photosystem II quantum yield (ΔF/F'(m)) and non-photochemical quenching (NPQ) in resting and electrically stimulated Chara corallina cells in the absence and presence of the hydrophilic electron acceptor methyl viologen (MV) in the external medium. Electrical excitation of the plasma membrane temporarily enhanced the heterogeneity of photosynthetic patterns under physiological conditions (in the absence of MV), but irreversibly eliminated these patterns in the presence of MV. These findings suggest that the action potential (AP) of the excitable plant cell affects the spatial patterns of photosynthesis and chlorophyll fluorescence through different pathways operated in the absence and presence of MV. Based on the extent of NPQ as an indicator of MV-dependent electron flow, it is supposed that MV cannot permeate into the chloroplasts of photosynthetically active "acid cell regions" but gains an immediate access to the stroma of these chloroplasts after triggering of an AP. The AP-triggered MV-dependent non-photochemical quenching in the chloroplasts of acidic cell regions was routinely observed at 0.1 mM Ca(2+) in the medium but not at elevated (2 mM) external Ca(2+) concentration. The results are interpreted in terms of competition between two permeant divalent ion species, Ca(2+) and MV(2+), for their passage through the voltage-gated calcium channels of the plasma membrane. It is proposed that the herbicidal activity of MV in characean cells, here serving as model object, can be manipulated by triggering AP and varying Ca(2+) concentration in the environmental medium.

  3. Spatial coordination of chloroplast and plasma membrane activities in Chara cells and its disruption through inactivation of 14-3-3 proteins.

    PubMed

    Bulychev, A A; van den Wijngaard, P W J; de Boer, A H

    2005-01-01

    In Chara corallina cells exposed to continuous light, external pH (pH(o)) and photosystem II (PSII) photochemical yield show correlated banding patterns. Photosynthetic activity is low in cell regions producing alkaline zones and high in the acid regions. We addressed the question whether (and how) photosynthetic activity and plasma membrane (PM) H+-pumping and H+-conductance are coupled in the different bands. First, PM H+-pump activity was stimulated with fusicoccin. This resulted in a more acidic pH in the acid bands without disturbing the correlation of photosynthetic electron transport and H+ fluxes across the PM. Next, H+-pump activity was reduced through microinjection of a phosphorylated peptide matching the canonical 14-3-3 binding motif RSTpSTP in the acid cell region. Microinjection induced a rapid (~5 min) rise in pH(o) by ca. 1.0 unit near the injection site, whereas the injection of the non-phosphorylated peptide had no effect. This pH rise confirms the supposed inhibition of the H+-pump upon the detachment of 14-3-3 proteins from the H+-ATPase. However, the PSII yield in the cell regions corresponding to the new alkaline peak remained high, which violated the normal inverse relations between the pH(o) and PSII photochemical yield. We conclude that the injection of the competitive inhibitor of the H+-ATPase disrupts the balanced operation of PM H+-transport and photosynthetic electron flow and promotes electron flow through alternative pathways.

  4. Auxin and cytoskeletal organization in algae.

    PubMed

    Jin, Qiaojun; Scherp, Peter; Heimann, Kirsten; Hasenstein, Karl H

    2008-05-01

    Hormones affect growth and alter the cytoskeleton suggesting that hormones and the cytoskeleton interact with each other. The cytoskeleton of ancestral algae such as Chara showed similar sensitivity to auxin as higher plants, even in generative structures but the sensitivity differed between IAA and alpha-NAA and presumably other auxins. The ability of cells to elongate depends on microtubule organization during the transition from disorganized to perpendicular to longitudinal organization of the cytoskeleton. Because of the many functions of the cytoskeleton it is possible that its composition is influenced by selective gene expression and adaptation to growth regulators. Co-localization of microtubules and F-actin change at a high temporal and spatial scale. High resolution measurements of mRNA expression indicate rapid turnover that may affect the composition of the cytoskeleton.

  5. Field study of growth and calcification rates of three species of articulated coralline algae in British Columbia, Canada.

    PubMed

    Fisher, K; Martone, P T

    2014-04-01

    Ocean acidification caused by rising atmospheric CO₂ is predicted to negatively impact growth and calcification rates of coralline algae. Decreases in coralline abundance may have cascading effects on marine ecosystems and on carbon sequestration worldwide. In this study, we measured growth and calcification rates of three common species of articulated coralline algae (Bossiella plumosa, Calliarthron tuberculosum, and Corallina vancouveriensis) at an intertidal field site in British Columbia. Linear growth rates measured in the field were slow, although Bossiella grew significantly faster (0.22 cm mon⁻¹) than Calliarthron and Corallina (0.17 and 0.15 cm mon⁻¹, respectively). Growth rates in the field were generally slower than growth rates in the laboratory, suggesting that data generated in the laboratory may not be representative of natural field conditions. Growth rates did not decrease as fronds approached their maximum observed size, suggesting that maximum frond size might be determined not by intrinsic factors but by external factors such as wave-induced drag forces. Using growth data, we estimate that the largest observed Bossiella frond (20 cm²) and Calliarthron frond (40 cm²) were about 4- and 11-years-old, respectively, and had deposited approximately 1 and 6 g CaCO₃ in that time. Given the great abundance of coralline algae along the coast of British Columbia, deposition rates of CaCO₃ are expected to play a significant but poorly characterized role in carbon sequestration.

  6. Membrane stretching triggers mechanosensitive Ca2+ channel activation in Chara.

    PubMed

    Kaneko, Toshiyuki; Takahashi, Naoya; Kikuyama, Munehiro

    2009-03-01

    In order to confirm that mechanosensitive Ca(2+) channels are activated by membrane stretching, we stretched or compressed the plasma membrane of Chara by applying osmotic shrinkage or swelling of the cell by varying the osmotic potential of the bathing medium. Aequorin studies revealed that treatments causing membrane stretching induced a transient but large increase in cytoplasmic concentration of Ca(2+) (Delta[Ca(2+)](c)). However, the observed Delta[Ca(2+)](c) decreased during the treatments, resulting in membrane compression. A second experiment was carried out to study the relationship between changes in membrane potential (DeltaE(m)) and stretching or compression of the plasma membrane. Significant DeltaE(m) values, often accompanied by an action potential, were observed during the initial exchange of the bathing medium from a hypotonic medium to a hypertonic one (plasmolysis). DeltaE(m) appears to be triggered by a partial stretching of the membrane as it was peeled from the cell wall. After plasmolysis, other exchanges from hypertonic to hypotonic media, with their accompanying membrane stretching, always induced large DeltaE(m) values and were often accompanied by an action potential. By contrast, action potentials were scarcely observed during other exchanges from hypotonic to hypertonic solutions (=membrane compression). Thus, we concluded that activation of the mechanosensitive channels is triggered by membrane stretching in Chara.

  7. Membrane stretching triggers mechanosensitive Ca2+ channel activation in Chara.

    PubMed

    Kaneko, Toshiyuki; Takahashi, Naoya; Kikuyama, Munehiro

    2009-03-01

    In order to confirm that mechanosensitive Ca(2+) channels are activated by membrane stretching, we stretched or compressed the plasma membrane of Chara by applying osmotic shrinkage or swelling of the cell by varying the osmotic potential of the bathing medium. Aequorin studies revealed that treatments causing membrane stretching induced a transient but large increase in cytoplasmic concentration of Ca(2+) (Delta[Ca(2+)](c)). However, the observed Delta[Ca(2+)](c) decreased during the treatments, resulting in membrane compression. A second experiment was carried out to study the relationship between changes in membrane potential (DeltaE(m)) and stretching or compression of the plasma membrane. Significant DeltaE(m) values, often accompanied by an action potential, were observed during the initial exchange of the bathing medium from a hypotonic medium to a hypertonic one (plasmolysis). DeltaE(m) appears to be triggered by a partial stretching of the membrane as it was peeled from the cell wall. After plasmolysis, other exchanges from hypertonic to hypotonic media, with their accompanying membrane stretching, always induced large DeltaE(m) values and were often accompanied by an action potential. By contrast, action potentials were scarcely observed during other exchanges from hypotonic to hypertonic solutions (=membrane compression). Thus, we concluded that activation of the mechanosensitive channels is triggered by membrane stretching in Chara. PMID:19234734

  8. PHOTOSYNTHESIS BY PROTOPLASM EXTRUDED FROM CHARA AND NITELLA

    PubMed Central

    Tolbert, N. E.; Zill, L. P.

    1954-01-01

    (a) Photosynthesis with protoplasm isolated from Chara or Nitella as measured by C14 fixation has been obtained at a rate 12 to 15 per cent of that of the whole cells. (b) Photosynthesis by cut cells of Chara or Nitella with the vacuolar sap removed was at a rate comparable to that of the whole cells. (c) Both the protoplasm and the cut cells reduced CO2 in the light to sucrose and hexose phosphates. Other products formed were also detected by paper chromatography. In contrast, dark controls fixed the C14 into products associated with plant respiration. (d) An important difference in the products from the extruded protoplasm was the absence of C14-labelled pentoses or sedoheptulose which were formed, however, by the whole or cut cells. This suggests that the most sensitive site affected by disruption of the cells may be the steps involved in the regeneration of the "C-2 acceptor" for CO2 fixation in photosynthesis. PMID:13163358

  9. Review and latest news from the VEGA/CHARA facility

    NASA Astrophysics Data System (ADS)

    Nardetto, N.; Mourard, D.; Perraut, K.; Tallon-Bosc, I.; Meilland, A.; Stee, P.; Ligi, R.; Challouf, M.; Clausse, J.-M.; Berio, P.; Spang, A.

    2014-12-01

    The VEGA instrument located at the focus of the Center for High Angular Resolution Astronomy (CHARA) array in California is a collaborating project between the Lagrange laboratory in Nice, where it has been developed (Mourard et al. 2009, 2011), the IPAG (Grenoble) and CRAL (Lyon) laboratories, and the CHARA group at Mount Wilson Observatory. The outcome from this international collaboration is to provide to the community a visible spectro-interferometer with an unprecedented angular resolution of 0.3 milli-second of arc (mas) together with a spectral resolution of 5000 or 30000. With such an instrument it becomes possible to determine simultaneously the size and the kinematic of the photosphere and/or of the circumstellar environment of the star as a function of the wavelength, which basically means for each spectral channel in the continuum and/or within spectral lines (in Hα for instance). The only limitation is to get enough signal to noise ratio in each spectral channel. We can currently reach a limiting magnitude of 8 in visible in medium spectral resolution (5000) and 4.5 in high resolution (30000). In this proceeding, we illustrate the two main subjects studied with the VEGA instrument, namely (1) how angular diameters are useful to accurately derive the fundamental parameters of stars, (2) how the spectral resolution can allow to study the kinematical structure of stars or even to derive chromatic images of stellar objects.

  10. Expanding the Chara/fluor Hot Disks Survey

    NASA Astrophysics Data System (ADS)

    Mennesson, B.; Scott, N.; Ten Brummelaar, T.; Bryden, G.; Turner, N.; Absil, O.; Millan-Gabet, R.; Coude Du Foresto, V.; Augereau, J. C.; Ridgway, S.; Lebreton, J.; Marion, L.

    Little is presently known about the hot (>300 K) dust component of debris disks surrounding main sequence stars, similar to the zodiacal dust cloud found in the inner solar system. While extensive surveys have been carried out from space, the majority of detections have surprisingly come from the ground, where near infrared interferometric observations have recently revealed small ( 1%) resolved excesses around a dozen nearby main sequence stars. Most of these results have come from the CHARA array "FLUOR" instrument (Mt. Wilson, CA), which has demonstrated the best sensitivity worldwide so far for this type of studies, and has carried out an initial survey of 40 stars. In order to further understand the origin of this "hot dust phenomenon", we will extend this initial survey to a larger number of stars and lower excess detection limits, i.e. higher visibility accuracy providing higher contrast measurements. To this end, two major instrumental developments are underway at CHARA. The first one aims at improving FLUOR's sensitivity to a median K-band magnitude limit of 5 (making 200 targets available). The second development is based on a method that we recently developed for accurate (better than 0.1%) null depth measurements of stars, and that can be extended to regular interferometric visibility measurements.

  11. Programs and Perspectives of Visible Long Baseline Interferometry VEGA/CHARA

    NASA Astrophysics Data System (ADS)

    Mourard, D.; Nardetto, N.; Ligi, R.; Perraut, K.

    VEGA/CHARA is a visible spectro-interferometer installed on the CHARA Array at Mount Wilson Observatory. Combining high spectral resolution (6,000 or 30,000) and high angular resolution (0.3 mas), VEGA/CHARA opens a wide class of astrophysical topics in the stellar physics domain. Circumstellar environments and fundamental parameters with a high precision could be studied. We will present a review of recent results and discuss the programs currently engaged in the field of pulsating stars and more generally for the fundamental stellar parameters. Details could be found at http://www-n.oca.eu/vega/en/publications/index.htm.

  12. Immunogold evidence suggests that endoplasmic reticulum is the site of protamine-type protein synthesis and participates in translocation of these proteins into the nucleus during Chara vulgaris spermiogenesis.

    PubMed

    Popłonska, Katarzyna; Kwiatkowska, Maria; Wojtczak, Agnieszka; Polit, Justyna

    2009-03-01

    During spermiogenesis of an alga Chara vulgaris, which in many aspects resembles that of animals, histones are replaced by protamine-type proteins. Our earlier immunocytochemical studies showed that this replacement started during the short stage V of spermiogenesis, when electronograms revealed an extensive system of cisternae and vesicles of endoplasmic reticulum (ER). The present studies revealed at stage V intensive incorporation of labeled (3)H-arginine and (3)H-lysine quickly translocating into a nucleus visualized with pulse-chase autoradiography of semithin sections. The immunogold technique with the use of the antibodies to protamine-type proteins isolated from Chara tomentosa show that both ER cisternae and vesicles are labeled with gold grains, which are absent from the spermatids not treated with the antibodies; thus, the ER is probably the site of the protamine-type protein synthesis. These proteins then are translocated to a nucleus through ER channels connected with the nuclear envelope, as suggested by gold labeling of an inner membrane of the nuclear envelope adjacent to condensed chromatin. The above results correspond with those of other authors showing that in animals, protamines bind with lamin B receptors localized in the inner membrane of the nuclear envelope. A hypothesis has been put forward that during Chara spermiogenesis the inner membrane of the nuclear envelope invaginates into a nucleus together with protamine-type proteins, which become separated from the membrane and penetrate into chromatin.

  13. [Allelopathic effect of Corallina pilulifera on Heterosigma akashiwo and its responses to UV-B irradiation].

    PubMed

    Zhao, Yan; Yu, Qing-Yun; Zhou, Bin; Ju, Qing; Tang, Xue-Xi

    2009-10-01

    By the method of co-culture and using cell density as the main indicator, this paper studied the allelopathic effect of Corallina pilulifera on Heterosigma akashiwo and its responses to UV-B irradiation. Under normal condition, the fresh tissue and aqueous extracts of C. pilulifera had significant inhibitory effects on the growth of H. akashiwo (P < 0.05), indicating their allopathic effect on H. akashiwo, while the dry power and culture media filtrate of C. pilulifera had less effect (P > 0.05). After pre-treated with different dose UV-B radiation and then co-cultured with H. akashiwo, C. pilulifera had some changes in the allelopathic activity of its fresh tissue, dry powder, and aqueous extracts. High-dose UV-B radiation (3.0 J x m(-2)) induced the decrease of the allelopathic effect, whereas low-dose UV-B radiation (0.9 J x m(-2)) was in adverse (P < 0.05).

  14. Exogenous melatonin affects photosynthesis in characeae Chara australis.

    PubMed

    Lazár, Dušan; Murch, Susan J; Beilby, Mary J; Al Khazaaly, Sabah

    2013-03-01

    Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general.

  15. Exogenous melatonin affects photosynthesis in characeae Chara australis.

    PubMed

    Lazár, Dušan; Murch, Susan J; Beilby, Mary J; Al Khazaaly, Sabah

    2013-03-01

    Melatonin was found in the fresh water characeae Chara australis. The concentrations (~4 μg/g of tissue) were similar in photosynthesizing cells, independent of their position on the plant and rhizoids (roots) without chloroplasts. Exogenous melatonin, added at 10 μM to the artificial pond water, increased quantum yield of photochemistry of photosystem II by 34%. The increased efficiency appears to be due to the amount of open reaction centers of photosystem II, rather than increased efficiency of each reaction center. More open reaction centers reflect better functionality of all photosynthetic transport chain constituents. We suggest that melatonin protection against reactive oxygen species covers not only chlorophyll, but also photosynthetic proteins in general. PMID:23299331

  16. Electrophysiology of turgor regulation in marine siphonous green algae.

    PubMed

    Bisson, M A; Beilby, M J; Shepherd, V A

    2006-05-01

    We review electrophysiological measures of turgor regulation in some siphonous green algae, primarily the giant-celled marine algae, Valonia and Ventricaria, with particular comparison to the well studied charophyte algae Chara and Lamprothamnium. The siphonous green algae have a less negative plasma membrane potential, and are unlikely to have a proton-based chemiosmotic transport system, dominated by active electrogenic K(+) uptake. We also make note of the unusual cellular structure of the siphonous green algae. Hypertonic stress, due to increased external osmotic pressure, is accompanied by positive-going potential difference (PD), increase in conductance, and slow turgor regulation. The relationship between these is not yet resolved, but may involve changes in K(+ )conductance (G (K)) or active K(+) transport at both membranes. Hypotonic turgor regulation, in response to decreased external osmotic pressure, is approximately 3 times faster than hypertonic turgor regulation. It is accompanied by a negative-going PD, although conductance also increases. The conductance increase and the magnitude of the PD change are strongly correlated with the magnitude of hypotonic stress.

  17. Interferometric Gravity Darkening Observations of Vega with the CHARA Array

    NASA Astrophysics Data System (ADS)

    Aufdenberg, J. P.; Merand, A.; Coude Foresto, V.; Absil, O.; Di Folco, E.; Kervella, P.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; ten Brummelaar, T. A.; Turner, N. H.; Berger, D. H.; McAlister, H. A.

    2005-12-01

    We have obtained high-precision interferometric measurements of the A0 V standard star Vega with the Center for High Angular Resolution Astronomy (CHARA) Array and the Fiber Linked Unit for Optical Recombination (FLUOR) beam combiner in the K' band at projected baselines between 103 m and 273 m. The measured squared visibility amplitudes beyond the first lobe are significantly weaker than expected for a slowly rotating star and provide strong evidence for the model of Vega as a rapidly rotating star viewed very nearly pole on. We have constructed a Roche-von Zeipel gravity-darkened model atmosphere which is in generally good agreement with both our interferometric data and archival spectrophotometry. Our model indicates Vega is rotating at ˜92% of its angular break-up rate with an equatorial velocity of ˜275 km s-1. We find a polar effective temperature of ˜10150 K and a pole-to-equator effective temperature difference of ˜2500 K, much larger than the ˜300 K derived by Gulliver, Hill, and Adelman. Our model suggests that Vega's cool equatorial atmosphere may have significant convective flux and predicts a significantly cooler spectral energy distribution for Vega as seen by its surrounding debris disk. This work was performed in part under contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Michelson Fellowship Program. JPL is managed for NASA by the California Institute of Technology. The CHARA Array is operated by the Center for High Angular Resolution Astronomy with support from Georgia State University and the National Science Foundation, the Keck Foundation and the Packard Foundation.

  18. Unique charge distribution in surface loops confers high velocity on the fast motor protein Chara myosin.

    PubMed

    Ito, Kohji; Yamaguchi, Yukie; Yanase, Kenji; Ichikawa, Yousuke; Yamamoto, Keiichi

    2009-12-22

    Most myosins have a positively charged loop 2 with a cluster of lysine residues that bind to the negatively charged N-terminal segment of actin. However, the net charge of loop 2 of very fast Chara myosin is zero and there is no lysine cluster in it. In contrast, Chara myosin has a highly positively charged loop 3. To elucidate the role of these unique surface loops of Chara myosin in its high velocity and high actin-activated ATPase activity, we have undertaken mutational analysis using recombinant Chara myosin motor domain. It was found that net positive charge in loop 3 affected V(max) and K(app) of actin activated ATPase activity, while it affected the velocity only slightly. The net positive charge in loop 2 affected K(app) and the velocity, although it did not affect V(max). Our results suggested that Chara myosin has evolved to have highly positively charged loop 3 for its high ATPase activity and have less positively charged loop 2 for its high velocity. Since high positive charge in loop 3 and low positive charge in loop 2 seem to be one of the reasons for Chara myosin's high velocity, we manipulated charge contents in loops 2 and 3 of Dictyostelium myosin (class II). Removing positive charge from loop 2 and adding positive charge to loop 3 of Dictyostelium myosin made its velocity higher than that of the wild type, suggesting that the charge strategy in loops 2 and 3 is widely applicable.

  19. Biological treatment of a dye solution by Macroalgae Chara sp.: effect of operational parameters, intermediates identification and artificial neural network modeling.

    PubMed

    Khataee, A R; Dehghan, G; Ebadi, A; Zarei, M; Pourhassan, M

    2010-04-01

    The potential of a macroalgae Chara sp. was investigated as a viable biomaterial for biological treatment of Malachite Green (MG) solution. The effects of operational parameters such as temperature, pH, initial dye concentration, reaction time and amount of algae on biological decolorization efficiency were studied. Biological treatment of MG solution by live and dead algae was compared. The reusability and efficiency of the live algae in long-term repetitive operations were also examined. The batch experiments results revealed the ability of algal species in biological degradation of the dye. The biological degradation compounds formed in this process were analyzed by UV-Vis, FT-IR and GC-Mass techniques. The degradation pathway of MG was proposed based on the identified compounds. In addition, an artificial neural network model was developed to predict the biological degradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R(2)=0.970). The influence of each parameter on the variable studied was assessed, reaction time being the most significant factor, followed by temperature of the solution.

  20. An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants.

    PubMed

    Schmälzlin, Elmar; van Dongen, Joost T; Klimant, Ingo; Marmodée, Bettina; Steup, Martin; Fisahn, Joachim; Geigenberger, Peter; Löhmannsröben, Hans-Gerd

    2005-08-01

    A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen-sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong autofluorescence of the plant tissue. The method was established using photosynthesis-competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species.

  1. Occurrence of calreticulin during the exchange of nucleohistones into protamine-type proteins in Chara vulgaris spermiogenesis.

    PubMed

    Popłońska, Katarzyna

    2013-02-01

    During spermiogenesis of an alga Chara vulgaris, which resembles that of animals, nucleohistones are replaced by protamine-type proteins. This exchange takes place in a spermatid nucleus during the key V spermiogenesis stage, in which rough endoplasmic reticulum is the site of protamine-type protein synthesis and is also the pathway guiding the proteins to their destination, nucleus. In the present work, it was shown that a chaperon protein, calreticulin (CRT), abundantly present at this significant V stage of spermiogenesis in a few cellular compartments, i.e., a nucleus, lumen of cisternae, and vesicles of significantly swollen ER as well as outside these structures, e.g., in Golgi apparatus, could have taken part in the process of exchange of nuclear proteins. Colocalization of two proteins, protamine-type proteins, crucial for reproduction, and CRT, was especially visible in a nucleus, mainly on its peripheries where condensed chromatin was present. Localization of protamine-type proteins and CRT in nucleus is in agreement with our previous results showing that protamine-type proteins were twofold more labelled in the peripheral area in comparison to the nucleus center occupied by noncondensed chromatin. The role of CRT in the reproduction of both plants and animals is also discussed.

  2. A relA-dependent regulatory cascade for auto-induction of microbisporicin production in Microbispora corallina.

    PubMed

    Fernández-Martínez, Lorena T; Gomez-Escribano, Juan P; Bibb, Mervyn J

    2015-08-01

    Microbisporicin is a potent type I lantibiotic produced by the rare actinomycete Microbispora corallina that is in preclinical trials for the treatment of infections caused by methicillin-resistant isolates of Staphylococcus aureus (MRSA). Analysis of the gene cluster for the biosynthesis of microbisporicin, which contains two unique post-translationally modified residues (5-chlorotryptophan and 3, 4-dihydroxyproline), has revealed an unusual regulatory mechanism that involves a pathway-specific extracytoplasmic function sigma factor (MibX)/anti-sigma factor (MibW) complex and an additional transcriptional regulator MibR. A model for the regulation of microbisporicin biosynthesis derived from transcriptional, mutational and quantitative reverse transcription polymerase chain reaction analyses suggests that MibR, which contains a C-terminal DNA-binding domain found in the LuxR family of transcriptional activators, functions as an essential master regulator to trigger microbisporicin production while MibX and MibW induce feed-forward biosynthesis and producer immunity. Moreover, we demonstrate that initial expression of mibR, and thus microbisporicin production, is dependent on the ppGpp synthetase gene (relA) of M. corallina. In addition, we show that constitutive expression of either of the two positively acting regulatory genes, mibR or mibX, leads to precocious and enhanced microbisporicin production.

  3. A rel A‐dependent regulatory cascade for auto‐induction of microbisporicin production in M icrobispora corallina

    PubMed Central

    Fernández‐Martínez, Lorena T.; Gomez‐Escribano, Juan P.

    2015-01-01

    Summary Microbisporicin is a potent type I lantibiotic produced by the rare actinomycete M icrobispora corallina that is in preclinical trials for the treatment of infections caused by methicillin‐resistant isolates of S taphylococcus aureus (MRSA). Analysis of the gene cluster for the biosynthesis of microbisporicin, which contains two unique post‐translationally modified residues (5‐chlorotryptophan and 3, 4‐dihydroxyproline), has revealed an unusual regulatory mechanism that involves a pathway‐specific extracytoplasmic function sigma factor (MibX)/anti‐sigma factor (MibW) complex and an additional transcriptional regulator MibR. A model for the regulation of microbisporicin biosynthesis derived from transcriptional, mutational and quantitative reverse transcription polymerase chain reaction analyses suggests that MibR, which contains a C‐terminal DNA‐binding domain found in the LuxR family of transcriptional activators, functions as an essential master regulator to trigger microbisporicin production while MibX and MibW induce feed‐forward biosynthesis and producer immunity. Moreover, we demonstrate that initial expression of mib R, and thus microbisporicin production, is dependent on the ppGpp synthetase gene (relA) of M . corallina. In addition, we show that constitutive expression of either of the two positively acting regulatory genes, mib R or mib X, leads to precocious and enhanced microbisporicin production. PMID:25939852

  4. Metabolic pathway for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) formation in Nocardia corallina: inactivation of mutB by chromosomal integration of a kanamycin resistance gene.

    PubMed Central

    Valentin, H F; Dennis, D

    1996-01-01

    The gene encoding the large subunit of the methylmalonyl-coenzyme A (CoA) mutase in Nocardia corallina (mutBNc) was cloned. A 4.3-kbp BamHI fragment containing almost the entire mutBNc was identified by Southern hybridization experiments employing a digoxigenin-labeled probe deduced from mutB of Streptomyces cinnamonensis, mutBNc was interrupted by insertion of a kanamycin resistance gene block (mutB::kan or mutB::neo) and introduced into N. corallina to obtain mutB-negative strains by homologous recombination. Four of sixteen kanamycin-resistant clones occurred via double-crossover events and harbored only the interrupted mutBNc. These exhibited no growth on odd-chain fatty acids in the presence of kanamycin but exhibited wild-type growth on even-chain fatty acids, glucose, and succinate. Whereas the wild type of N. corallina accumulates a copolyester of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) containing more than 60 mol% 3HV from most carbon sources, mutB-negative strains accumulated poly(3HB-co-3HV) containing only 2 to 6 mol% 3HV. Methylmalonyl-CoA mutase activity was not found in these clones. Therefore, this study provides strong evidence that the majority of 3HV units in poly(3HB-co-3HV) accumulated by N. corallina are synthesized via the methylmalonyl-CoA pathway. PMID:8593043

  5. Voltage-gated calcium and Ca2+-activated chloride channels and Ca2+ transients: voltage-clamp studies of perfused and intact cells of Chara.

    PubMed

    Berestovsky, Genrikh N; Kataev, Anatoly A

    2005-11-01

    The voltage-clamp technique was used to study Ca(2+) and Cl(-) transient currents in the plasmalemma of tonoplast-free and intact Chara corallina cells. In tonoplast-free cells [perfused medium with ethylene glycol bis(2-aminoethyl ether)tetraacetic acid] long-term inward and outward currents through Ca channels consisted of two components: with and without time-dependent inactivation. The voltage dependence of the Ca channel activation ratio was found to be sigmoid-shaped, with about -140-mV activation threshold, reaching a plateau at V>50 mV. As the voltage increased, the characteristic activation time decreased from approximately 10(3) ms in the threshold region to approximately 10 ms in the positive region. The positive pulse-activated channels can then be completely deactivated, which is recorded by the Ca(2+) tail currents, at below-threshold negative voltages with millisecond-range time constants. This tail current is used for fast and brief Ca(2+) injection into tonoplast-free and intact cells, to activate the chloride channels by Ca(2+) . When cells are perfused with EDTA-containing medium in the presence of excess Mg(2+), this method of injection allows the free submembrane Ca(2+) concentration, [Ca(2+)](c), to be raised rapidly to several tens of micromoles per liter. Then a chloride component is recorded in the inward tail current, with the amplitude proportional to [see text]. When Ca(2+) is thus injected into an intact cell, it induces an inward current in the voltage-clamped plasmalemma, having activation-inactivation kinetics qualitatively resembling that in EDTA-perfused cells, but a considerably higher amplitude and duration (approximately 10 A m(-2) and tau(inact)~0.5 s at -200 mV). Analysis of our data and theoretical considerations indicate that the [Ca(2+)](c) rise during cell excitation is caused mainly by Ca(2+) entry through plasmalemma Ca channels rather than by Ca(2+) release from intracellular stores.

  6. Performances and first science results with the VEGA/CHARA visible instrument

    NASA Astrophysics Data System (ADS)

    Mourard, D.; Tallon, M.; Bério, Ph.; Bonneau, D.; Chesneau, O.; Clausse, J. M.; Delaa, O.; Nardetto, N.; Perraut, K.; Spang, A.; Stee, Ph.; Tallon-Bosc, I.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2010-07-01

    This paper presents the current status of the VEGA (Visible spEctroGraph and polArimeter) instrument installed at the coherent focus of the CHARA Array, Mount Wilson CA. Installed in september 2007, the first science programs have started during summer 2008 and first science results are now published. Dedicated to high angular (0.3mas) and high spectral (R=30000) astrophysical studies, VEGA main objectives are the study of circumstellar environments of hot active stars or interactive binary systems and a large palette of new programs dedicated to fundamental stellar parameters. We will present successively the main characteristics of the instrument and its current performances in the CHARA environment, a short summary of two science programs and finally we will develop some studies showing the potential and difficulties of the 3 telescopes mode of VEGA/CHARA.

  7. The Vividness of Visual Imagery Questionnaire: commentary on the Marks-Chara debate.

    PubMed

    McKelvie, S J

    1990-04-01

    The purpose of this article is to comment on a recent debate between Chara and Marks over the construct validity of the Vividness of Visual Imagery Questionnaire (VVIQ). Following a description of their positions, it is argued that, although some of Chara's logical criticisms merit attention, much of his empirical work is methodologically unsound. However, in view of the nature of construct validity itself, it is also suggested that Marks ought to specify more clearly his concept of imagery vividness so critical experimental predictions can be made.

  8. Microinjected magnetic beads induce curvature in Chara rhizoids

    NASA Astrophysics Data System (ADS)

    Scherp, P.; Hasenstein, K.

    The gravitropic response of the Chara rhizoid is based on the interaction between the statoliths and the actin network located in the rhizoid apex. The rhizoid represents a model system for the study of gravitropism, because its apical cell contains the gravity sensing and response mechanism. In order to study the function of the statoliths and the cytoskeleton, we supplemented the naturally occurring statoliths with magnetic beads. These beads can be moved by an external magnetic field and they can be coated to interact with the cytoskeleton. The magnetic beads (1μm diameter) were injected close to the tip of the rhizoid in the presence of an external osmoticum to offset turgor pressure. The injection caused the formation of a noticeable plug of dense material at the site of impalement. After a recovery period of ca. 2 - 4 hours, the whole plant was mounted on the rotatable stage of a custom- built horizontal microscope, equipped with a long-working distance objective and a video camera. This stage is designed to reorientate the cell and/or the injected beads. In order to study the effect of the displacement of magnetic beads, an external magnetic field was applied. This external field was capable of displacing the magnetic particles but did not affect the natural statoliths. Work is in progress to quantify the response, to study the effect of microinjection on wall formation, and utilize coating of the beads to investigate their possible interaction with the original statoliths and with the microfilament network. Supported by NASA grant NAG 2- 1423.

  9. Passive Proton Conductance Is the Major Reason for Membrane Depolarization and Conductance Increase in Chara buckellii in High-Salt Conditions.

    PubMed

    Yao, X.; Bisson, M. A.

    1993-09-01

    Chara buckellii G.O.A., a salt-tolerant alga, has a less negative membrane potential (Em) when cultured in saline medium (artificial Waldsea water) than when cultured in freshwater. The cell hyperpolarizes and membrane conductance (Gm) decreases when the external medium is changed from Waldsea control solution (WCS), a high-salt medium, to low-salt medium containing sufficient sorbitol to generate the same osmotic potential as WCS. Banding pattern and proton flux experiments show that C. buckellii has higher passive proton influx in the alkaline band in high-salt medium than in low-salt medium. Decrease of the passive proton influx by darkness or low external pH dramatically hyperpolarizes the membrane and decreases the conductance. The pH dependence curves of Em and Gm also indicate the existence of high passive proton conductance (GH) in C. buckellii. Ion substitution experiments show that Em and Gm of saltwater cells are not dependent on K+, Na+, Cl-, or SO42+. Mg2+ also affects Em and Gm, but its effect is probably on GH. We conclude that GH is the most important cause of the membrane depolarization and conductance increase in the saltwater alga C. buckellii.

  10. Magnetic separation of algae

    DOEpatents

    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.

  11. Enhancing the staggered fluctuations of an actin filament sliding on Chara myosin.

    PubMed

    Hatori, Kuniyuki; Okeno, Yusuke; Honda, Hajime; Shimada, Katsuhiko; Matsuno, Koichiro

    2004-06-01

    We examined both longitudinal and transversal fluctuations of displacements of an actin filament sliding upon Chara myosin molecules. Although the magnitude of transversal fluctuations remained rather independent of ATP concentration, the longitudinal ones were found to increase their magnitude as the concentration increased. In addition, the longitudinal fluctuations gradually increased as the sliding velocity of the filament increased.

  12. Cell and molecular biology of the fastest myosins.

    PubMed

    Higashi-Fujime, Sugie; Nakamura, Akio

    2009-01-01

    Chara myosin is a class XI plant myosin in green algae Chara corallina and responsible for fast cytoplasmic streaming. The Chara myosin exhibits the fastest sliding movement of F-actin at 60 mum/s as observed so far, 10-fold of the shortening speed of muscle. It has some distinct properties differing from those of muscle myosin. Although knowledge about Chara myosin is very limited at present, we have tried to elucidate functional bases of its characteristics by comparing with those of other myosins. In particular, we have built the putative atomic model of Chara myosin by using the homology-based modeling system and databases. Based on the putative structure of Chara myosin obtained, we have analyzed the relationship between structure and function of Chara myosin to understand its distinct properties from various aspects by referring to the accumulated knowledge on mechanochemical and structural properties of other classes of myosin, particularly animal and fungal myosin V. We will also discuss the functional significance of Chara myosin in a living cell.

  13. Photosynthesis-dependent formation of convoluted plasma membrane domains in Chara internodal cells is independent of chloroplast position.

    PubMed

    Foissner, Ilse; Sommer, Aniela; Hoeftberger, Margit

    2015-07-01

    The characean green alga Chara australis forms complex plasma membrane convolutions called charasomes when exposed to light. Charasomes are involved in local acidification of the surrounding medium which facilitates carbon uptake required for photosynthesis. They have hitherto been only described in the internodal cells and in close contact with the stationary chloroplasts. Here, we show that charasomes are not only present in the internodal cells of the main axis, side branches, and branchlets but that the plasma membranes of chloroplast-containing nodal cells, protonemata, and rhizoids are also able to invaginate into complex domains. Removal of chloroplasts by local irradiation with intense light revealed that charasomes can develop at chloroplast-free "windows" and that the resulting pH banding pattern is independent of chloroplast or window position. Charasomes were not detected along cell walls containing functional plasmodesmata. However, charasomes formed next to a smooth wound wall which was deposited onto the plasmodesmata-containing wall when the neighboring cell was damaged. In contrast, charasomes were rarely found at uneven, bulged wound walls which protrude into the streaming endoplasm and which were induced by ligation or puncturing. The results of this study show that charasome formation, although dependent on photosynthesis, does not require intimate contact with chloroplasts. Our data suggest further that the presence of plasmodesmata inhibits charasome formation and/or that exposure to the outer medium is a prerequisite for charasome formation. Finally, we hypothesize that the absence of charasomes at bulged wound walls is due to the disturbance of uniform laminar mass streaming. PMID:25524777

  14. Photosynthesis-dependent formation of convoluted plasma membrane domains in Chara internodal cells is independent of chloroplast position.

    PubMed

    Foissner, Ilse; Sommer, Aniela; Hoeftberger, Margit

    2015-07-01

    The characean green alga Chara australis forms complex plasma membrane convolutions called charasomes when exposed to light. Charasomes are involved in local acidification of the surrounding medium which facilitates carbon uptake required for photosynthesis. They have hitherto been only described in the internodal cells and in close contact with the stationary chloroplasts. Here, we show that charasomes are not only present in the internodal cells of the main axis, side branches, and branchlets but that the plasma membranes of chloroplast-containing nodal cells, protonemata, and rhizoids are also able to invaginate into complex domains. Removal of chloroplasts by local irradiation with intense light revealed that charasomes can develop at chloroplast-free "windows" and that the resulting pH banding pattern is independent of chloroplast or window position. Charasomes were not detected along cell walls containing functional plasmodesmata. However, charasomes formed next to a smooth wound wall which was deposited onto the plasmodesmata-containing wall when the neighboring cell was damaged. In contrast, charasomes were rarely found at uneven, bulged wound walls which protrude into the streaming endoplasm and which were induced by ligation or puncturing. The results of this study show that charasome formation, although dependent on photosynthesis, does not require intimate contact with chloroplasts. Our data suggest further that the presence of plasmodesmata inhibits charasome formation and/or that exposure to the outer medium is a prerequisite for charasome formation. Finally, we hypothesize that the absence of charasomes at bulged wound walls is due to the disturbance of uniform laminar mass streaming.

  15. Importance of the converter region for the motility of myosin as revealed by the studies on chimeric Chara myosins.

    PubMed

    Seki, Masaya; Kashiyama, Taku; Hachikubo, You; Ito, Kohji; Yamamoto, Keiichi

    2004-11-19

    A long alpha-helix in myosin head constitutes a lever arm together with light chains. It is known from X-ray crystallographic studies that the first three turns of this lever arm alpha-helix are inserted into the converter region of myosin. We previously showed that chimeric Chara myosin in which the motor domain of Chara myosin was connected to the lever arm alpha-helix of Dictyostelium myosin had motility far less than that expected for the motor domain of Chara myosin. Here, we replaced the inserted three turns of alpha-helix of Dictyostelium myosin with that of the Chara myosin and found that the replacement enhanced the motility 2.6-fold without changing the ATPase activity so much. The result clearly showed the importance of interaction between the converter region and the lever arm alpha-helix for the efficient motility of myosin.

  16. Epiphytic cyanobacteria on Chara vulgaris are the main contributors to N(2) fixation in rice fields.

    PubMed

    Ariosa, Yoanna; Quesada, Antonio; Aburto, Juan; Carrasco, David; Carreres, Ramón; Leganés, Francisco; Fernández Valiente, Eduardo

    2004-09-01

    The distribution of nitrogenase activity in the rice-soil system and the possible contribution of epiphytic cyanobacteria on rice plants and other macrophytes to this activity were studied in two locations in the rice fields of Valencia, Spain, in two consecutive crop seasons. The largest proportion of photodependent N(2) fixation was associated with the macrophyte Chara vulgaris in both years and at both locations. The nitrogen fixation rate associated with Chara always represented more than 45% of the global nitrogenase activity measured in the rice field. The estimated average N(2) fixation rate associated with Chara was 27.53 kg of N ha(-1) crop(-1). The mean estimated N(2) fixation rates for the other parts of the system for all sampling periods were as follows: soil, 4.07 kg of N ha(-1) crop(-1); submerged parts of rice plants, 3.93 kg of N ha(-1) crop(-1); and roots, 0.28 kg of N ha(-1) crop(-1). Micrographic studies revealed the presence of epiphytic cyanobacteria on the surface of Chara. Three-dimensional reconstructions by confocal scanning laser microscopy revealed no cyanobacterial cells inside the Chara structures. Quantification of epiphytic cyanobacteria by image analysis revealed that cyanobacteria were more abundant in nodes than in internodes (on average, cyanobacteria covered 8.4% +/- 4.4% and 6.2% +/- 5.0% of the surface area in the nodes and internodes, respectively). Epiphytic cyanobacteria were also quantified by using a fluorometer. This made it possible to discriminate which algal groups were the source of chlorophyll a. Chlorophyll a measurements confirmed that cyanobacteria were more abundant in nodes than in internodes (on average, the chlorophyll a concentrations were 17.2 +/- 28.0 and 4.0 +/- 3.8 microg mg [dry weight] of Chara(-1) in the nodes and internodes, respectively). These results indicate that this macrophyte, which is usually considered a weed in the context of rice cultivation, may help maintain soil N fertility in the rice

  17. Isoprenoid biosynthesis authenticates the classification of the green alga Mesostigma viride as an ancient streptophyte.

    PubMed

    Grauvogel, Carina; Petersen, Jörn

    2007-07-01

    Land plants harbor two essential and completely different metabolic pathways for isoprenoid synthesis. The cytosolic mevalonate pathway (MVA) is shared with heterotrophic eukaryotes, whereas the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway has a cyanobacterial origin and was recruited after primary endosymbiosis. Terrestrial plants and green algae have a common evolutionary ancestry, but biochemical as well as genome analyses indicate that the cytosolic MVA pathway is generally absent from Chlorophyta. We investigated the distribution of genes for both pathways in the green alga Mesostigma viride, a key species at the basis of streptophycean (charophycean green algae, land plant) evolution. Ten of altogether twelve generally weakly expressed genes for isoprenoid biosynthesis, including three for the cytosolic MVA pathway, were amplified using a reverse transcription PCR approach with individually designed degenerate primers. Two full length cDNA clones for the first enzyme of the MVA pathway (HMGS) were additionally established from the charophycean green alga Chara vulgaris by library screening. The presence of the MVA pathway in these advanced green algae indicates a universal distribution among Streptophyta, and our phylogenetic HMGS analyses substantiate the recent classification of Mesostigma basal to charophytes and land plants. We identified each of the five cytosolic MVA genes/cDNAs in the genome of the rhodophyte Galdieria sulphuraria and, furthermore, amplified four of them from the glaucophyte Cyanophora paradoxa. Our data indicate that the MVA pathway is a characteristic trait of Plantae in general and propose that it was specifically lost in a common ancestor of Chlorophyta.

  18. Membrane potential fluctuations in Chara australis: a characteristic signature of high external sodium.

    PubMed

    Al Khazaaly, Sabah; Alan Walker, N; Beilby, Mary Jane; Shepherd, Virginia A

    2009-12-01

    We have studied fluctuations in membrane PD in Chara australis at frequencies between 1 and 500 mHz, by classical noise analysis and by inspection of the PD time-course. The former shows (1) a quasi-Lorentzian (1/f (2)) rise of noise power as frequency falls, and (2) a marked increase in noise power when the cell is exposed to high salinity (Chara australis is a salt-sensitive species). The latter shows that, as well as initiating depolarization, exposure to 50 mM Na as either chloride or sulfate usually initiates a continuous but random series of small depolarizations which gives rise to the increase in noise and whose mechanism is discussed.

  19. Degradation of Proteins Artificially Introduced into Vacuoles of Chara australis1

    PubMed Central

    Moriyasu, Yuji; Tazawa, Masashi

    1988-01-01

    When an exogenous protein, bovine serum albumin, was introduced into the vacuole of a Chara australis internodal cell, it was degraded with time. This degradation proceeded only in the vacuole as far as could be observed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Degradation was inhibited by protease inhibitors such as antipain and leupeptin. Endogenous proteins introduced into the vacuole were also degraded there. Furthermore, intravacuolar cytoplasmic drops, which were often formed by cell ligation, seemed to be degraded in the vacuole. However, bovine serum albumin degradation did not proceed when mixed with isolated vacuolar sap. These results show that the vacuole in the Chara internodal cell has the capacity to degrade cellular proteins, but that cytoplasmic support is needed for this degrading activity to be maintained. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:16666427

  20. Jouvence of Fluor: Upgrades of a Fiber Beam Combiner at the CHARA Array

    NASA Astrophysics Data System (ADS)

    Scott, N. J.; Millan-Gabet, R.; Lhomé, E.; Ten Brummelaar, T. A.; Coudé Du Foresto, V.; Sturmann, J.; Sturmann, L.

    The FLUOR (Fiber Linked Unit for Optical Recombination) interferometric beam combiner located at the CHARA Array on Mt. Wilson, California has recently undergone a program of major upgrades known as Jouvence of FLUOR (JouFLU). These upgrades seek to improve the precision, use, and observing efficiency of FLUOR as well as introduce new modes of operation. A Fourier Transform Spectrograph (FTS) mode and a spectral dispersion mode have been added to improve calibration and data collection. New mechanized stages and new cameras have been added to FLUOR for alignment and pupil plane imaging. Entirely new control/command software has been written for FLUOR which brings it into compliance with CHARA software standards. This allows for continued software upgrades and full remote operation capability. The new JouFLU instrument is now operating on sky and is expected to achieve accurate interferometric visibility amplitude measurements with 0.1 to 0.3% precision.

  1. The Fast Rotating Star 51 Oph Probed by VEGA/CHARA

    NASA Astrophysics Data System (ADS)

    Jamialahmadi, N.; Berio, P.; Meilland, A.; Perraut, K.; Mourard, D.; Lopez, B.; Stee, P.; Nardetto, N.; Pichon, B.; Clausse, J. M.; Spang, A.; McAlister, H.; ten Brummelaar, T.

    2015-12-01

    Stellar rotation is a key in our understanding of both mass-loss and evolution of intermediate and massive stars. It can lead to anisotropic mass-loss in the form of radiative wind or an excretion disk. We used the VEGA visible beam combiner installed on the CHARA array that reaches a sub milliarcsecond resolution. We derived, for the first time, the extension and flattening of 51 Oph photosphere. We found an elongated ratio of 1.45 ± 0.12.

  2. Microanalytical identification of barium sulphate crystals in statoliths of Chara Rhizoids

    NASA Technical Reports Server (NTRS)

    Schroeter, K.; Lauchli, A.; Sievers, A. J.

    1979-01-01

    In contrast to higher plants, Chara rhizoids contain statolith vacuoles filled with biocrystallites of BaS04 in the form of rods composed of globular subunits ca. 7 nm in diameter. The revelation of the crystallites under electron microscopy is dependent on the fixative; best structural preservation was observed after fixation in a buffered glutaraldehyde + acrolein solution; 0s04 and KMnO4 partially dissolved both the biocrystallites and synthetic BaS04.

  3. [Moyse Charas, apothecary and medical doctor (Uzés 1619 - Paris 1698)].

    PubMed

    Felix, Fred W

    2002-01-01

    Some new information, based on many unedited documents is presented, in order to complete the biography of Moyse Charas, as published in this revue by Dorveaux (1929) and Bouvet (1949). The origin of the protestant family Charas lies in Pont-Saint-Espirt, from where the parents of Moyse Charas, passing Uzés, moved to Orange, where he took up the profession of apothecary and was declared Master by Frederick Henry, prince of Orange. Later, in Paris, he had contacts with the Dutch diplomat Constantijn Huygens and his son, the scientist Christiaan Huygens, and with the English physician and philosopher John Locke. After shorter visits to London and the Royal Society he lived there for a certain time, being called to contribute to cure King Charles II. He revisited Orange to get his promotion as a doctor of medicine. After having practised for some time in Holland he went to Spain for five years, as a physician of the embassy of the States General in Madrid and later in Galice. The last six months he suffered imprisonment by the Inquisition. Liberated after his conversion to Catholicism, he could finally return to Paris.

  4. Algae Derived Biofuel

    SciTech Connect

    Jahan, Kauser

    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.

  5. Cloning of the Nocardia corallina polyhydroxyalkanoate synthase gene and production of poly-(3-hydroxybutyrate-co-3-hydroxyhexanoate) and poly-(3-hydroxyvalerate-co-3-hydroxyheptanoate).

    PubMed

    Hall, B; Baldwin, J; Rhie, H G; Dennis, D

    1998-07-01

    The polyhydroxyalkanoate (PHA) synthase gene (phaCNc) from Nocardia corallina was identified in a lambda library on a 6-kb BamHI fragment. A 2.8-kb XhoII subfragment was found to contain the intact PHA synthase. This 2.8-kb fragment was subjected to DNA sequencing and was found to contain the coding region for the PHA synthase and a small downstream open reading frame of unknown function. On the basis of DNA sequence, phaCNc is closest in homology to the PHA synthases (phaCPaI and phaCPaII) of Pseudomonas aeruginosa (approximately 41% identity and 55% similarity). The 2.8-kb XhoII fragment containing phaCNc was subcloned into broad host range mobilizable plasmids and transferred into Escherichia coli, Klebsiella aerogenes (both containing a plasmid bearing phaA and phaB from Ralstonia eutropha), and PHA-negative strains of R. eutropha and Pseudomonas putida. The recombinant strains were grown on various carbon sources and the resulting polymers were analyzed. In these strains, the PHA synthase from N. corallina was able to mediate the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) containing high levels of 3-hydroxyhexanoate when grown on hexanoate and larger even-chain fatty acids and poly(3-hydroxyvalerate-co-3-hydroxyheptanoate) containing high levels of 3-hydroxyheptanoate when grown on heptanoate or larger odd-chain fatty acids.

  6. Blue-green algae

    MedlinePlus

    “Blue-green algae” describes a large and diverse group of simple, plant-like organisms found in salt water and some large fresh water lakes. Blue-green algae products are used for many conditions, but so ...

  7. GA3 content in young and mature antheridia of Chara tomentosa estimated by capillary electrophoresis.

    PubMed

    Kaźmierczak, Andrzej; Stepiński, Dariusz

    2005-01-01

    The content of gibberellic acid (GA3) in male sex organs of Chara tomentosa L. was estimated using capillary electrophoresis. Young antheridia contained 0.25 microg GA3 while mature ones 0.48 microg per antheridium. Although there are significant differences in GA3 content in antheridia between C. vulgaris and C. tomentosa, these values calculated per one spermatid are 2.4 and 3.3 pg, respectively. The present results compiled with the previous knowledge about regulation of GA3-dependent development of Characeae species allow an implication that the mechanisms controlling antheridia differentiation in both species can be similar.

  8. JouFLU: an upgraded FLUOR beam combiner at the CHARA Array

    NASA Astrophysics Data System (ADS)

    Lhomé, E.; Scott, N.; ten Brummelaar, T.; Mollier, B.; Reess, J. M.; Chapron, F.; Buey, T.; Sevin, A.; Sturmann, J.; Sturmann, L.; Coudé du Foresto, V.

    2012-07-01

    FLUOR, which has been operational on CHARA since 2002, is an infrared fiber beam combiner. The telescope array will soon be fitted with an adaptive optics system, which will enhance the interferometer performance. In this framework, FLUOR has been entirely redeveloped and will be able to measure visibilities with higher accuracy and better sensitivity. The technical upgrades consist of improving some existing systems and developing new features. The bench, which is now remotely operable, primarily offers spectral dispersion (long fringes scanning), a more sensitive camera and a Fourier Transform Spectrometer mode. This paper presents the detailed opto-mechanical design of JouFLU (FLUOR rejuvenation), and the current instrument status.

  9. Factors Affecting Development of Peroxisomes and Glycolate Metabolism among Algae of Different Evolutionary Lines of the Prasinophyceae.

    PubMed

    Kehlenbeck, P.; Goyal, A.; Tolbert, N. E.

    1995-12-01

    Leaf-type peroxisomes are not present in the primitive unicellular Prasinophycean line of algae but are present in the multicellular algae Mougeotia, Chara, and Nitella, which are in the one evolutionary line, Charophyceae, that led to higher plants. Processes related to glycolate metabolism that may have been modified or induced with the appearance of peroxisomes have been examined. The algal dissolved inorganic carbon-concentrating mechanism and alkalization of the medium during photosynthesis were not lost when peroxisomes appeared in the members of the Charophycean line of algae. Therefore, it is unlikely that lowering of the CO2 concentration in the environment was a major factor in the evolutionary appearance of peroxisomes. Multicellular Mougeotia, early members of the Charophycean line of algae, have peroxisomes, but they excrete excess glycolate into the medium. The cytosolic pyruvate reductase for D-lactate synthesis and the glycolate dehydrogenase activity almost disappeared when peroxisomal glycolate oxidase, which also oxidizes L-lactate, appeared. These biochemical changes do not indicate what caused the induction of leaf-type peroxisomes in this evolutionary line of algae. The oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and glycolate oxidase require about 200 to 400 [mu]M O2 for 0.5 Vmax. These high-O2-requiring steps in glycolate metabolism would have functioned faster with increasing atmospheric O2, which might have been the causative factor in the induction of peroxisomes.

  10. Growth towards light as an adaptation to high light conditions in Chara branches.

    PubMed

    Schneider, Susanne; Ziegler, Carmen; Melzer, Arnulf

    2006-01-01

    Growth of plants or plant organs towards more light is commonly interpreted as an adaptation to low light conditions. Here, we show for the first time, in a study of charophyte branches, a growth-based orientation towards light functioning as a mechanism to protect the plant from excessive light. Two Chara species were exposed to five different intensities of photosynthetically active radiation and species traits and pigmentation were measured. Branches of plants exposed to higher light intensities were convergent and pointed steeply upwards, whereas those exposed to lower light intensities grew nearly straight and were less inclined. Only branches that increased in length during the experiments reacted to differences in light intensity. This indicates that branch orientation is determined by a light-dependent growth reaction. Orientation of charophyte branches towards light is accompanied by a decrease in chlorophyll a (Chla) content and a lower Chla : carotenoid ratio, which clearly indicates that the plant is taking protective measures against potentially damaging excess light conditions. We suggest that the growth-based orientation of Chara branches towards light may protect sexual organs, which grow on adaxial branch sides, from light damage. In addition, the upward orientation of branches might lead to increased light transmission within dense charophyte beds, thus enabling an enhanced gross production.

  11. The response to gravity is correlated with the number of statoliths in Chara rhizoids

    NASA Technical Reports Server (NTRS)

    Kiss, J. Z.

    1994-01-01

    In contrast to higher plants, Chara rhizoids have single membrane-bound compartments that appear to function as statoliths. Rhizoids were generated by germinating zygotes of Chara in either soil water (SW) medium or artificial pond water (APW) medium. Differential-interference-contrast microscopy demonstrated that rhizoids form SW-grown plants typically contain 50 to 60 statoliths per cell, whereas rhizoids from APW-grown plants contain 5 to 10 statoliths per cell. Rhizoids from SW are more responsive to gravity than rhizoids from APW because (a) SW rhizoids were oriented to gravity during vertical growth, whereas APW rhizoids were relatively disoriented, and (b) curvature of SW rhizoids was 3 to 4 times greater throughout the time course of curvature. The growth rate of APW rhizoids was significantly greater than that of SW-grown rhizoids. This latter result suggests that APW rhizoids are not limited in their ability for gravitropic curvature by growth and that these rhizoids are impaired in the early stages of gravitropism (i.e. gravity perception). Plants grown in APW appeared to be healthy because of their growth rate and the vigorous cytoplasmic streaming observed in the rhizoids. This study is comparable to earlier studies of gravitropism in starch-deficient mutants of higher plants and provides support for the role of statoliths in gravity perception.

  12. The protonema of Chara fragilis Desv.: regenerative formation, photomorphogenesis, and gravitropism.

    PubMed

    Hodick, D

    1993-10-01

    When exposed to constant white light for four weeks, isolated nodes of Chara fragilis Desv. regenerated side branches, rhizoids, and multicellular protonemata, the latter being similar to those germinated from oospores. When kept in darkness the nodes developed protonemata exclusively. These were single-celled, colourless, and tip-growing and, with the light microscope, they looked like rhizoids. Upon exposure to blue light, but not to red or far-red, the growth rates of the protonemata rapidly declined, the cell apices swelled, and the nucleus migrated acropetally. Within 24 h the cells went through the first of a series of divisions resulting in the formation of multicellular protonemata. When returned to darkness after a blue light pulse of 5 h the cell divisions proceeded normally, but the protonemata showed etiolated growth. While growth of the internode was drastically promoted, the development of the multicellular apex and the lateral initial were suppressed. Both uni- and multicellular etiolating protonemata showed negative gravitropism but were phototropically, insensitive. It is argued that the single-celled protonema is an organ specialized for the penetration of mud covering the nodes or oospores of Chara and thus serves to search for light, comparable to etiolated hypocotyls and stems in seedlings of higher plants.

  13. A SEARCH FOR SEPARATED FRINGE PACKET BINARIES USING THE CHARA ARRAY

    SciTech Connect

    Raghavan, Deepak; McAlister, Harold A.; Farrington, Chris D.; Ten Brummelaar, Theo A.; Sturmann, Laszlo; Sturmann, Judit; Turner, Nils H.; Ridgway, Stephen T.

    2012-01-20

    We present the results of a comprehensive search for new companions to nearby solar-type stars using the separated fringe packet (SFP) technique at the Center for High Angular Resolution Astronomy (CHARA) Array. Our search included 636 observations of 186 stars, searching for companions with separations of approximately 8-80 mas and moderate brightness ratios ({Delta}K {approx}< 1.5). This survey was undertaken to support a comprehensive assessment of companions to solar-type stars within 25 pc. We detected separated fringe companions to two stars (HD 3196 and 79096) and found faint companion signatures to two more stars (HD 98231 and 137763). All of these companions are previously known by spectroscopic methods, and three of them have speckle interferometric observations as well. The faint companion seen to HD 98231 represents the first visual detection of this spectroscopic companion. Our null detection for new companions implies that the presumed gap between spectroscopic and visual techniques has largely been filled for nearby solar-type stars, thanks to systematic radial-velocity observations over multiple decades and a thorough coverage using visual techniques, especially speckle interferometric observations. We also generate simulated fringe packets to derive detection limits for SFP binaries using the CHARA Array.

  14. Vesicular trafficking in characean green algae and the possible involvement of a VAMP72-family protein.

    PubMed

    Hoepflinger, Marion; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2014-01-01

    The RAB5 GTPase ARA6 (AtARA6) of Arabidopsis thaliana is known to be involved in endosomal trafficking by targeting vesicles to the plasma membrane. During this process AtARA6 is working in close relationship with the SNARE protein VAMP727 (vesicle associated membrane protein 727). Recently, ARA6 of the characean green algae Chara australis (CaARA6) was shown to have properties similar to AtARA6, pointing to similar trafficking pathways. In order to gain further insight into the vesicle trafficking machinery of characeae, C. australis was analyzed for homologous proteins of the VAMP72-family. A CaVAMP72 protein was detected and classified by protein sequence alignment and phylogenetic analyses.

  15. Vesicular trafficking in characean green algae and the possible involvement of a VAMP72-family protein.

    PubMed

    Hoepflinger, Marion C; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2014-01-01

    The RAB5 GTPase ARA6 of Arabidopsis thaliana is known to be involved in endosomal trafficking by targeting vesicles to the plasma membrane. During this process AtARA6 is working in close relationship with the SNARE protein VAMP727 (vesicle associated membrane protein 727). Recently, ARA6 of the characean green algae Chara australis (CaARA6) was shown to have properties similar to AtARA6, pointing to similar trafficking pathways. In order to gain further insight into the vesicle trafficking machinery of Characeae, C. australis was analyzed for homologous proteins of the VAMP72-family. A CaVAMP72 protein was detected and classified by protein sequence alignment and phylogenetic analyses.

  16. Vesicular trafficking in characean green algae and the possible involvement of a VAMP72-family protein.

    PubMed

    Hoepflinger, Marion; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2014-01-01

    The RAB5 GTPase ARA6 (AtARA6) of Arabidopsis thaliana is known to be involved in endosomal trafficking by targeting vesicles to the plasma membrane. During this process AtARA6 is working in close relationship with the SNARE protein VAMP727 (vesicle associated membrane protein 727). Recently, ARA6 of the characean green algae Chara australis (CaARA6) was shown to have properties similar to AtARA6, pointing to similar trafficking pathways. In order to gain further insight into the vesicle trafficking machinery of characeae, C. australis was analyzed for homologous proteins of the VAMP72-family. A CaVAMP72 protein was detected and classified by protein sequence alignment and phylogenetic analyses. PMID:24614164

  17. Vesicular trafficking in characean green algae and the possible involvement of a VAMP72-family protein.

    PubMed

    Hoepflinger, Marion C; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2014-01-01

    The RAB5 GTPase ARA6 of Arabidopsis thaliana is known to be involved in endosomal trafficking by targeting vesicles to the plasma membrane. During this process AtARA6 is working in close relationship with the SNARE protein VAMP727 (vesicle associated membrane protein 727). Recently, ARA6 of the characean green algae Chara australis (CaARA6) was shown to have properties similar to AtARA6, pointing to similar trafficking pathways. In order to gain further insight into the vesicle trafficking machinery of Characeae, C. australis was analyzed for homologous proteins of the VAMP72-family. A CaVAMP72 protein was detected and classified by protein sequence alignment and phylogenetic analyses. PMID:25764429

  18. Transforming and oncogenic potential of activated c-Ha-ras in three immortalized human breast epithelial cell lines.

    PubMed

    Wang, B; Soule, H D; Miller, F R

    1997-01-01

    The ability of activated c-Ha-ras (codon 12 valine) to transform human breast epithelial cells varied for three different immortalized normal human breast epithelial cell lines established from two different women. Although activated c-Ha-ras may transform and induce a preneoplastic phenotype in MCF10A cells, activated c-Ha-ras was not sufficient to transform MCF10-2A cells. Only two of three MCF10-2A clones which expressed mutant p21 protein acquired the ability to form colonies in soft agar. When xenografted into nude beige mice, two MCF10-2A clones formed squamous carcinomas and one formed no lesions at all. The ability to form tumors did not correlate with growth in soft agar. All three activated c-Ha-ras-transfected clones of MCF-12A formed colonies in soft agar but only two produced squamous carcinomas in nude beige mice. Unlike activated c-Ha-ras-transfected MCF10A cells, none of the activated c-Ha-ras-transfected MCF10-2A or MCF-12A clones formed ducts in xenografts. Rather, initial xenograft lesions consisted of nests of cells with squamous differentiation. These observations illustrate that additional events are involved in the transformation and progression of human breast epithelial cells with activated c-Ha-ras.

  19. Clocks in algae.

    PubMed

    Noordally, Zeenat B; Millar, Andrew J

    2015-01-20

    As major contributors to global oxygen levels and producers of fatty acids, carotenoids, sterols, and phycocolloids, algae have significant ecological and commercial roles. Early algal models have contributed much to our understanding of circadian clocks at physiological and biochemical levels. The genetic and molecular approaches that identified clock components in other taxa have not been as widely applied to algae. We review results from seven species: the chlorophytes Chlamydomonas reinhardtii, Ostreococcus tauri, and Acetabularia spp.; the dinoflagellates Lingulodinium polyedrum and Symbiodinium spp.; the euglenozoa Euglena gracilis; and the red alga Cyanidioschyzon merolae. The relative simplicity, experimental tractability, and ecological and evolutionary diversity of algal systems may now make them particularly useful in integrating quantitative data from "omic" technologies (e.g., genomics, transcriptomics, metabolomics, and proteomics) with computational and mathematical methods.

  20. Heterotrimeric G proteins in green algae: an early innovation in the evolution of the plant lineage.

    PubMed

    Hackenberg, Dieter; Pandey, Sona

    2014-01-01

    Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophyaceaen green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:24614119

  1. Heterotrimeric G proteins in green algae: an early innovation in the evolution of the plant lineage.

    PubMed

    Hackenberg, Dieter; Pandey, Sona

    2014-01-01

    Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophyaceaen green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions.

  2. Electron tomographic characterization of a vacuolar reticulum and of six vesicle types that occupy different cytoplasmic domains in the apex of tip-growing Chara rhizoids.

    PubMed

    Limbach, Christoph; Staehelin, L Andrew; Sievers, Andreas; Braun, Markus

    2008-04-01

    We provide a 3D ultrastructural analysis of the membrane systems involved in tip growth of rhizoids of the green alga Chara. Electron tomography of cells preserved by high-pressure freeze fixation has enabled us to distinguish six different types of vesicles in the apical cytoplasm where the tip growth machinery is accommodated. The vesicle types are: dark and light secretory vesicles, plasma membrane-associated clathrin-coated vesicles (PM-CCVs), Spitzenkoerper-associated clathrin-coated vesicles (Sp-CCVs) and coated vesicles (Sp-CVs), and microvesicles. Each of these vesicle types exhibits a distinct distribution pattern, which provides insights into their possible function for tip growth. The PM-CCVs are confined to the cytoplasm adjacent to the apical plasma membrane. Within this space they are arranged in clusters often surrounding tubular plasma membrane invaginations from which CCVs bud. This suggests that endocytosis and membrane recycling are locally confined to specialized apical endocytosis sites. In contrast, exocytosis of secretory vesicles occurs over the entire membrane area of the apical dome. The Sp-CCVs and the Sp-CVs are associated with the aggregate of endoplasmic reticulum membranes in the center of the growth-organizing Spitzenkoerper complex. Here, Sp-CCVs are seen to bud from undefined tubular membranes. The subapical region of rhizoids contains a vacuolar reticulum that extends along the longitudinal cell axis and consists of large, vesicle-like segments interconnected by thin tubular domains. The tubular domains are encompassed by thin filamentous structures resembling dynamin spirals which could drive peristaltic movements of the vacuolar reticulum similar to those observed in fungal hyphae. The vacuolar reticulum appears to serve as a lytic compartment into which multivesicular bodies deliver their internal vesicles for molecular recycling and degradation.

  3. Artificial neural networks (ANN) approach for modeling of removal of Lanaset Red G on Chara contraria.

    PubMed

    Celekli, Abuzer; Geyik, Faruk

    2011-05-01

    A three-layer artificial neural network (ANN) was constructed to predict the removal efficiency of Lanaset Red (LR) G on Chara contraria based on 2304 experimental sets. The effects of operating variables (particle size, adsorbent dosage, pH regimes, dye concentration, and contact time) were studied to optimize the sorption conditions of this dye. The operating variables were used as the input to the constructed neural network to predict the dye uptake at any time as the output. This adsorbent was characterized by FTIR. Pseudo second-order model was also fitted to the experimental data. According to values of error analyses and determinations coefficient, the ANN was more appropriate to describe this adsorption process. Result of this model indicated that pH regimes had the highest importance effect (49%) on the dye uptake.

  4. Ion flux interaction with cytoplasmic streaming in branchlets of Chara australis.

    PubMed

    Babourina, Olga; Voltchanskii, Konstantin; Newman, Ian

    2004-12-01

    Both parts of the actin-myosin complex involved in cytoplasmic streaming could be regulated by mineral ions. The main goal of this study was to find a relationship between cyclosis and ion transport across the cell wall and plasma membrane. The transport of K(+) and Ca(2+) along pH bands in Chara branchlet internodal cells was characterized by using the MIFE system for non-invasive microelectrode measurement of ion fluxes. Branchlets formed acidic and alkaline bands with the pH ranging from 5 to 8. Different pH patterns were observed for different sides of the branchlets. Sides with cyclosis streaming acropetally generally showed greater variation in the profiles of pH and H(+) fluxes. Although a high correlation was not found between pH bands and Ca(2+) or K(+) fluxes, there was a positive correlation between Ca(2+) and K(+) fluxes themselves for both sides of the branchlets. Application of cytochalasin D, an inhibitor of cyclosis, had no immediate effect on pH and ion fluxes, however, the time of cyclosis cessation corresponded with a dramatic change in Ca(2+) and K(+) fluxes; pH profiles and H(+) fluxes were affected within 2 h. The evidence suggests that, in Chara branchlets, pH band formation and Gd(3+)-insensitive Ca(2+) transport systems are linked to the cyclosis machinery: (i) the pH band amplitude for the acropetally streaming side was larger than that for the basipetally streaming side; (ii) cessation of cytoplasmic streaming after cytochalasin D application resulted in changed pH banding profiles and H(+), Ca(2+) and K(+) fluxes; and (iii) the application of GdCl(3) or incubation in GdCl(3) solutions did not lead to the cessation of cytoplasmic streaming, although external Ca(2+) fluxes changed.

  5. Plasmodesmal changes are related to different developmental stages of antheridia of Chara species.

    PubMed

    Kwiatkowska, M

    2003-09-01

    During the development of the antheridia of Chara species, dynamic changes in the occurrence and ultrastructure of plasmodesmata are observed which are closely correlated to particular developmental phases and presumably regulate the morphogenetic events in the antheridia. The disappearance of plasmodesmata between shield cells and between shied cells and the basal cell leads to a cessation in symplasmic transport around the antheridum and determines its concentric or centrifugal character via centrally situated capitular cells. Unplugged plasmodesmata are present between fully synchronously developing antheridial filament cells and obviously coordinate the development of the cells. In the middle phase of spermiogenesis, rough endoplasmic reticulum in antheridial filaments passes uncompressed through wide plasmodesmata and provides an additional transport pathway for developmental control factors. Plugged plasmodesmata link cells of different types or cells of the same type which are at different phases of cell cycle and guarantee their individual development. The plugging of plasmodesmata is a reversible process that depends on the morphogenetic situation. Plasmodesmata connecting the basal cell and the subbasal cell as well as the basal cell and capitular cells are transformed successively from the simple into the complex type and might be the pathways for an import of gibberellins and nutrients into the strong sink tissues of the developing antheridium. There is a symplasmic connection between the antheridum and the thallus via a basal cell. Prior to the initiation of spermatozoid differentiation (spermiogenesis), plasmodesmata connecting the basal cell with a subbasal cell and the basal cell with capitular cells are spontaneously broken, resulting in symplasmic isolation of the antheridium that is probably a signal which triggers the induction of spermatozoid differentiation. Premature plasmolytically evoked symplasmic isolation of the antheridium leads to the

  6. Origin of the algae.

    PubMed

    Perasso, R; Baroin, A; Qu, L H; Bachellerie, J P; Adoutte, A

    1989-05-11

    Eukaryotic algae are traditionally separated into three broad divisions: the rhodophytes, the chromophytes and the chlorophytes. The evolutionary relationships between these groups, their links with other eukaryotes and with other photosynthetic groups, such as euglenophytes and cryptophytes, have been the subject of much debate and speculation. Here we analyse partial sequences of the large (28S) cytoplasmic ribosomal RNA from ten new species of protists belonging to various groups of unicellular algae. By combining them with the homologous sequences from 14 other unicellular and multicellular eukaryotes, we show that rhodophytes, chromophytes and chlorophytes emerge as three distinct groups late among eukaryotes, that is, close to the metazoa-metaphytes radiation. This implies a relatively late occurrence of eukaryotic photosynthetic symbiosis. We also provide details of intra- and inter-phyla relationships.

  7. Genomics of Volvocine Algae

    PubMed Central

    Umen, James G.; Olson, Bradley J.S.C.

    2015-01-01

    Volvocine algae are a group of chlorophytes that together comprise a unique model for evolutionary and developmental biology. The species Chlamydomonas reinhardtii and Volvox carteri represent extremes in morphological diversity within the Volvocine clade. Chlamydomonas is unicellular and reflects the ancestral state of the group, while Volvox is multicellular and has evolved numerous innovations including germ-soma differentiation, sexual dimorphism, and complex morphogenetic patterning. The Chlamydomonas genome sequence has shed light on several areas of eukaryotic cell biology, metabolism and evolution, while the Volvox genome sequence has enabled a comparison with Chlamydomonas that reveals some of the underlying changes that enabled its transition to multicellularity, but also underscores the subtlety of this transition. Many of the tools and resources are in place to further develop Volvocine algae as a model for evolutionary genomics. PMID:25883411

  8. Transforming activity of the c-Ha-ras oncogene having two point mutations in codons 12 and 61.

    PubMed

    Sekiya, T; Prassolov, V S; Fushimi, M; Nishimura, S

    1985-09-01

    A recombinant plasmid carrying the human c-Ha-ras gene with two point mutations in codons 12 and 61 was constructed and its transforming activity on mouse NIH 3T3 cells was compared with those of genes with a single mutation in either codon 12 or 61. Quantitative analyses revealed that the gene with two mutations had essentially the same transforming activity as the genes with single mutations. These results indicate that a single mutation of the c-Ha-ras gene in either codon 12 or 61 is sufficient to activate the gene and that neither of the two mutation sites involved in activation of the gene needs to be intact for transforming activity.

  9. Sodium efflux from perfused giant algal cells.

    PubMed

    Clint, G M; Macrobbie, E A

    1987-06-01

    Internodal cells of the giant alga Chara corallina were perfused internally to replace the native cytoplasm, tonoplast and vacuole with artificial cytoplasm. Sodium efflux from perfused cells, measured by including (22)Na in the perfusion media, was increased by increasing the internal sodium concentration and by decreasing the external pH, and was inhibited by external application of the renal diuretic amiloride. The sodium efflux was markedly ATP-dependent, with a 50-fold decrease in efflux observed after perfusion with media lacking ATP. Efflux in the presence of ATP was reduced by 33% by inclusion of 10 μM N,N'-dicyclohexylcarbodiimide in the perfusion medium. The membrane potential of the perfused cells approximated that of intact cells from the same culture. It is suggested that sodium efflux in perfused Chara cells proceeds via a secondary antiporter with protons, regulated by ATP in a catalytic role and with the proton motive force acting as the energy source.

  10. Miocene Coralline algae

    SciTech Connect

    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.

  11. Polar auxin transport: an early invention.

    PubMed

    Boot, Kees J M; Libbenga, Kees R; Hille, Sander C; Offringa, Remko; van Duijn, Bert

    2012-06-01

    In higher plants, cell-to-cell polar auxin transport (PAT) of the phytohormone auxin, indole-3-acetic acid (IAA), generates maxima and minima that direct growth and development. Although IAA is present in all plant phyla, PAT has only been detected in land plants, the earliest being the Bryophytes. Charophyta, a group of freshwater green algae, are among the first multicellular algae with a land plant-like phenotype and are ancestors to land plants. IAA has been detected in members of Charophyta, but its developmental role and the occurrence of PAT are unknown. We show that naphthylphthalamic acid (NPA)-sensitive PAT occurs in internodal cells of Chara corallina. The relatively high velocity (at least 4-5 cm/h) of auxin transport through the giant (3-5 cm) Chara cells does not occur by simple diffusion and is not sensitive to a specific cytoplasmic streaming inhibitor. The results demonstrate that PAT evolved early in multicellular plant life. The giant Chara cells provide a unique new model system to study PAT, as Chara allows the combining of real-time measurements and mathematical modelling with molecular, developmental, cellular, and electrophysiological studies.

  12. Heterotrimeric G-proteins in green algae. An early innovation in the evolution of the plant lineage.

    PubMed

    Hackenberg, Dieter; Pandey, Sona

    2014-01-01

    Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophycean green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions.

  13. Heterotrimeric G-proteins in green algae. An early innovation in the evolution of the plant lineage.

    PubMed

    Hackenberg, Dieter; Pandey, Sona

    2014-01-01

    Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophycean green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:25764428

  14. Fundamental Stellar Properties of M-Dwarfs from the CHARA Array

    NASA Astrophysics Data System (ADS)

    Berger, D. H.; Gies, D. R.; McAlister, H. A.; ten Brummelaar, T. A.; Henry, T. J.; Sturmann, J.; Sturmann, L.; Turner, N. H.; Ridgway, S. T.; Aufdenberg, J. P.; Mérand, A. M.

    2005-12-01

    We report the angular diameters of six M dwarfs ranging in spectral type from M1.0 V to M3.0 V measured with Georgia State University's CHARA Array, a long-baseline optical interferometer located at Mount Wilson Observatory. Observations were made with the longest baselines in the near infrared K'-band and yielded angular diameters less than one milliarcsecond. Using an iterative process combining parallaxes from the NStars program and photometrically-derived bolometric luminosities and masses, we calculated effective temperatures, surface gravities, and stellar radii. Our results are consistent with other empirical measurements of M-dwarf radii, but found that current models underestimate the true stellar radii by up to 15-20%. We suggest that theoretical models for low mass stars may be lacking an opacity source that alters the computed stellar radii. Science operations at the Array are supported by the National Science Foundation through NSF Grant AST--0307562 and by Georgia State University through the College of Arts and Sciences and the Office of the Vice President for Research. Financial support for DHB was provided by the National Science Foundation through grant AST--0205297.

  15. Zinc ions block H⁺/OH⁻ channels in Chara australis.

    PubMed

    Al Khazaaly, Sabah; Beilby, Mary J

    2012-08-01

    Chara australis cells exposed to media of pH 10 and above exhibit high conductance, arising from the opening of H⁺/OH⁻ channels in the plasma membrane. This high conductance can be totally inhibited by 1.0 mm ZnCl₂ and restored by 0.5 mm 2-mercaptoethanol (ME). Important for carbon fixation, H⁺/OH⁻ channels play a key role in cell pH banding. Banding was also shown to be abolished by 1.0 mm ZnCl₂ and restored in some cells by ME. The proton pump is also involved in banding, but was little affected by ZnCl₂ over the periods needed for the inhibition of H⁺/OH⁻ channels. Previously, we postulated that H⁺/OH⁻ channels open transiently at the onset of saline stress in salt-sensitive C. australis, causing membrane potential difference (PD) noise; and remain open in latter stages of saline stress, contributing to cell deterioration. ZnCl₂ totally inhibited the saline noise and the upwardly concave I/V characteristics associated with the putative H⁺/OH⁻ currents. Again, ME reversed both these effects. We discuss the mode of action of zinc ions and ME with reference to animal voltage-gated H⁺ channels and water channels.

  16. Separated Fringe Packet Observations with the CHARA Array. II. ω Andromeda, HD 178911, and ξ Cephei.

    NASA Astrophysics Data System (ADS)

    Farrington, C. D.; ten Brummelaar, T. A.; Mason, B. D.; Hartkopf, W. I.; Mourard, D.; Moravveji, E.; McAlister, H. A.; Turner, N. H.; Sturmann, L.; Sturmann, J.

    2014-09-01

    When observed with optical long-baseline interferometers, components of a binary star that are sufficiently separated produce their own interferometric fringe packets; these are referred to as separated fringe packet (SFP) binaries. These SFP binaries can overlap in angular separation with the regime of systems resolvable by speckle interferometry at single, large-aperture telescopes and can provide additional measurements for preliminary orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the undersampled regime between the bounds of spectroscopic surveys and speckle interferometry. In this process, a visibility calibration star is not needed, and the SFPs can provide an accurate vector separation. In this paper, we apply the SFP approach to ω Andromeda, HD 178911, and ξ Cephei with the CLIMB three-beam combiner at the CHARA Array. For these systems we determine component masses and parallax of 0.963 ± 0.049 M ⊙ and 0.860 ± 0.051 M ⊙ and 39.54 ± 1.85 mas for ω Andromeda, for HD 178911 of 0.802 ± 0.055 M ⊙ and 0.622 ± 0.053 M ⊙ with 28.26 ± 1.70 mas, and masses of 1.045 ± 0.031 M ⊙ and 0.408 ± 0.066 M ⊙ and 38.10 ± 2.81 mas for ξ Cephei.

  17. Separated Fringe Packet Binary Star Astrometry at the CHARA Array - An Update

    NASA Astrophysics Data System (ADS)

    Ten Brummelaar, Theo; Farrington, C. D.; Mason, B. D.; Roberts, L. C.; Turner, N. H.

    2014-01-01

    When observed with optical long-baseline interferometers (OLBI), components of a binary star which are sufficiently separated such that their interferometric fringe packets do not overlap are referred to as Separated Fringe Packet (SFP) binaries. At the CHARA Array these `wide' binaries are in the range of a few tens of milliarcseconds and extend out into the regime of systems resolved by speckle interferometry at single, large-aperture telescopes. These SFP measurements can provide additional data for orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the under-sampled regime between the bounds of spectroscopic surveys and speckle interferometry. Unlike binary stars whose fringes overlap, a visibility calibration star is not needed, and the separation of the fringe packets can provide an accurate vector separation. We apply the SFP approach to Omega Andromeda, HD 178911, and Xi Cephei. For these systems we determine masses for the two components of 0.963+/-0.049 M_{sun}; and 0.860+/-0.051 M_{sun}; and an orbital parallax of 39.54+/-1.85 mas for Omega Andromeda, for HD 178911 masses of 0.802+/-0.055 M_{sun}; and 0.622+/-0.053 M_{sun}; with orbital parallax of 28.26+/-1.70 mas, and masses of 1.045+/-0.031 M_{sun}; and 0.408+/-0.066 M_{sun}; orbital parallax of 38.10+/-2.81 mas for Xi Cephei.

  18. Salinity-induced noise in membrane potential of Characeae Chara australis: effect of exogenous melatonin.

    PubMed

    Beilby, Mary J; Al Khazaaly, Sabah; Bisson, Mary A

    2015-02-01

    Salt sensitive Characeae Chara australis responds to 50 mM NaCl by a prompt appearance of noise in the trans-membrane potential difference (PD). The noise diminishes with time in saline and PD depolarization, leading to altered current-voltage characteristics that could be modeled with H(+)/OH(-) channels. Beilby and Al Khazaaly (JMB 230:21-34, 2009) suggested that the noise might arise from cooperative transient opening of H(+)/OH(-) channels. Presoaking cells in 10 μM melatonin over 24 h abolished the noise in some cells, postponed its appearance in others or changed its characteristics. As melatonin is a very effective antioxidant, we postulated opening of H(+)/OH(-) channels by reactive oxygen species (ROS). Measurement of ROS using dihydrodichlorofluorescein diacetate confirmed substantial reduction in ROS production in melatonin-treated cells in saline and sorbitol media. However, ROS concentration decreased as a function of time in saline medium. Possible schemes for activation of H(+)/OH(-) channels under salinity stress are considered. PMID:25378124

  19. A Survey of Be Star Circumstellar Disks Using the CHARA Array Long Baseline Interferometer

    NASA Astrophysics Data System (ADS)

    Touhami, Y.; Gies, D. R.; Schaefer, G. H.; Richardson, N. D.; McAlister, H. A.; Ridgway, S. T.; ten Brummelaar, T. A.; Goldnger, P. J.; Sturmann, L.; Sturmann, J.; Turner, N. H.; Farrington, C. D.

    2012-12-01

    We present spatially resolved observations of circumstellar disks of 24 bright northern Be stars. The survey was performed with the CHARA Array interferometer in the K-band at intermediate and long baselines. The interferometric visibilities were fitted with a physical thick disk model where the disk gas density steeply decreases with radius. Physical and geometrical properties such as the density profile, the inclination and the position angles of the circumstellar disks were determined. We find that the disk density index varies between n ˜= 2.4-3.2, which is consistent with previous IRAS measurements. In addition to the interferometric observations, we have obtained simultaneous optical and near-IR spectrophotometry data taken at Lowell Observatory, and we show that the thick disk model reproduces well the disk IR flux excess detected spectrophotometrically. By combining the projected rotational velocity of the Be star with the disk inclination derived from interferometry, we were able to estimate the equatorial rotational velocities of our sample stars.

  20. IMAGING THE ALGOL TRIPLE SYSTEM IN THE H BAND WITH THE CHARA INTERFEROMETER

    SciTech Connect

    Baron, F.; Monnier, J. D.; Che, X.; Pedretti, E.; Zhao, M.; Schaefer, G.; Ten Brummelaar, T. A.; McAlister, H. A.; Farrington, C.; Sturmann, J.; Sturmann, L.; Turner, N.; Parks, R.; Thureau, N.; Ridgway, S. T.

    2012-06-10

    Algol ({beta} Per) is an extensively studied hierarchical triple system whose inner pair is a prototype semi-detached binary with mass transfer occurring from the sub-giant secondary to the main-sequence primary. We present here the results of our Algol observations made between 2006 and 2010 at the CHARA interferometer with the Michigan Infrared Combiner in the H-band. The use of four telescopes with long baselines allows us to achieve better than 0.5 mas resolution and to unambiguously resolve the three stars. The inner and outer orbital elements, as well as the angular sizes and mass ratios for the three components, are determined independently from previous studies. We report a significantly improved orbit for the inner stellar pair with the consequence of a 15% change in the primary mass compared with previous studies. We also determine the mutual inclination of the orbits to be much closer to perpendicularity than previously established. State-of-the-art image reconstruction algorithms are used to image the full triple system. In particular an image sequence of 55 distinct phases of the inner pair orbit is reconstructed, clearly showing the Roche-lobe-filling secondary revolving around the primary, with several epochs corresponding to the primary and secondary eclipses.

  1. Salinity-induced noise in membrane potential of Characeae Chara australis: effect of exogenous melatonin.

    PubMed

    Beilby, Mary J; Al Khazaaly, Sabah; Bisson, Mary A

    2015-02-01

    Salt sensitive Characeae Chara australis responds to 50 mM NaCl by a prompt appearance of noise in the trans-membrane potential difference (PD). The noise diminishes with time in saline and PD depolarization, leading to altered current-voltage characteristics that could be modeled with H(+)/OH(-) channels. Beilby and Al Khazaaly (JMB 230:21-34, 2009) suggested that the noise might arise from cooperative transient opening of H(+)/OH(-) channels. Presoaking cells in 10 μM melatonin over 24 h abolished the noise in some cells, postponed its appearance in others or changed its characteristics. As melatonin is a very effective antioxidant, we postulated opening of H(+)/OH(-) channels by reactive oxygen species (ROS). Measurement of ROS using dihydrodichlorofluorescein diacetate confirmed substantial reduction in ROS production in melatonin-treated cells in saline and sorbitol media. However, ROS concentration decreased as a function of time in saline medium. Possible schemes for activation of H(+)/OH(-) channels under salinity stress are considered.

  2. Measurements of eight early-type stars angular diameters using VEGA/CHARA interferometer

    NASA Astrophysics Data System (ADS)

    Challouf, M.; Nardetto, N.; Mourard, D.; Aroui, H.; Delaa, O.

    2014-12-01

    The surface brightness color (SBC) relation is an important tool to derive the distance of extragalatic eclipsing binaries. We determined the uniform disc angular diameter of the eight following early-type stars using VEGA/CHARA interferometric observations: θ_{UD}[δ Cyg] = 0.766 ± 0.047 mas, θ_{UD}[γ Lyr] = 0.742& ± 0.010 mas, θ_{UD}[γ Ori] = 0.701 ± 0.005 mas, θ_{UD}[ζ Peg] = 0.539 ± 0.009 mas, θ_{UD}[λ Aql] = 0.529 ± 0.003 mas, θ_{UD}[ζ Per] = 0.531 ± 0.007 mas, θ_{UD}[ι Her] = 0.304 ± 0.010 mas and θ_{UD}[8 Cyg] = 0.229 ± 0.011 mas (by extending V-K range from -0.76 to 0.02) with typical precision of about 1.5%. By combining these data with previous angular diameter determinations available in the literature, Challouf et al. (2014) provide for the very first time a SBC relation for early-type stars (-1≤V-K≤0) with a precision of about 0.16 magnitude or 7% in term of angular diameter (when using this SBC relation to derive the angular diameter of early-type stars).

  3. Separated fringe packet observations with the Chara Array. II. ω Andromeda, HD 178911, and ξ Cephei

    SciTech Connect

    Farrington, C. D.; Ten Brummelaar, T. A.; Turner, N. H.; Sturmann, L.; Sturmann, J.; Mason, B. D.; Hartkopf, W. I.; Mourard, D.; Moravveji, E.; McAlister, H. A. E-mail: theo@chara-array.org E-mail: sturmann@chara-array.org E-mail: bdm@usno.navy.mil E-mail: denis.mourard@oca.eu E-mail: hal@chara.gsu.edu

    2014-09-01

    When observed with optical long-baseline interferometers, components of a binary star that are sufficiently separated produce their own interferometric fringe packets; these are referred to as separated fringe packet (SFP) binaries. These SFP binaries can overlap in angular separation with the regime of systems resolvable by speckle interferometry at single, large-aperture telescopes and can provide additional measurements for preliminary orbits lacking good phase coverage, help constrain elements of already established orbits, and locate new binaries in the undersampled regime between the bounds of spectroscopic surveys and speckle interferometry. In this process, a visibility calibration star is not needed, and the SFPs can provide an accurate vector separation. In this paper, we apply the SFP approach to ω Andromeda, HD 178911, and ξ Cephei with the CLIMB three-beam combiner at the CHARA Array. For these systems we determine component masses and parallax of 0.963 ± 0.049 M {sub ☉} and 0.860 ± 0.051 M {sub ☉} and 39.54 ± 1.85 mas for ω Andromeda, for HD 178911 of 0.802 ± 0.055 M {sub ☉} and 0.622 ± 0.053 M {sub ☉} with 28.26 ± 1.70 mas, and masses of 1.045 ± 0.031 M {sub ☉} and 0.408 ± 0.066 M {sub ☉} and 38.10 ± 2.81 mas for ξ Cephei.

  4. [The union of three families of apothecaries in Paris in the 17th and 18th centuries--The apothecaries François Pihoué, François Regnault, Henry Charas and Marie Fourneau].

    PubMed

    Warolin, Christian

    2015-06-01

    The family network started with Marie Fourneau, daughter of the apothecary Jacques Fourneau, married successively two apothecaries first François Pihoué and then François Regnault and whose only daughter Marie Anne married the apothecary Henry Charas grandson of the famous apothecary Moyse Charas.

  5. [The union of three families of apothecaries in Paris in the 17th and 18th centuries--The apothecaries François Pihoué, François Regnault, Henry Charas and Marie Fourneau].

    PubMed

    Warolin, Christian

    2015-06-01

    The family network started with Marie Fourneau, daughter of the apothecary Jacques Fourneau, married successively two apothecaries first François Pihoué and then François Regnault and whose only daughter Marie Anne married the apothecary Henry Charas grandson of the famous apothecary Moyse Charas. PMID:26189312

  6. Effects of three macroalgae, Ulva linza (Chlorophyta), Corallina pilulifera (Rhodophyta) and Sargassum thunbergii (Phaeophyta) on the growth of the red tide microalga Prorocentrum donghaiense under laboratory conditions

    NASA Astrophysics Data System (ADS)

    Wang, Renjun; Xiao, Hui; Wang, You; Zhou, Wenli; Tang, Xuexi

    2007-10-01

    Allelopathic effects of several concentrations of fresh tissue and dry powder of three macroalgae, Ulva linza, Corallina pilulifera and Sargassum thunbergii, on the red tide microalga Prorocentrum donghaiense were evaluated in microcosms. Preliminary studies on the algicidal effects of one aqueous and four organic solvent extracts from the macroalgae on the microalga were carried out to confirm the existence of allelochemicals in the tissues of the macroalgae. The effects of macroalgal culture medium filtrate on P. donghaiense were investigated using initial or semi-continuous filtrate addition. Furthermore, the potential effects of the microalga on these three macroalgae were also tested. The results of the microcosm assay showed that the growth of P. donghaiense was strongly inhibited by using fresh tissues and dry powder of the three macroalgae. Both aqueous and methanol extracts of the macroalgae had strong growth inhibitory effects on P. donghaiense, while the other three organic solvent extracts (acetone, ether and chloroform) had no apparent effect on its growth; this suggested that the allelochemicals from these three macroalga had relatively high polarities. The three macroalgal culture medium filtrates exhibited apparent growth inhibitory effect on the microalgae under initial or semi-continuous addition, which suggested that the cells of P. donghaiense are sensitive to the allelochemicals. In contrast, P. donghaiense had no apparent effect on the growth of the macroalgae in coexistence experiment.

  7. Ecology of Harmful Algae

    NASA Astrophysics Data System (ADS)

    Roelke, Daniel L.

    2007-07-01

    Edna Graneli and Jefferson T. Turner, Editors;Ecological Studies Series, Vol. 189; Springer; ISBN 3540322094; 413 pp.; 2006; $195 Harmful algal blooms (HABs) affect commercially and recreationally important species, human health, and ecosystem functioning. Hallmark events are the visually stunning blooms where waters are discolored and filled with ichthyotoxin-producing algae that lead to large fish kills. Of most concern, however, are HABs that pose a threat to human health. For example, some phycotoxins bioaccumulate in the guts and tissues of commercially and recreationally important species that when consumed by humans, may result in nausea, paralysis, memory loss, and even death. In addition to the deleterious impacts of phycotoxins, HABs can be problematic in other ways. For example, the decay of blooms often leads to low dissolved oxygen in subsurface waters. Blooms also reduce light penetration into the water column. Both processes disrupt ecosystems and in some cases have completely destroyed benthic communities.

  8. Occurrence of arsenic species in algae and freshwater plants of an extreme arid region in northern Chile, the Loa River Basin.

    PubMed

    Pell, Albert; Márquez, Anna; López-Sánchez, José Fermín; Rubio, Roser; Barbero, Mercedes; Stegen, Susana; Queirolo, Fabrizio; Díaz-Palma, Paula

    2013-01-01

    This study reports data on arsenic speciation in two green algae species (Cladophora sp. and Chara sp.) and in five aquatic plants (Azolla sp., Myriophyllum aquaticum, Phylloscirpus cf. desserticola, Potamogeton pectinatus, Ruppia filifolia and Zannichellia palustris) from the Loa River Basin in the Atacama Desert (northern Chile). Arsenic content was measured by Mass spectrometry coupled with Inductively Coupled Plasma (ICP-MS), after acidic digestion. Liquid chromatography coupled to ICP-MS was used for arsenic speciation, using both anionic and cationic chromatographic exchange systems. Inorganic arsenic compounds were the main arsenic species measured in all samples. The main arsenic species in the extracts of freshwater algae and plants were arsenite and arsenate, whereas glycerol-arsenosugar (gly-sug), dimethylarsinic acid (DMA) and methylarsonic acid (MA) were present only as minor constituents. Of the samples studied, algae species accumulated more arsenic than aquatic plants. Total arsenic content ranged from 182 to 11100 and from 20 to 248 mg As kg(-1) (d.w.) in algae and freshwater plants, respectively. In comparison with As concentration in water samples, there was hyper-accumulation (>0.1% d.w.) in Cladophora sp.

  9. Fuel From Algae: Scaling and Commercialization of Algae Harvesting Technologies

    SciTech Connect

    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.

  10. [From algae to "functional foods"].

    PubMed

    Vadalà, M; Palmieri, B

    2015-01-01

    In the recent years, a growing interest for nutraceutical algae (tablets, capsules, drops) has been developed, due to their effective health benefits, as a potential alternative to the classic drugs. This review explores the use of cyanobacterium Spirulina, the microalgae Chlorella, Dunaliella, Haematococcus, and the macroalgae Klamath, Ascophyllum, Lithothamnion, Chondrus, Hundaria, Glacilaria, Laminaria, Asparagopsis, Eisenia, Sargassum as nutraceuticals and dietary supplements, in terms of production, nutritional components and evidence-based health benefits. Thus, our specific goals are: 1) Overview of the algae species currently used in nutraceuticals; 2) Description of their characteristics, action mechanisms, and possible side effects; 3) Perspective of specific algae clinical investigations development. PMID:26378764

  11. Transgenic algae engineered for higher performance

    SciTech Connect

    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.

  12. The role of H(+)/OH(-) channels in the salt stress response of Chara australis.

    PubMed

    Beilby, Mary J; Al Khazaaly, Sabah

    2009-07-01

    We investigate the electrophysiological salt stress response of the salt-sensitive charophyte Chara australis as a function of time in saline artificial pond water (saline APW) containing 50 mM NaCl and 0.1 mM CaCl(2). The effects are due to an increase in Na(+) concentration rather than an increase in Cl(-) concentration or medium osmolarity. A previous paper (Shepherd et al. Plant Cell Environ 31:1575-1591, 2008) described the rise in the background conductance and inhibition of proton pumping in saline APW in the first 60 min. Here we investigate the shift of membrane potential difference (PD) to levels above -100 mV and the change of shape of the current-voltage (I/V) profiles to upwardly concave. Arguing from thermodynamics, the I/V characteristics can be modeled by channels that conduct H(+) or OH(-). OH(-) was chosen, as H(+) required an unrealistic increase in the number/permeability of the channels at higher pH levels. Prolonged exposure to saline APW stimulated opening of more OH(-) channels. Recovery was still possible even at a PD near -50 mV, with partial return of proton pumping and a decrease in OH(-) current following APW wash. Upon change of pH from 7 to 9, the response was consistent with previously observed I/V characteristics of OH(-) channels. For a pH change to 6, the response was transient before channel closure but could still be modeled. The consequences of opening of H(+) or OH(-) channels while the cell is under salt stress are discussed.

  13. A CHARA ARRAY SURVEY OF CIRCUMSTELLAR DISKS AROUND NEARBY Be-TYPE STARS

    SciTech Connect

    Touhami, Y.; Gies, D. R.; McAlister, H. A.; Matson, R. E-mail: gies@chara.gsu.edu E-mail: rmatson@chara.gsu.edu; and others

    2013-05-10

    We report on a high angular resolution survey of circumstellar disks around 24 northern sky Be stars. The K-band continuum survey was made using the CHARA Array long baseline interferometer (baselines of 30-331 m). The interferometric visibilities were corrected for the flux contribution of stellar companions in those cases where the Be star is a member of a known binary or multiple system. For those targets with good (u, v) coverage, we used a four-parameter Gaussian elliptical disk model to fit the visibilities and to determine the axial ratio, position angle, K-band photospheric flux contribution, and angular diameter of the disk's major axis. For the other targets with relatively limited (u, v) coverage, we constrained the axial ratio, inclination angle, and/or disk position angle where necessary in order to resolve the degeneracy between possible model solutions. We also made fits of the ultraviolet and infrared spectral energy distributions (SEDs) to estimate the stellar angular diameter and infrared flux excess of each target. The mean ratio of the disk diameter (measured in K-band emission) to stellar diameter (from SED modeling) is 4.4 among the 14 cases where we reliably resolved the disk emission, a value which is generally lower than the disk size ratio measured in the higher opacity H{alpha} emission line. We estimated the equatorial rotational velocity from the projected rotational velocity and disk inclination for 12 stars, and most of these stars rotate close to or at the critical rotational velocity.

  14. The peculiar fast-rotating star 51 Ophiuchi probed by VEGA/CHARA

    NASA Astrophysics Data System (ADS)

    Jamialahmadi, N.; Berio, P.; Meilland, A.; Perraut, K.; Mourard, D.; Lopez, B.; Stee, P.; Nardetto, N.; Pichon, B.; Clausse, J. M.; Spang, A.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Vargas, N.; Scott, N.

    2015-07-01

    Context. Stellar rotation is a key in our understanding of both mass-loss and evolution of intermediate and massive stars. It can lead to anisotropic mass-loss in the form of radiative wind or an excretion disk. Aims: We wished to spatially resolve the photosphere and gaseous environment of 51 Oph, a peculiar star with a very high vsini of 267 km s-1 and an evolutionary status that remains unsettled. It has been classified by different authors as a Herbig, a β Pic, or a classical Be star. Methods: We used the VEGA visible beam combiner installed on the CHARA array that reaches a submilliarcsecond resolution. Observation were centered on the Hα emission line. Results: We derived, for the first time, the extension and flattening of 51 Oph photosphere. We found a major axis of θeq = 8.08 ± 0.70 R⊙ and a minor axis of θpol = 5.66 ± 0.23 R⊙. This high photosphere distortion shows that the star is rotating close to its critical velocity. Finally, using spectro-interferometric measurements in the Hα line, we constrained the circumstellar environment geometry and kinematics and showed that the emission is produced in a 5.2 ± 2 R⋆ disk in Keplerian rotation. Conclusions: From the visible point of view, 51 Oph presents all the features of a classical Be star: near critical-rotation and double-peaked Hα line in emission produced in a gaseous disk in Keplerian rotation. However, this does not explain the presence of dust as seen in the mid-infrared and millimeter spectra, and the evolutionary status of 51 Oph remains unsettled.

  15. THE CHARA ARRAY ANGULAR DIAMETER OF HR 8799 FAVORS PLANETARY MASSES FOR ITS IMAGED COMPANIONS

    SciTech Connect

    Baines, Ellyn K.; White, Russel J.; Jones, Jeremy; Boyajian, Tabetha; McAlister, Harold A.; Ten Brummelaar, Theo A.; Turner, Nils H.; Sturmann, Judit; Sturmann, Laszlo; Goldfinger, P. J.; Farrington, Christopher D.; Riedel, Adric R.; Huber, Daniel; Ireland, Michael; Von Braun, Kaspar; Ridgway, Stephen T.

    2012-12-10

    HR 8799 is an hF0 mA5 {gamma} Doradus-, {lambda} Bootis-, Vega-type star best known for hosting four directly imaged candidate planetary companions. Using the CHARA Array interferometer, we measure HR 8799's limb-darkened angular diameter to be 0.342 {+-} 0.008 mas (an error of only 2%). By combining our measurement with the star's parallax and photometry from the literature, we greatly improve upon previous estimates of its fundamental parameters, including stellar radius (1.44 {+-} 0.06 R{sub Sun }), effective temperature (7193 {+-} 87 K, consistent with F0), luminosity (5.05 {+-} 0.29 L{sub Sun }), and the extent of the habitable zone (HZ; 1.62-3.32 AU). These improved stellar properties permit much more precise comparisons with stellar evolutionary models, from which a mass and age can be determined, once the metallicity of the star is known. Considering the observational properties of other {lambda} Bootis stars and the indirect evidence for youth of HR 8799, we argue that the internal abundance, and what we refer to as the effective abundance, is most likely near solar. Finally, using the Yonsei-Yale evolutionary models with uniformly scaled solar-like abundances, we estimate HR 8799's mass and age considering two possibilities: 1.516{sup +0.038}{sub -0.024} M{sub Sun} and 33{sup +7}{sub -13.2} Myr if the star is contracting toward the zero-age main sequence or 1.513{sup +0.023}{sub -0.024} M{sub Sun} and 90{sup +381}{sub -50} Myr if it is expanding from it. This improved estimate of HR 8799's age with realistic uncertainties provides the best constraints to date on the masses of its orbiting companions, and strongly suggests they are indeed planets. They nevertheless all appear to orbit well outside the HZ of this young star.

  16. Two parthenogenetic populations of Chara canescens differ in their capacity to acclimate to irradiance and salinity.

    PubMed

    Schaible, Ralf; Gerloff-Elias, Antje; Colchero, Fernando; Schubert, Hendrik

    2012-02-01

    The parthenogens of Chara canescens (Charophyceae) occupy broader geographical and ecological ranges than their sexual counterparts. Two possible hypotheses explain the ubiquity of parthenogens: the occurrence of one or several parthenogens with wide niches, or of many parthenogens that are restricted to narrow ecological niches. For the purposes of this study, C. canescens individuals from two neighbouring populations of the Baltic Sea (Bodstedter Bodden = BB; Salzhaff = SH), which differed significantly in water transparency and salinity, were investigated for significant differences in physiological capacity. Individuals of both habitats acclimated quickly to daily changes in irradiances in the field, but the photosynthetic efficiency of PS II showed a significant decrease with increasing daily irradiance in the habitat BB, which has lower levels of salinity and water transparency. In addition to the field study, individuals were reared under different levels of environmental factors in the laboratory: four irradiances (70-600 μmol m(-2) s(-1)) and five salinity levels (0-24 psu). The individuals of both habitats grew almost equally well at intermediate salinity levels. Growth under the artificial light supply was highest at levels corresponding to the in situ conditions for each population. Total chlorophyll was highest at intermediate salinities (BB), or hardly changed with salinity (SH). The physiological capacity for individuals from SH clearly depends upon changing growth irradiance, whereas the capacity for individuals from BB was relatively independent of salinity and irradiance. These findings indicate that both parthenogenetic C. canescens populations are locally adapted to light. However, to test adaptive potential of the parthenogens, more than two populations should be tested in future.

  17. Algae fuel clean electricity generation

    SciTech Connect

    O'Sullivan, D.

    1993-02-08

    The paper describes plans for a 600-kW pilot generating unit, fueled by diesel and Chlorella, a green alga commonly seen growing on the surface of ponds. The plant contains Biocoil units in which Chlorella are grown using the liquid effluents from sewage treatment plants and dissolved carbon dioxide from exhaust gases from the combustion unit. The algae are partially dried and fed into the combustor where diesel fuel is used to maintain ignition. Diesel fuel is also used for start-up and as a backup fuel for seasonal shifts that affect the algae growing conditions. Since the algae use the carbon dioxide emitted during the combustion process, the process will not contribute to global warming.

  18. Seasonality of water chemistry, carbonate production, and biometric features of two species of Chara in a shallow clear water lake.

    PubMed

    Pukacz, Andrzej; Pełechaty, Mariusz; Frankowski, Marcin; Kowalski, Artur; Zwijacz-Koszałka, Kinga

    2014-01-01

    The objective of this study was to analyze the temporal variability of biometric features and the carbonate production of two charophytes: Chara polyacantha A. Braun and Chara rudis A. Braun against the background of the physical-chemical properties of water. The investigation was carried out in a small, mid-forest Lake Jasne (western Poland). It is a polymictic, mesotrophic, hardwater ecosystem dominated by charophyte vegetation. Each month, 10 individuals of each species were characterized in terms of morphometric features, fresh and dry weight, and the percentage of calcium carbonate. Additionally, physical-chemical parameters of the water were studied. The results of physical-chemical analyses indicated similar habitat conditions for both species. Despite smaller dry weight C. polyacantha was characterized by greater morphological variability and higher rates of growth and percentage share of calcium carbonate in dry mass than C. rudis. The percentage of calcium carbonates in dry mass did not differ significantly between the species and exceeded 60%, reaching the maximum (76% in C. polyacantha) in July and August. For both species, distinct correlations between the structure of biomass and morphological features were found. The obtained results show the great importance of charophyte vegetation in carbon cycling and functioning of lake ecosystems.

  19. Seasonality of water chemistry, carbonate production, and biometric features of two species of Chara in a shallow clear water lake.

    PubMed

    Pukacz, Andrzej; Pełechaty, Mariusz; Frankowski, Marcin; Kowalski, Artur; Zwijacz-Koszałka, Kinga

    2014-01-01

    The objective of this study was to analyze the temporal variability of biometric features and the carbonate production of two charophytes: Chara polyacantha A. Braun and Chara rudis A. Braun against the background of the physical-chemical properties of water. The investigation was carried out in a small, mid-forest Lake Jasne (western Poland). It is a polymictic, mesotrophic, hardwater ecosystem dominated by charophyte vegetation. Each month, 10 individuals of each species were characterized in terms of morphometric features, fresh and dry weight, and the percentage of calcium carbonate. Additionally, physical-chemical parameters of the water were studied. The results of physical-chemical analyses indicated similar habitat conditions for both species. Despite smaller dry weight C. polyacantha was characterized by greater morphological variability and higher rates of growth and percentage share of calcium carbonate in dry mass than C. rudis. The percentage of calcium carbonates in dry mass did not differ significantly between the species and exceeded 60%, reaching the maximum (76% in C. polyacantha) in July and August. For both species, distinct correlations between the structure of biomass and morphological features were found. The obtained results show the great importance of charophyte vegetation in carbon cycling and functioning of lake ecosystems. PMID:25401126

  20. Seasonality of Water Chemistry, Carbonate Production, and Biometric Features of Two Species of Chara in a Shallow Clear Water Lake

    PubMed Central

    Pełechaty, Mariusz; Kowalski, Artur; Zwijacz-Koszałka, Kinga

    2014-01-01

    The objective of this study was to analyze the temporal variability of biometric features and the carbonate production of two charophytes: Chara polyacantha A. Braun and Chara rudis A. Braun against the background of the physical-chemical properties of water. The investigation was carried out in a small, mid-forest Lake Jasne (western Poland). It is a polymictic, mesotrophic, hardwater ecosystem dominated by charophyte vegetation. Each month, 10 individuals of each species were characterized in terms of morphometric features, fresh and dry weight, and the percentage of calcium carbonate. Additionally, physical-chemical parameters of the water were studied. The results of physical-chemical analyses indicated similar habitat conditions for both species. Despite smaller dry weight C. polyacantha was characterized by greater morphological variability and higher rates of growth and percentage share of calcium carbonate in dry mass than C. rudis. The percentage of calcium carbonates in dry mass did not differ significantly between the species and exceeded 60%, reaching the maximum (76% in C. polyacantha) in July and August. For both species, distinct correlations between the structure of biomass and morphological features were found. The obtained results show the great importance of charophyte vegetation in carbon cycling and functioning of lake ecosystems. PMID:25401126

  1. [Moyse Charas, an apothecary, a physician, as well as the author of "Pharmacopée royale galénique et chymique". The study of his dynasty].

    PubMed

    Warolin, Christian

    2005-01-01

    New research works conducted at the Archives nationales led to the discovery of numerous documents related to Moyse Charas's progeny and made it possible to complete former studies. Presently the filiation of this famous family of Parisians apothecaries of the seventeenth and eighteenth centuries is well established. A family tree has been drawn up. PMID:16217892

  2. Centrifugation causes adaptation of microfilaments: studies on the transport of statoliths in gravity sensing Chara rhizoids.

    PubMed

    Braun, M; Sievers, A

    1993-01-01

    The actin cytoskeleton is involved in the positioning of statoliths in tip growing Chara rhizoids. The balance between the acropetally acting gravity force and the basipetally acting net outcome of cytoskeletal force results in the dynamically stable position of the statoliths 10-30 micrometers above the cell tip. A change of the direction and/or the amount of one of these forces in a vertically growing rhizoid results in a dislocation of statoliths. Centrifugation was used as a tool to study the characteristics of the interaction between statoliths and microfilaments (MFs). Acropetal and basipetal accelerations up to 6.5 g were applied with the newly constructed slow-rotating-centrifuge-microscope (NIZEMI). Higher accelerations were applied by means of a conventional centrifuge, namely acropetally 10-200 g and basipetally 10-70 g. During acropetal accelerations (1.4-6g), statoliths were displaced to a new stable position nearer to the cell vertex (12-6.5 micrometers distance to the apical cell wall, respectively), but they did not sediment on the apical cell wall. The original position of the statoliths was reestablished within 30 s after centrifugation. Sedimentation of statoliths and reduction of the growth rates of the rhizoids were observed during acropetal accelerations higher than 50 g. When not only the amount but also the direction of the acceleration were changed in comparison to the natural condition, i.e., during basipetal accelerations (1.0-6.5 g), statoliths were displaced into the subapical zone (up to 90 micrometers distance to the apical cell wall); after 15-20 min the retransport of statoliths to the apex against the direction of acceleration started. Finally, the natural position in the tip was reestablished against the direction of continuous centrifugation. Retransport was observed during accelerations up to 70 g. Under the 1 g condition that followed the retransported statoliths showed an up to 5-fold increase in sedimentation time onto the

  3. An investigation of the close environment of β Cephei with the VEGA/CHARA interferometer

    NASA Astrophysics Data System (ADS)

    Nardetto, N.; Mourard, D.; Tallon-Bosc, I.; Tallon, M.; Berio, P.; Chapellier, E.; Bonneau, D.; Chesneau, O.; Mathias, P.; Perraut, K.; Stee, P.; Blazit, A.; Clausse, J. M.; Delaa, O.; Marcotto, A.; Millour, F.; Roussel, A.; Spang, A.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2011-01-01

    Context. High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star β Cep using the speckle interferometry technique, and features at the limit of resolution (20 milli-arcsec or mas) of the instrument were mentioned that may be due to circumstellar material. β Cep has a magnetic field that might be responsible for a spherical shell or ring-like structure around the star as described by the MHD models. Aims: Using the visible recombiner VEGA installed on the CHARA long-baseline interferometer at Mt. Wilson, we aim to determine the angular diameter of β Cep and resolve its close environment with a spatial resolution up to 1 mas level. Methods: Medium spectral resolution (R = 6000) observations of β Cep were secured with the VEGA instrument over the years 2008 and 2009. These observations were performed with the S1S2 (30 m) and W1W2 (100 m) baselines of the array. Results: We investigated several models to reproduce our observations. A large-scale structure of a few mas is clearly detected around the star with a typical flux relative contribution of 0.23 ± 0.02. Our best model is a co-rotational geometrical thin ring around the star as predicted by magnetically-confined wind shock models. The ring inner diameter is 8.2 ± 0.8 mas and the width is 0.6 ± 0.7 mas. The orientation of the rotation axis on the plane of the sky is PA = 60 ± 1 deg, while the best fit of the mean angular diameter of β Cep gives ΦUD[ V] = 0.22 ± 0.05 mas. Our data are compatible with the predicted position of the close companion of β Cep. Conclusions: These results bring additional constraints on the fundamental parameters and on the future MHD and asteroseismological models of the star.

  4. Molecular Analysis and Localization of CaARA7 a Conventional RAB5 GTPase from Characean Algae.

    PubMed

    Hoepflinger, Marion C; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2015-05-01

    RAB5 GTPases are important regulators of endosomal membrane traffic. Among them Arabidopsis thaliana ARA7/RABF2b is highly conserved and homologues are present in fungal, animal and plant kingdoms. In land plants ARA7 and its homologues are involved in endocytosis and transport towards the vacuole. Here we report on the isolation of an ARA7 homologue (CaARA7/CaRABF2) in the highly evolved characean green alga Chara australis. It encodes a polypeptide of 202 amino acids with a calculated molecular mass of 22.2 kDa and intrinsic GTPase activity. Immunolabelling of internodal cells with a specific antibody reveals CaARA7 epitopes at multivesicular endosomes (MVEs) and at MVE-containing wortmannin (WM) compartments. When transiently expressed in epidermal cells of Nicotiana benthamiana leaves, fluorescently tagged CaARA7 localizes to small organelles (putative MVEs) and WM compartments, and partially colocalizes with AtARA7 and CaARA6, a plant specific RABF1 GTPase. Mutations in membrane anchoring and GTP binding sites alter localization of CaARA7 and affect GTPase activity, respectively. This first detailed study of a conventional RAB5 GTPase in green algae demonstrates that CaARA7 is similar to RAB5 GTPases from land plants and other organisms and shows conserved structure and localization. PMID:25639563

  5. Molecular Analysis and Localization of CaARA7 a Conventional RAB5 GTPase from Characean Algae.

    PubMed

    Hoepflinger, Marion C; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2015-05-01

    RAB5 GTPases are important regulators of endosomal membrane traffic. Among them Arabidopsis thaliana ARA7/RABF2b is highly conserved and homologues are present in fungal, animal and plant kingdoms. In land plants ARA7 and its homologues are involved in endocytosis and transport towards the vacuole. Here we report on the isolation of an ARA7 homologue (CaARA7/CaRABF2) in the highly evolved characean green alga Chara australis. It encodes a polypeptide of 202 amino acids with a calculated molecular mass of 22.2 kDa and intrinsic GTPase activity. Immunolabelling of internodal cells with a specific antibody reveals CaARA7 epitopes at multivesicular endosomes (MVEs) and at MVE-containing wortmannin (WM) compartments. When transiently expressed in epidermal cells of Nicotiana benthamiana leaves, fluorescently tagged CaARA7 localizes to small organelles (putative MVEs) and WM compartments, and partially colocalizes with AtARA7 and CaARA6, a plant specific RABF1 GTPase. Mutations in membrane anchoring and GTP binding sites alter localization of CaARA7 and affect GTPase activity, respectively. This first detailed study of a conventional RAB5 GTPase in green algae demonstrates that CaARA7 is similar to RAB5 GTPases from land plants and other organisms and shows conserved structure and localization.

  6. Molecular Analysis and Localization of CaARA7 a Conventional RAB5 GTPase from Characean Algae

    PubMed Central

    Hoepflinger, Marion C.; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

    2015-01-01

    RAB5 GTPases are important regulators of endosomal membrane traffic. Among them Arabidopsis thaliana ARA7/RABF2b is highly conserved and homologues are present in fungal, animal and plant kingdoms. In land plants ARA7 and its homologues are involved in endocytosis and transport towards the vacuole. Here we report on the isolation of an ARA7 homologue (CaARA7/CaRABF2) in the highly evolved characean green alga Chara australis. It encodes a polypeptide of 202 amino acids with a calculated molecular mass of 22.2 kDa and intrinsic GTPase activity. Immunolabelling of internodal cells with a specific antibody reveals CaARA7 epitopes at multivesicular endosomes (MVEs) and at MVE-containing wortmannin (WM) compartments. When transiently expressed in epidermal cells of Nicotiana benthamiana leaves, fluorescently tagged CaARA7 localizes to small organelles (putative MVEs) and WM compartments, and partially colocalizes with AtARA7 and CaARA6, a plant specific RABF1 GTPase. Mutations in membrane anchoring and GTP binding sites alter localization of CaARA7 and affect GTPase activity, respectively. This first detailed study of a conventional RAB5 GTPase in green algae demonstrates that CaARA7 is similar to RAB5 GTPases from land plants and other organisms and shows conserved structure and localization. PMID:25639563

  7. Neuroprotective Effects of Marine Algae

    PubMed Central

    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. PMID:21673890

  8. Polysaccharides of the red algae.

    PubMed

    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.

  9. XET Activity is Found Near Sites of Growth and Cell Elongation in Bryophytes and Some Green Algae: New Insights into the Evolution of Primary Cell Wall Elongation

    PubMed Central

    Van Sandt, Vicky S. T.; Stieperaere, Herman; Guisez, Yves; Verbelen, Jean-Pierre; Vissenberg, Kris

    2007-01-01

    Background and Aims In angiosperms xyloglucan endotransglucosylase (XET)/hydrolase (XTH) is involved in reorganization of the cell wall during growth and development. The location of oligo-xyloglucan transglucosylation activity and the presence of XTH expressed sequence tags (ESTs) in the earliest diverging extant plants, i.e. in bryophytes and algae, down to the Phaeophyta was examined. The results provide information on the presence of an XET growth mechanism in bryophytes and algae and contribute to the understanding of the evolution of cell wall elongation in general. Methods Representatives of the different plant lineages were pressed onto an XET test paper and assayed. XET or XET-related activity was visualized as the incorporation of fluorescent signal. The Physcomitrella genome database was screened for the presence of XTHs. In addition, using the 3′ RACE technique searches were made for the presence of possible XTH ESTs in the Charophyta. Key Results XET activity was found in the three major divisions of bryophytes at sites corresponding to growing regions. In the Physcomitrella genome two putative XTH-encoding cDNA sequences were identified that contain all domains crucial for XET activity. Furthermore, XET activity was located at the sites of growth in Chara (Charophyta) and Ulva (Chlorophyta) and a putative XTH ancestral enzyme in Chara was identified. No XET activity was identified in the Rhodophyta or Phaeophyta. Conclusions XET activity was shown to be present in all major groups of green plants. These data suggest that an XET-related growth mechanism originated before the evolutionary divergence of the Chlorobionta and open new insights in the evolution of the mechanisms of primary cell wall expansion. PMID:17098750

  10. Raising the intracellular level of inositol 1,4,5-trisphosphate changes plasma membrane ion transport in characean algae.

    PubMed Central

    Thiel, G; MacRobbie, E A; Hanke, D E

    1990-01-01

    Inositol 1,4,5-trisphosphate (InsP3) was introduced into the cytoplasm of characean algae in two different ways: (i) by iontophoretic injection into cytoplasm-enriched fragments from Chara and (ii) by adding InsP3 to the permeabilization medium of locally permeabilized cells of Nitella. In both systems this operation induced a depolarization of the membrane potential, ranging from a few mV to sequences of action potentials. The effect of InsP3 on locally permeabilized Nitella cells was abolished when InsP3 was added together with 30 mM EGTA. When inositol 1,4-bisphosphate or myo-inositol were substituted for InsP3 in this system, there was no change in the membrane potential. On the other hand, increasing the free Ca2+ concentration in the permeabilization medium induced, in a similar fashion to InsP3, action potentials. Similarities between InsP3 and Ca2+ action were also observed upon injection into Chara fragments. Both injections increased an inward current. In the first few seconds after injection the current/voltage characteristics of the InsP3-induced current resembled those of the Ca2(+)-sensitive current. Subsequently, differences between the InsP3- and Ca2(+)-induced phenomena became apparent in that the InsP3-induced current continued to increase while the Ca2(+)-induced current declined, returning to the resting level. Our results suggest that these plant cells contain an InsP3 sensitive system that, under experimental conditions, is able to affect membrane transport via an increase in cytoplasmic free Ca2+. PMID:2112084

  11. Formation of algae growth constitutive relations for improved algae modeling.

    SciTech Connect

    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.

  12. Microscopic Gardens: A Close Look at Algae.

    ERIC Educational Resources Information Center

    Foote, Mary Ann

    1983-01-01

    Describes classroom activities using algae, including demonstration of eutrophication, examination of mating strains, and activities with Euglena. Includes on algal morphology/physiology, types of algae, and field sources for collecting these organisms. (JN)

  13. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    PubMed

    de Bakker, Nancy V J; van Bodegom, P M; van de Poll, W H; Boelen, P; Nat, E; Rozema, J; Aerts, R

    2005-06-01

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied by combining a glasshouse experiment in which plants were exposed to various levels of UV-B radiation and field measurements in two freshwater systems dominated by charophytes in the Netherlands. The glasshouse experiment showed that charophytes were sensitive to UV-B radiation. UV-B radiation negatively affected growth, while it increased levels of DNA damage in Chara aspera. Moreover, the charophytes did not seem to develop UV-B screens to protect against UV-B radiation since no increase in UV-B absorbing compounds was found. At field conditions, both spectroradiometrical measurements and DNA dosimeters showed that UV-B radiation was attenuated quickly in both freshwater systems, indicating that UV-B does not reach the submerged charophyte vegetation. However, specific conditions, like fluctuating water tables, may result in UV-B exposure to charophytes for certain periods annually.

  14. Calcareous algae bioclast contribution to sediment enrichment by arsenic on the Brazilian subtropical coast

    NASA Astrophysics Data System (ADS)

    Mirlean, Nicolai; Baisch, Paulo; Travassos, Marcelo P.; Nassar, Cristina

    2011-02-01

    Arsenic levels (up to 130 mg kg-1) substantially exceeding the official threshold have recently been documented in beach and nearshore sediments along more than 50 km of coastline in the Brazilian state of Espírito Santo between 19°50' and 20°12'S. In an attempt to assess the sources of this enrichment, we performed a study on arsenic distribution in the main mineral substances and living organisms in the beach environment. Laboratory tests on arsenic retention by beach carbonate debris have also been carried out. The data suggest that sedimentary arsenic occurs largely bound to particles of the calcareous red alga Corallina panizzoi, whereby live specimens contained much smaller amounts of this metalloid than was the case for nonliving material (2.4 and 20.3 mg kg-1, respectively). Experimental tests confirmed the ability of C. panizzoi detritus to retain arsenic at pH intervals and ionic strength characteristic of seawater. There are two potential sources of that metalloid for calcareous debris in sediments: brown macroalgae, which were found to contain high levels of As (up to 66.3 mg kg-1), and ferruginized sandstones (up to 23.0 mg kg-1). We argue that any contribution of brown algae to beach sediment enrichment by As would be minor, and consider the ferrous sandstones from coastal sedimentary rocks of the Barreiras Group as the principal large-scale source of arsenic in the marine environment of Espírito Santo. The experimental data, together with field studies, corroborate the interpretation that arsenic anomalies in sediments with calcareous debris can form when weathered continental rocks even only slightly enriched in As are leached by marine waters, and the As is at least partially retained by biogenic calcareous detritus in nearshore sediments. Considering that rocks of the Barreiras Group are exposed to marine erosion far to the north of Espírito Santo, we estimate that marine sediments containing calcareous material are "anomalously" enriched in

  15. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false 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...

  16. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false 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...

  17. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false 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...

  18. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2010 CFR

    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...

  19. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  20. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  1. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  2. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1121 Red algae. (a) Red algae are seaweeds of the species...

  3. 21 CFR 184.1121 - Red algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Red algae. 184.1121 Section 184.1121 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1121 Red algae. (a) Red algae are seaweeds of the species Gloiopeltis furcata, Porphyra...

  4. 21 CFR 184.1120 - Brown algae.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Brown algae. 184.1120 Section 184.1120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1120 Brown algae. (a) Brown algae are seaweeds of the species Analipus japonicus, Eisenia...

  5. Biological importance of marine algae

    PubMed Central

    El Gamal, Ali A.

    2009-01-01

    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. PMID:23960716

  6. Magnetite and Magnetotaxis in Algae

    PubMed Central

    de Araujo, F. F. Torres; Pires, M. A.; Frankel, R. B.; Bicudo, C. E. M.

    1986-01-01

    Magnetotactic algae of the genus Anisonema (Euglenophyceae) have been isolated from a coastal mangrove swamp in northeastern Brazil. The magnetotactic response is based on a permanent magnetic dipole moment per cell ∼7 10-10 emu. Each cell contains many magnetite (Fe3O4) particles organized in chains. ImagesFIGURE 2FIGURE 1FIGURE 3 PMID:19431684

  7. Algae. LC Science Tracer Bullet.

    ERIC Educational Resources Information Center

    Niskern, Diana, Comp.

    The plants and plantlike organisms informally grouped together as algae show great diversity of form and size and occur in a wide variety of habitats. These extremely important photosynthesizers are also economically significant. For example, some species contaminate water supplies; others provide food for aquatic animals and for man; still others…

  8. Interferometric radii of bright Kepler stars with the CHARA Array: θ Cygni and 16 Cygni A and B

    NASA Astrophysics Data System (ADS)

    White, T. R.; Huber, D.; Maestro, V.; Bedding, T. R.; Ireland, M. J.; Baron, F.; Boyajian, T. S.; Che, X.; Monnier, J. D.; Pope, B. J. S.; Roettenbacher, R. M.; Stello, D.; Tuthill, P. G.; Farrington, C. D.; Goldfinger, P. J.; McAlister, H. A.; Schaefer, G. H.; Sturmann, J.; Sturmann, L.; ten Brummelaar, T. A.; Turner, N. H.

    2013-08-01

    We present the results of long-baseline optical interferometry observations using the Precision Astronomical Visual Observations (PAVO) beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array to measure the angular sizes of three bright Kepler stars: θ Cygni, and both components of the binary system 16 Cygni. Supporting infrared observations were made with the Michigan Infrared Combiner (MIRC) and Classic beam combiner, also at the CHARA Array. We find limb-darkened angular diameters of 0.753 ± 0.009 mas for θ Cyg, 0.539 ± 0.007 mas for 16 Cyg A and 0.490 ± 0.006 mas for 16 Cyg B. The Kepler Mission has observed these stars with outstanding photometric precision, revealing the presence of solar-like oscillations. Due to the brightness of these stars the oscillations have exceptional signal-to-noise, allowing for detailed study through asteroseismology, and are well constrained by other observations. We have combined our interferometric diameters with Hipparcos parallaxes, spectrophotometric bolometric fluxes and the asteroseismic large frequency separation to measure linear radii (θ Cyg: 1.48 ± 0.02 R⊙, 16 Cyg A: 1.22 ± 0.02 R⊙, 16 Cyg B: 1.12 ± 0.02 R⊙), effective temperatures (θ Cyg: 6749 ± 44 K, 16 Cyg A: 5839 ± 42 K, 16 Cyg B: 5809 ± 39 K) and masses (θ Cyg: 1.37 ± 0.04 M⊙, 16 Cyg A: 1.07 ± 0.05 M⊙, 16 Cyg B: 1.05 ± 0.04 M⊙) for each star with very little model dependence. The measurements presented here will provide strong constraints for future stellar modelling efforts.

  9. Separated Fringe Packet Observations with the CHARA Array. I. Methods and New Orbits for χ Draconis, HD 184467, and HD 198084

    NASA Astrophysics Data System (ADS)

    Farrington, C. D.; ten Brummelaar, T. A.; Mason, B. D.; Hartkopf, W. I.; McAlister, H. A.; Raghavan, D.; Turner, N. H.; Sturmann, L.; Sturmann, J.; Ridgway, S. T.

    2010-06-01

    We present the modification of the orbits of χ Draconis and HD 184467, and a completely new orbit for HD 198084, including data taken at the Center for High Angular Resolution Astronomy (CHARA) Array. These data were obtained using a modification of the technique of separated fringe packets (SFPs). The accuracy of the SFP data surpasses that of data taken by speckle, but the technique is much more time and labor intensive. Additionally, using SFPs with the CHARA Array, it is possible to obtain separations below the detection range of speckle interferometry (>=30 mas) above the range in "classic" long-baseline interferometry where fringes from a binary overlap are no longer separated (<=10 mas). Using spectroscopic binary systems with published speckle orbits, we are able to test our new measurements against their ephemerides to calibrate the method as well as produce entirely new orbits for systems with no current astrometric observations.

  10. The remote sensing of algae

    NASA Technical Reports Server (NTRS)

    Thorne, J. F.

    1977-01-01

    State agencies need rapid, synoptic and inexpensive methods for lake assessment to comply with the 1972 Amendments to the Federal Water Pollution Control Act. Low altitude aerial photography may be useful in providing information on algal type and quantity. Photography must be calibrated properly to remove sources of error including airlight, surface reflectance and scene-to-scene illumination differences. A 550-nm narrow wavelength band black and white photographic exposure provided a better correlation to algal biomass than either red or infrared photographic exposure. Of all the biomass parameters tested, depth-integrated chlorophyll a concentration correlated best to remote sensing data. Laboratory-measured reflectance of selected algae indicate that different taxonomic classes of algae may be discriminated on the basis of their reflectance spectra.

  11. Algae control for hydrogeneration canals

    SciTech Connect

    Grahovac, P.

    1997-02-16

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to assess and develop control practices for nuisance algae growth in power canal that delivers water to hydro-generation facilities. This growth results in expenditures related not only to lost generation but also labor and materials costs associated with implementing remediation procedures. On an industry-wide basis these costs associated with nuisance algal growth are estimated to be several million dollars per year.

  12. Parasites in algae mass culture

    PubMed Central

    Carney, Laura T.; Lane, Todd W.

    2014-01-01

    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. PMID:24936200

  13. Halogenated Compounds from Marine Algae

    PubMed Central

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-01-01

    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. PMID:20948909

  14. Detection of gravity-induced polarity of cytoplasmic streaming in Chara

    NASA Technical Reports Server (NTRS)

    Staves, M. P.; Wayne, R.; Leopold, A. C.

    1995-01-01

    Gravity induces a polarity of cytoplasmic streaming in vertically-oriented internodal cells of characean algae. The motive force that powers cytoplasmic streaming is generated at the ectoplasmic/endoplasmic interface. The velocity of streaming, which is about 100 micrometers/s at this interface, decreases with distance from the interface on either side of the cell to 0 micrometers/s near the middle. Therefore, when discussing streaming velocity it is necessary to specify the tangential plane through the cell in which streaming is being measured. This is easily done with a moderate resolution light microscope (which has a lateral resolution of 0.6 micrometers and a depth of field of 1.4 micrometers), but is obscured when using any low resolution technique, such as low magnification light microscopy or laser Doppler spectroscopy. In addition, the effect of gravity on the polarity of cytoplasmic streaming declines with increasing physiological age of isolated cells. Using a classical mechanical analysis, we show that the effect of gravity on the polarity of cytoplasmic streaming cannot result from the effect of gravity acting directly on individual cytoplasmic particles. We suggest that gravity may best be perceived by the entire cell at the plasma membrane-extracellular matrix junction.

  15. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-15

    We consider the development of harmful algae blooms (HABs) in a lake with uncertain nutrients inflow. Two general frameworks, Fokker-Planck equation and the PDF methods, are developed to quantify the resultant concentration uncertainty of various algae groups, via deriving a deterministic equation of their joint probability density function (PDF). A computational example is examined to study the evolution of cyanobacteria (the blue-green algae) and the impacts of initial concentration and inflow-outflow ratio.

  16. The CHARA Array resolves the long-period Wolf-Rayet binaries WR 137 and WR 138

    NASA Astrophysics Data System (ADS)

    Richardson, Noel D.; Shenar, Tomer; Roy-Loubier, Olivier; Schaefer, Gail; Moffat, Anthony F. J.; St-Louis, Nicole; Gies, Douglas R.; Farrington, Chris; Hill, Grant M.; Williams, Peredur M.; Gordon, Kathryn; Pablo, Herbert; Ramiaramanantsoa, Tahina

    2016-10-01

    We report on interferometric observations with the CHARA Array of two classical Wolf-Rayet (WR) stars in suspected binary systems, namely WR 137 and WR 138. In both cases, we resolve the component stars to be separated by a few milliarcseconds. The data were collected in the H band, and provide a measure of the fractional flux for both stars in each system. We find that the WR star is the dominant H-band light source in both systems (fWR,137 = 0.59 ± 0.04; fWR,138 = 0.67 ± 0.01), which is confirmed through both comparisons with estimated fundamental parameters for WR stars and O dwarfs, as well as through spectral modelling of each system. Our spectral modelling also provides fundamental parameters for the stars and winds in these systems. The results on WR 138 provide evidence that it is a binary system which may have gone through a previous mass-transfer episode to create the WR star. The separation and position of the stars in the WR 137 system together with previous results from the IOTA interferometer provides evidence that the binary is seen nearly edge-on. The possible edge-on orbit of WR 137 aligns well with the dust production site imaged by the Hubble Space Telescope during a previous periastron passage, showing that the dust production may be concentrated in the orbital plane.

  17. Fundamental Properties of Stars Using Asteroseismology from Kepler and CoRoT and Interferometry from the CHARA Array

    NASA Astrophysics Data System (ADS)

    Huber, D.; Ireland, M. J.; Bedding, T. R.; Brandão, I. M.; Piau, L.; Maestro, V.; White, T. R.; Bruntt, H.; Casagrande, L.; Molenda-Żakowicz, J.; Silva Aguirre, V.; Sousa, S. G.; Barclay, T.; Burke, C. J.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Cunha, M. S.; De Ridder, J.; Farrington, C. D.; Frasca, A.; García, R. A.; Gilliland, R. L.; Goldfinger, P. J.; Hekker, S.; Kawaler, S. D.; Kjeldsen, H.; McAlister, H. A.; Metcalfe, T. S.; Miglio, A.; Monteiro, M. J. P. F. G.; Pinsonneault, M. H.; Schaefer, G. H.; Stello, D.; Stumpe, M. C.; Sturmann, J.; Sturmann, L.; ten Brummelaar, T. A.; Thompson, M. J.; Turner, N.; Uytterhoeven, K.

    2012-11-01

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes, and high-resolution spectroscopy, we derive a full set of near-model-independent fundamental properties for the sample. We first use these properties to test asteroseismic scaling relations for the frequency of maximum power (νmax) and the large frequency separation (Δν). We find excellent agreement within the observational uncertainties, and empirically show that simple estimates of asteroseismic radii for main-sequence stars are accurate to <~ 4%. We furthermore find good agreement of our measured effective temperatures with spectroscopic and photometric estimates with mean deviations for stars between T eff = 4600-6200 K of -22 ± 32 K (with a scatter of 97 K) and -58 ± 31 K (with a scatter of 93 K), respectively. Finally, we present a first comparison with evolutionary models, and find differences between observed and theoretical properties for the metal-rich main-sequence star HD 173701. We conclude that the constraints presented in this study will have strong potential for testing stellar model physics, in particular when combined with detailed modeling of individual oscillation frequencies.

  18. CHARA/MIRC observations of two M supergiants in Perseus OB1: Temperature, bayesian modeling, and compressed sensing imaging

    SciTech Connect

    Baron, F.; Monnier, J. D.; Anderson, M.; Aarnio, A.; Kiss, L. L.; Neilson, H. R.; Zhao, M.; Pedretti, E.; Thureau, N.; Ten Brummelaar, T. A.; Sturmann, J.; Sturmann, L.; Turner, N.; Ridgway, S. T.; McAlister, H. A.

    2014-04-10

    Two red supergiants (RSGs) of the Per OB1 association, RS Per and T Per, have been observed in the H band using the Michigan Infra-Red Combiner (MIRC) instrument at the CHARA array. The data show clear evidence of a departure from circular symmetry. We present here new techniques specially developed to analyze such cases, based on state-of-the-art statistical frameworks. The stellar surfaces are first modeled as limb-darkened disks based on SATLAS models that fit both MIRC interferometric data and publicly available spectrophotometric data. Bayesian model selection is then used to determine the most probable number of spots. The effective surface temperatures are also determined and give further support to the recently derived hotter temperature scales of RSGs. The stellar surfaces are reconstructed by our model-independent imaging code SQUEEZE, making use of its novel regularizer based on Compressed Sensing theory. We find excellent agreement between the model-selection results and the reconstructions. Our results provide evidence for the presence of near-infrared spots representing about 3%-5% of the stellar flux.

  19. FUNDAMENTAL PROPERTIES OF STARS USING ASTEROSEISMOLOGY FROM KEPLER AND CoRoT AND INTERFEROMETRY FROM THE CHARA ARRAY

    SciTech Connect

    Huber, D.; Ireland, M. J.; Bedding, T. R.; Maestro, V.; White, T. R.; Brandao, I. M.; Sousa, S. G.; Cunha, M. S.; Piau, L.; Bruntt, H.; Aguirre, V. Silva; Christensen-Dalsgaard, J.; Casagrande, L.; Molenda-Zakowicz, J.; Barclay, T.; De Ridder, J.; Farrington, C. D.; Frasca, A.; and others

    2012-11-20

    We present results of a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT. By combining interferometric angular diameters, Hipparcos parallaxes, asteroseismic densities, bolometric fluxes, and high-resolution spectroscopy, we derive a full set of near-model-independent fundamental properties for the sample. We first use these properties to test asteroseismic scaling relations for the frequency of maximum power ({nu}{sub max}) and the large frequency separation ({Delta}{nu}). We find excellent agreement within the observational uncertainties, and empirically show that simple estimates of asteroseismic radii for main-sequence stars are accurate to {approx}< 4%. We furthermore find good agreement of our measured effective temperatures with spectroscopic and photometric estimates with mean deviations for stars between T {sub eff} = 4600-6200 K of -22 {+-} 32 K (with a scatter of 97 K) and -58 {+-} 31 K (with a scatter of 93 K), respectively. Finally, we present a first comparison with evolutionary models, and find differences between observed and theoretical properties for the metal-rich main-sequence star HD 173701. We conclude that the constraints presented in this study will have strong potential for testing stellar model physics, in particular when combined with detailed modeling of individual oscillation frequencies.

  20. Petroleum coke and soft tailings sediment in constructed wetlands may contribute to the uptake of trace metals by algae and aquatic invertebrates.

    PubMed

    Baker, Leanne F; Ciborowski, Jan J H; MacKinnon, Michael D

    2012-01-01

    The fate of trace metals in pore water collected from wetland sediments and organisms exposed to petroleum coke were evaluated within in situ aquatic microcosms. Oil sands operators of Fort McMurray, Alberta, Canada produced 60 million tonnes of petroleum coke by 2008, containing elevated concentrations of sulphur and several trace metals commonly seen in oil sands materials. This material may be included in the construction of reclaimed wetlands. Microcosms were filled with a surface layer of petroleum coke over mine-waste sediments and embedded in a constructed wetland for three years to determine how these materials would affect the metal concentrations in the sediment pore water, colonizing wetland plants and benthic invertebrates. Petroleum coke treatments produced significantly elevated levels of Ni. We also found unexpectedly higher concentrations of metals in "consolidated tailings" waste materials, potentially due to the use of oil sands-produced gypsum, and higher background concentration of elements in the sediment used in the controls. A trend of higher concentrations of V, Ni, La, and Y was present in the tissues of the colonizing macrophytic alga Chara spp. Aeshnid dragonflies may also be accumulating V. These results indicate that the trace metals present in some oil sands waste materials could be taken up by aquatic macro-algae and some wetland invertebrates if these materials are included in reclaimed wetlands.

  1. Characterization of MADS-box genes in charophycean green algae and its implication for the evolution of MADS-box genes.

    PubMed

    Tanabe, Yoichi; Hasebe, Mitsuyasu; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Kitani, Masakazu; Henschel, Katrin; Münster, Thomas; Theissen, Günter; Nozaki, Hisayoshi; Ito, Motomi

    2005-02-15

    The MADS-box genes of land plants are extensively diverged to form a superfamily and are important in various aspects of development including the specification of floral organs as homeotic selector genes. The closest relatives of land plants are the freshwater green algae charophyceans. To study the origin and evolution of land plant MADS-box genes, we characterized these genes in three charophycean green algae: the stonewort Chara globularis, the coleochaete Coleochaete scutata, and the desmid Closterium peracerosum-strigosum-littorale complex. Phylogenetic analyses suggested that MADS-box genes diverged extensively in the land plant lineage after the separation of charophyceans from land plants. The stonewort C. globularis mRNA was specifically detected in the oogonium and antheridium together with the egg and spermatozoid during their differentiation. The expression of the C. peracerosum-strigosum-littorale-complex gene increased when vegetative cells began to differentiate into gametangial cells and decreased after fertilization. These expression patterns suggest that the precursors of land plant MADS-box genes originally functioned in haploid reproductive cell differentiation and that the haploid MADS-box genes were recruited into a diploid generation during the evolution of land plants.

  2. Cultivation of macroscopic marine algae

    SciTech Connect

    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.

  3. Hydrogen metabolism of photosynthetic bacteria and algae

    SciTech Connect

    Kumazawa, S.; Mitsui, A.

    1982-01-01

    The metabolism, metabolic pathways and biochemistry of hydrogen in photosynthetic bacteria and algae are reviewed. Detailed information on the occurrence and measurement of hydrogenase activity is presented. Hydrogen production rates for different species of algae and bacteria are presented. 173 references, 1 figure, 7 tables.

  4. SSMILes: Measuring the Nutrient Tolerance of Algae.

    ERIC Educational Resources Information Center

    Hedgepeth, David J.

    1995-01-01

    Presents an activity integrating mathematics and science intended to introduce students to the use of metric measurement of mass as a way to increase the meaningfulness of observations about variables in life sciences. Involves measuring the nutrient tolerance of algae. Contains a reproducible algae nutrient graph. (Author/MKR)

  5. Take a Dip! Culturing Algae Is Easy.

    ERIC Educational Resources Information Center

    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.…

  6. Nutritional And Taste Characteristics Of Algae

    NASA Technical Reports Server (NTRS)

    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.

  7. Effect of Dead Algae on Soil Permeability

    SciTech Connect

    Harvey, R.S.

    2003-02-21

    Since existing basins support heavy growths of unicellular green algae which may be killed by temperature variation or by inadvertent pH changes in waste and then deposited on the basin floor, information on the effects of dead algae on soil permeability was needed. This study was designed to show the effects of successive algal kills on the permeability of laboratory soil columns.

  8. Antarctic sea ice thickness affects algae populations

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-01-01

    In the waters off Antarctica, algae grow and live in the sea ice that surrounds the southern continent—a floating habitat sure to change as the planet warms. As with most aquatic ecosystems, microscopic algae form the base of the Southern Ocean food web. Distinct algae populations reside in the sea ice surface layers, on the ice's underside, and within the floating ice itself. The algae that reside on the floating ice's underside are particularly important for the region's krill population, while those on the interior or surface layers are less accessible. Understanding how changing sea ice properties will affect the regional biology, then, depends on understanding how algae populations interact with the ice.

  9. The ice nucleation activity of extremophilic algae.

    PubMed

    Kviderova, Jana; Hajek, Josef; Worland, Roger M

    2013-01-01

    Differences in the level of cold acclimation and cryoprotection estimated as ice nucleation activity in snow algae (Chlamydomonas cf. nivalis and Chloromonas nivalis), lichen symbiotic algae (Trebouxia asymmetrica, Trebouxia erici and Trebouxia glomerata), and a mesophilic strain (Chlamydomonas reinhardti) were evaluated. Ice nucleation activity was measured using the freezing droplet method. Measurements were performed using suspensions of cells of A750 (absorbance at 750 nm) ~ 1, 0.1, 0.01 and 0.001 dilutions for each strain. The algae had lower ice nucleation activity, with the exception of Chloromonas nivalis contaminated by bacteria. The supercooling points of the snow algae were higher than those of lichen photobionts. The supercooling points of both, mesophilic and snow Chlamydomonas strains were similar. The lower freezing temperatures of the lichen algae may reflect either the more extreme and more variable environmental conditions of the original localities or the different cellular structure of the strains examined.

  10. Composting of waste algae: a review.

    PubMed

    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.

  11. Flocculation of model algae under shear.

    SciTech Connect

    Pierce, Flint; Lechman, Jeremy B.

    2010-11-01

    We present results of molecular dynamics simulations of the flocculation of model algae particles under shear. We study the evolution of the cluster size distribution as well as the steady-state distribution as a function of shear rates and algae interaction parameters. Algal interactions are modeled through a DLVO-type potential, a combination of a HS colloid potential (Everaers) and a yukawa/colloid electrostatic potential. The effect of hydrodynamic interactions on aggregation is explored. Cluster strucuture is determined from the algae-algae radial distribution function as well as the structure factor. DLVO parameters including size, salt concentration, surface potential, initial volume fraction, etc. are varied to model different species of algae under a variety of environmental conditions.

  12. Algae inhibition experiment and load characteristics of the algae solution

    NASA Astrophysics Data System (ADS)

    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.

  13. DNA sequence determinants of nuclear protein binding to the c-Ha-ras antioxidant/electrophile response element in vascular smooth muscle cells: identification of Nrf2 and heat shock protein 90 beta as heterocomplex components.

    PubMed

    Miller, Kimberly P; Ramos, Kenneth S

    2005-01-01

    The antioxidant/electrophile response element (ARE/EpRE) is a cis-acting element involved in redox regulation of c-Ha-ras gene. Protein binding to the ARE/EpRE may be credited to deoxyribonucleic acid sequence; therefore, studies were conducted to evaluate the influence of internal and flanking regions to the 10-bp human c-Ha-ras ARE/EpRE core (hHaras10) on nuclear protein binding in oxidant-treated vascular smooth muscle cells. A protein doublet bound to an extended oligonucleotide comprising the ARE/EpRE core in genomic context (hHaras27), whereas a single complex bound to hHarasl0. Protein binding involved specific interactions of 25- and 23-kDa proteins with hHarasl0, and binding of 80-, 65-, and 55-kDa proteins to hHaras27. Competition assays with hNQO1 and rGSTA2 confirmed the specificity of deoxyribonucleic acid-protein interactions and indicated preferred binding of p25 and p23 to the c-Ha-ras ARE/EpRE. "NNN" sequences within the core afforded unique protein-binding profiles to the c-Ha-ras ARE/EpRE. In addition, Nrf2 and heat shock protein 90beta (p80) were identified as components of the c-Ha-ras ARE/EpRE heterocomplex. We conclude that both internal bases and flanking sequences regulate nuclear protein recruitment and complex assembly on the c-Ha-ras ARE/EpRE.

  14. Molecular and biochemical analysis of the first ARA6 homologue, a RAB5 GTPase, from green algae.

    PubMed

    Hoepflinger, Marion C; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Nishiyama, Tomoaki; Sakayama, Hidetoshi; Hammerl, Peter; Tenhaken, Raimund; Ueda, Takashi; Foissner, Ilse

    2013-12-01

    RAB5 GTPases are important regulators of endosomal membrane traffic in yeast, plants, and animals. A specific subgroup of this family, the ARA6 group, has been described in land plants including bryophytes, lycophytes, and flowering plants. Here, we report on the isolation of an ARA6 homologue in a green alga. CaARA6 (CaRABF1) from Chara australis, a member of the Characeae that is a close relative of land plants, encodes a polypeptide of 237 aa with a calculated molecular mass of 25.4 kDa, which is highly similar to ARA6 members from Arabidopsis thaliana and other land plants and has GTPase activity. When expressed in Nicotiana benthamiana leaf epidermal cells, fluorescently tagged CaARA6 labelled organelles with diameters between 0.2 and 1.2 µm, which co-localized with fluorescently tagged AtARA6 known to be present on multivesicular endosomes. Mutations in the membrane-anchoring and GTP-binding sites altered the localization of CaARA6 comparable to that of A. thaliana ARA6 (RABF1). In characean internodal cells, confocal immunofluorescence and immunogold electron microscopy with antibodies against AtARA6 and CaARA6 revealed ARA6 epitopes not only at multivesicular endosomes but also at the plasma membrane, including convoluted domains (charasomes), and at the trans-Golgi network. Our findings demonstrate that ARA6-like proteins have a more ancient origin than previously thought. They indicate further that ARA6-like proteins could have different functions in spite of the high similarity between characean algae and flowering plants.

  15. Molecular and biochemical analysis of the first ARA6 homologue, a RAB5 GTPase, from green algae.

    PubMed

    Hoepflinger, Marion C; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Nishiyama, Tomoaki; Sakayama, Hidetoshi; Hammerl, Peter; Tenhaken, Raimund; Ueda, Takashi; Foissner, Ilse

    2013-12-01

    RAB5 GTPases are important regulators of endosomal membrane traffic in yeast, plants, and animals. A specific subgroup of this family, the ARA6 group, has been described in land plants including bryophytes, lycophytes, and flowering plants. Here, we report on the isolation of an ARA6 homologue in a green alga. CaARA6 (CaRABF1) from Chara australis, a member of the Characeae that is a close relative of land plants, encodes a polypeptide of 237 aa with a calculated molecular mass of 25.4 kDa, which is highly similar to ARA6 members from Arabidopsis thaliana and other land plants and has GTPase activity. When expressed in Nicotiana benthamiana leaf epidermal cells, fluorescently tagged CaARA6 labelled organelles with diameters between 0.2 and 1.2 µm, which co-localized with fluorescently tagged AtARA6 known to be present on multivesicular endosomes. Mutations in the membrane-anchoring and GTP-binding sites altered the localization of CaARA6 comparable to that of A. thaliana ARA6 (RABF1). In characean internodal cells, confocal immunofluorescence and immunogold electron microscopy with antibodies against AtARA6 and CaARA6 revealed ARA6 epitopes not only at multivesicular endosomes but also at the plasma membrane, including convoluted domains (charasomes), and at the trans-Golgi network. Our findings demonstrate that ARA6-like proteins have a more ancient origin than previously thought. They indicate further that ARA6-like proteins could have different functions in spite of the high similarity between characean algae and flowering plants. PMID:24127512

  16. Algae biodiesel - a feasibility report

    PubMed Central

    2012-01-01

    Background Algae biofuels have been studied numerous times including the Aquatic Species program in 1978 in the U.S., smaller laboratory research projects and private programs. Results Using Molina Grima 2003 and Department of Energy figures, captial costs and operating costs of the closed systems and open systems were estimated. Cost per gallon of conservative estimates yielded $1,292.05 and $114.94 for closed and open ponds respectively. Contingency scenarios were generated in which cost per gallon of closed system biofuels would reach $17.54 under the generous conditions of 60% yield, 50% reduction in the capital costs and 50% hexane recovery. Price per gallon of open system produced fuel could reach $1.94 under generous assumptions of 30% yield and $0.2/kg CO2. Conclusions Current subsidies could allow biodiesel to be produced economically under the generous conditions specified by the model. PMID:22540986

  17. DGDG and Glycolipids in Plants and Algae.

    PubMed

    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). PMID:27023231

  18. Algae Biofuel in the Nigerian Energy Context

    NASA Astrophysics Data System (ADS)

    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.

  19. DGDG and Glycolipids in Plants and Algae.

    PubMed

    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).

  20. Cytoplasmic streaming velocity as a plant size determinant.

    PubMed

    Tominaga, Motoki; Kimura, Atsushi; Yokota, Etsuo; Haraguchi, Takeshi; Shimmen, Teruo; Yamamoto, Keiichi; Nakano, Akihiko; Ito, Kohji

    2013-11-11

    Cytoplasmic streaming is active transport widely occurring in plant cells ranging from algae to angiosperms. Although it has been revealed that cytoplasmic streaming is generated by organelle-associated myosin XI moving along actin bundles, the fundamental function in plants remains unclear. We generated high- and low-speed chimeric myosin XI by replacing the motor domains of Arabidopsis thaliana myosin XI-2 with those of Chara corallina myosin XI and Homo sapiens myosin Vb, respectively. Surprisingly, the plant sizes of the transgenic Arabidopsis expressing high- and low-speed chimeric myosin XI-2 were larger and smaller, respectively, than that of the wild-type plant. This size change correlated with acceleration and deceleration, respectively, of cytoplasmic streaming. Our results strongly suggest that cytoplasmic streaming is a key determinant of plant size. Furthermore, because cytoplasmic streaming is a common system for intracellular transport in plants, our system could have applications in artificial size control in plants.

  1. c-Ha-ras down regulates the alpha-fetoprotein gene but not the albumin gene in human hepatoma cells.

    PubMed Central

    Nakao, K; Lawless, D; Ohe, Y; Miyao, Y; Nakabayashi, H; Kamiya, H; Miura, K; Ohtsuka, E; Tamaoki, T

    1990-01-01

    We studied the effects of transfection of the normal c-Ha-ras gene, rasGly-12, and its oncogenic mutant, rasVal-12, on expression of the alpha-fetoprotein (AFP) and albumin genes in a human hepatoma cell line, HuH-7. The mutant and, to a lesser extent, the normal ras gene caused reduction of the AFP mRNA but not the albumin mRNA level in transfected HuH-7 cells. Cotransfection experiments with a rasVal-12 expression plasmid and a chloramphenicol acetyltransferase reporter gene fused to AFP regulatory sequences showed that rasVal-12 suppressed the activity of enhancer and promoter regions containing A + T-rich sequences (AT motif). In contrast, rasVal-12 did not affect the promoter activity of the albumin and human hepatitis B virus pre-S1 genes even though these promoters contain homologous A + T-rich elements. ras transfection appeared to induce phosphorylation of nuclear proteins that interact with the AFP AT motif, since gel mobility analysis revealed the formation of slow-moving complexes which was reversed by phosphatase treatment. However, similar changes in complex formation were observed with the albumin and hepatitis B surface antigen pre-S1 promoters. Therefore, this effect alone cannot explain the specific down regulation of the AFP promoter and enhancer activity. ras-mediated suppression of the AFP gene may reflect the process of developmental gene regulation in which AFP gene transcription is controlled by a G-protein-linked signal transduction cascade triggered by external growth stimuli. Images PMID:1690841

  2. Errors When Extracting Oil from Algae

    NASA Astrophysics Data System (ADS)

    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

  3. Method and apparatus for processing algae

    SciTech Connect

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite; Di Salvo, Roberto

    2012-07-03

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells. The lysate separates into at least two layers including a lipid-containing hydrophobic layer and an ionic liquid-containing hydrophilic layer. A salt or salt solution may be used to remove water from the ionic liquid-containing layer before the ionic liquid is reused. The used salt may also be dried and/or concentrated and reused. The method can operate at relatively low lysis, processing, and recycling temperatures, which minimizes the environmental impact of algae processing while providing reusable biofuels and other useful products.

  4. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  5. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  6. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  7. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  8. 21 CFR 73.275 - Dried algae meal.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Dried algae meal. 73.275 Section 73.275 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.275 Dried algae meal. (a) Identity. The color additive dried algae meal is a dried mixture of algae cells (genus Spongiococcum, separated from its culture...

  9. Pyogenic Flexor Tenosynovitis Caused by Shewanella algae.

    PubMed

    Fluke, Erin C; Carayannopoulos, Nikoletta L; Lindsey, Ronald W

    2016-07-01

    Pyogenic flexor tenosynovitis is an orthopedic emergency most commonly caused by Staphylococcus aureus and streptococci and occasionally, when associated with water exposure, Mycobacterium marinum. Shewanella algae, a gram-negative bacillus found in warm saltwater environments, has infrequently been reported to cause serious soft tissue infections and necrosis. In this case, S. algae caused complicated flexor tenosynovitis requiring open surgical irrigation and debridement. Flexor tenosynovitis caused by S. algae rapidly presented with all 4 Kanavel cardinal signs as well as subcutaneous purulence, ischemia, and necrosis, thus meeting the requirements for Pang et al group III classification of worst prognosis. Because of its rarity and virulence, S. algae should always be considered in cases of flexor tenosynovitis associated with traumatic water exposure to treat and minimize morbidity appropriately.

  10. 2011 Biomass Program Platform Peer Review: Algae

    SciTech Connect

    Yang, Joyce

    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.

  11. Collection, Isolation and Culture of Marine Algae.

    ERIC Educational Resources Information Center

    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)

  12. Stochastic Forecasting of Algae Blooms in Lakes

    SciTech Connect

    Wang, Peng; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.

    2013-01-03

    We consider a general framework to predict the development of harmful algal blooms (HABs) in a lake driven by uncertain parameters. To quantify the concentration uncertainty of those algae groups via their joint probabilistic density function (PDF), we explore an approach based on the Fokker-Planck equation. Our result is presented in an example where abundant nutrients contribute to the proliferation of cyanobacteria and other minor algae groups.

  13. Mechano-perception in Chara cells: the influence of salinity and calcium on touch-activated receptor potentials, action potentials and ion transport.

    PubMed

    Shepherd, Virginia A; Beilby, Mary J; Al Khazaaly, Sabah A S; Shimmen, Teruo

    2008-11-01

    This paper investigates the impact of increased salinity on touch-induced receptor and action potentials of Chara internodal cells. We resolved underlying changes in ion transport by current/voltage analysis. In a saline medium with a low Ca(2+) ion concentration [(Ca(2+))(ext)], the cell background conductance significantly increased and proton pump currents declined to negligible levels, depolarizing the membrane potential difference (PD) to the excitation threshold [action potential (AP)(threshold)]. The onset of spontaneous repetitive action potentials further depolarized the PD, activating K(+) outward rectifying (KOR) channels. K(+) efflux was then sustained and irrevocable, and cells were desensitized to touch. However, when [Ca(2+)](ext) was high, the background conductance increased to a lesser extent and proton pump currents were stimulated, establishing a PD narrowly negative to AP(threshold). Cells did not spontaneously fire, but became hypersensitive to touch. Even slight touch stimulus induced an action potential and further repetitive firing. The duration of each excitation was extended when [Ca(2+)](ext) was low. Cell viability was prolonged in the absence of touch stimulus. Chara cells eventually depolarize and die in the saline media, but touch-stimulated and spontaneous excitation accelerates the process in a Ca(2+)-dependent manner. Our results have broad implications for understanding the interactions between mechano-perception and salinity stress in plants.

  14. The compact Hα emitting regions of the Herbig Ae/Be stars HD 179218 and HD 141569 from CHARA spectro-interferometry

    NASA Astrophysics Data System (ADS)

    Mendigutía, I.; Oudmaijer, R. D.; Mourard, D.; Muzerolle, J.

    2016-10-01

    This work presents CHARA/VEGA Hα spectro-interferometry (R ˜ 6000, and λ/2B ˜ 1 mas) of HD 179218 and HD 141569, doubling the sample of Herbig Ae/Be (HAeBe) stars for which this type of observations is available so far. The observed Hα emission is spatially unresolved, indicating that the size of the Hα emitting region is smaller than ˜ 0.21 and 0.12 au for HD 179218 and HD 141529 (˜ 15 and 16 R★, respectively). This is smaller than for the two other HAeBes previously observed with the same instrumentation. Two different scenarios have been explored in order to explain the compact line emitting regions. A hot, several thousand K, blackbody disc is consistent with the observations of HD 179218 and HD 141569. Magnetospheric accretion (MA) is able to reproduce the bulk of the Hα emission shown by HD 179218, confirming previous estimates from MA shock modelling with a mass accretion rate of 10-8 M⊙ yr-1, and an inclination to the line of sight between 30 and 50°. The Hα profile of HD 141569 cannot be fitted from MA due to the high rotational velocity of this object. Putting the CHARA sample together, a variety of scenarios is required to explain the Hα emission in HAeBe stars -compact or extended, discs, accretion, and winds-, in agreement with previous Brγ spectro-interferometric observations.

  15. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown).

    PubMed

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona Jm; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to "light on." The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The "dark" IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways. PMID:26382914

  16. Sequential expression and cooperative interaction of c-Ha-ras and c-erbB genes in in vivo chemical carcinogenesis

    SciTech Connect

    Husain, Z.; Fei, Y.; Roy, S.; Biswas, D.K. ); Solt, D.B.; Polverini, P.J. )

    1989-02-01

    The level of expression of several cellular protooncogenes is examined at different stages of 7,12-dimethylbenzanthracene (DMBA)-induced tumor development in hamster buccal pouch epithelium (HBPE). Results presented demonstrate overexpression of c-Ha-ras gene at a very early stage of tumor development, and this elevated level of expression of the gene persists throughout the tumorigenesis process. The expression of the cellular protooncogene c-erbB, on the other hand, can be detected only after 8-10 weeks of DMBA treatment of the tissue and increases with the progression of the disease. The overexpression of c-erbB gene can be correlated with the stage of extensive proliferation and subsequent invasion of the HBPE cells into the underlying connective tissue. This sequential pattern of stage-specific expression of the two cellular protooncogenes can be observed in (i) treated tissues, (ii) stage-representative cultured cells, and (iii) NIH 3T3 transformants derived with DNA from HBPE cells. The sequential overexpression of c-Ha-ras and c-erbB genes in a stage-specific manner and their cooperative interaction in the DMBA-induced in vivo oral carcinogenesis have been demonstrated.

  17. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown).

    PubMed

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona Jm; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to "light on." The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The "dark" IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways.

  18. Antioxidant Activity of Hawaiian Marine Algae

    PubMed Central

    Kelman, Dovi; Posner, Ellen Kromkowski; McDermid, Karla J.; Tabandera, Nicole K.; Wright, Patrick R.; Wright, Anthony D.

    2012-01-01

    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. PMID:22412808

  19. Carotenoids in algae: distributions, biosyntheses and functions.

    PubMed

    Takaichi, Shinichi

    2011-01-01

    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 b(6)f 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.

  20. SCALE FORMATION IN CHRYSOPHYCEAN ALGAE

    PubMed Central

    Brown, R. Malcolm; Franke, Werner W.; Kleinig, Hans; Falk, Heinz; Sitte, Peter

    1970-01-01

    The cell wall of the marine chrysophycean alga Pleurochrysis scherfellii is composed of distinct wall fragments embedded in a gelatinous mass. The latter is a polysaccharide of pectic character which is rich in galactose and ribose. These wall fragments are identified as scales. They have been isolated and purified from the vegetative mother cell walls after zoospore formation. Their ultrastructure is described in an electron microscope study combining sectioning, freeze-etch, and negative staining techniques. The scales consist of a layer of concentrically arranged microfibrils (ribbons with cross-sections of 12 to 25 x 25 to 40 A) and underlying radial fibrils of similar dimensions. Such a network-plate is densely coated with particles which are assumed to be identical to the pectic component. The microfibrils are resistant to strong alkaline treatment and have been identified as cellulose by different methods, including sugar analysis after total hydrolysis, proton resonance spectroscopical examination (NMR spectroscopy) of the benzoylated product, and diverse histochemical tests. The formation and secretion of the scales can be followed along the maturing Golgi cisternae starting from a pronounced dilated "polymerization center" as a completely intracisternal process which ends in the exocytotic extrusion of the scales. The scales reveal the very same ultrastructure within the Golgi cisternae as they do in the cell wall. The present finding represents the first evidence on cellulose formation by the Golgi apparatus and is discussed in relation to a basic scheme for cellulose synthesis in plant cells in general. PMID:5513606

  1. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats

    PubMed Central

    Holzinger, Andreas; Allen, Michael C.; Deheyn, Dimitri D.

    2016-01-01

    Snow algae and green algae living in aeroterrestrial habitats are ideal obbjects 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 charopyhte green algae (Zygnema sp., Zygogonium ericetorum and Klebsormidium crenulatum). The hyperspectral microscopic mapping and imaging technique allowed us to acquire total absorbance spectra of these microalgae in the waveband of 400-900 nm. Particularly in Chlamydomonas nivalis and Chlainomonas sp., a high absorbance in the wave band of 400-550 nm was observed, due to naturally occurring secondary carotenoids; in Chloromonas sp. and in the charopyhte algae this 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 not change the spectral properties, in the charopyhte algae the condensation of the cytoplasm and plastids increased the absorbance in the lower waveband of 400 – 500 nm. 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. PMID:27442511

  2. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    PubMed

    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. PMID:27442511

  3. Hyperspectral imaging of snow algae and green algae from aeroterrestrial habitats.

    PubMed

    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.

  4. PPR proteins of green algae.

    PubMed

    Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

    2013-01-01

    Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome.

  5. PPR proteins of green algae

    PubMed Central

    Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

    2013-01-01

    Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome. PMID:24021981

  6. [Algae removal of high algae raw water by coagulation enhanced by ozonation].

    PubMed

    Liu, Hai-Long; Yang, Dong; Zhao, Zhi-Yong; Li, Zheng-Jian; Cheng, Fang-Qin

    2009-07-15

    Apparent molecular weight distribution (AMWD) and resin fractionation were used to characterize organic matters of the raw water. Removal of algae, change and removal of dissolved organic carbon (DOC), disinfection by products (DBPs) control during the preozonation enhanced coagulation treatments in the jar-scale and pilot-scale experiment were studied. Algae activity (AA) was measured and used to elucidate the mechanisms of algae removal by above treatments. Results show that algae removal can be improved distinctively by proper preozonation, as the ozone dose 1.0 mg x L(-1), for instance. Algae removal could be increased from 55%-85% by traditional coagulation to 95% by enhanced coagulation after preozonation; and the best removal achieved 99.3% with ozone 1.0 mg x L(-1) and PACl 3.0 mg x L(-1); the residual THMFP (Trihalomethanes formation potential) was lowered from 117 microg x L(-1) by traditional coagulation to 46 microg x L(-1). But higher dose of ozone (as > or = 2.0 mg x L(-1)) impairs organic matter removal, although it decreases algae activity further. Significant differences were found in algae removal by AA detection between ozonation and traditional coagulation. Traditional coagulation had little effect on AA no matter the different PAC1 doses; while AA decreased clearly after ozonation. AA was lowered below 12 under 0.5-2.0 mg x L(-1) ozonation; and it kept decreasing with increase of ozone dosage. During the following coagulation, coagulant or some of its hydrolysised components enhanced the AA decrease by ozonation. Compared to the method of normal microscopy counting, AA test expresses the influence of algae living state by water treatment processes more clearly; which would provide treatment process designer with more distinct information about algae removal mechanisms and how to arrange the treatment processes to improve algae removal.

  7. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements.

  8. Studies on marine algae for haemagglutinic activity.

    PubMed

    Alam, M T; Usmanghani, K

    1994-07-01

    Lectins (agglutinins) are important in medical and immunological applications. Phytohaemagglutinins have been found useful in blood banking. Keeping in view of these facts, the marine algae found at Karachi coastal region have been screened for agglutinic activity by using human erythrocytes of A, B, AB and 0 group. Altogether 53 algal samples were collected and subjected to extraction, fractionation serial dilution and titre determinations. The total marine algae screened for haemagglutinic activity were 44 out of these 14, 13 and 17 belonged to Chlorophyta, Phaeophyta, and Rhodophyta respectively. Among these three groups the Rhodophyta showed the highest number of lytic activity. The green marine alga Valoniopsis pachynema showed a titre value between 2(2) and 2(3), which is statistically significant. In case of brown marine algae Colpomenia sinuosa was found to be active (titre 2(3)), while Dictyota dichotoma, D. indica and Iyengaria stellata, furnished week titre value as 2(2). The red marine algae screened were 17, out of these 4 spp. showed significant activity (titre 2(3)), and these are Gelidium usmanghani, Gracilaria foliifera Hypnea pannosa and Hynea valentiae. While Scinaia fascicularis, Scinaia indica and Champia parvula were found to be weak in their onset on human erythrocytes. The results obtained were quite in agreement with those reported in the literature. PMID:16414751

  9. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. PMID:20547408

  10. Controlled regular locomotion of algae cell microrobots.

    PubMed

    Xie, Shuangxi; Jiao, Niandong; Tung, Steve; Liu, Lianqing

    2016-06-01

    Algae cells can be considered as microrobots from the perspective of engineering. These organisms not only have a strong reproductive ability but can also sense the environment, harvest energy from the surroundings, and swim very efficiently, accommodating all these functions in a body of size on the order of dozens of micrometers. An interesting topic with respect to random swimming motions of algae cells in a liquid is how to precisely control them as microrobots such that they swim according to manually set routes. This study developed an ingenious method to steer swimming cells based on the phototaxis. The method used a varying light signal to direct the motion of the cells. The swimming trajectory, speed, and force of algae cells were analyzed in detail. Then the algae cell could be controlled to swim back and forth, and traverse a crossroad as a microrobot obeying specific traffic rules. Furthermore, their motions along arbitrarily set trajectories such as zigzag, and triangle were realized successfully under optical control. Robotize algae cells can be used to precisely transport and deliver cargo such as drug particles in microfluidic chip for biomedical treatment and pharmacodynamic analysis. The study findings are expected to bring significant breakthrough in biological drives and new biomedical applications.

  11. Estimation of alga growth stage and lipid content growth rate

    NASA Technical Reports Server (NTRS)

    Embaye, Tsegereda N. (Inventor); Trent, Jonathan D. (Inventor)

    2012-01-01

    Method and system for estimating a growth stage of an alga in an ambient fluid. Measured light beam absorption or reflection values through or from the alga and through an ambient fluid, in each of two or more wavelength sub-ranges, are compared with reference light beam absorption values for corresponding wavelength sub-ranges for in each alga growth stage to determine (1) which alga growth stage, if any, is more likely and (2) whether estimated lipid content of the alga is increasing or has peaked. Alga growth is preferably terminated when lipid content has approximately reached a maximum value.

  12. Genome of the red alga Porphyridium purpureum.

    PubMed

    Bhattacharya, Debashish; Price, Dana C; Chan, Cheong Xin; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P M; Arias, Maria Cecilia; Henrissat, Bernard; Coutinho, Pedro M; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life.

  13. Algae control problems and practices workshop

    SciTech Connect

    Pryfogle, P.A.; Ghio, G.

    1996-09-01

    Western water resources are continuously facing increased demand from industry and the public. Consequently, many of these resources are required to perform multiple tasks as they cycle through the ecosystem. Many plants and animals depend upon these resources for growth. Algae are one group of plants associated with nutrient and energy cycles in many aquatic ecosystems. Although most freshwater algae are microscopic in size, they are capable of dominating and proliferating to the extent that the value of the water resource for both industrial and domestic needs is compromised. There is a great diversity of aquatic environments and systems in which algae may be found, and there are many varieties of treatment and control techniques available to reduce the impacts of excessive growth. This workshop was organized to exchange information about these control problems and practices.

  14. Genome of the red alga Porphyridium purpureum

    PubMed Central

    Bhattacharya, Debashish; Price, Dana C.; Xin Chan, Cheong; Qiu, Huan; Rose, Nicholas; Ball, Steven; Weber, Andreas P. M.; Cecilia Arias, Maria; Henrissat, Bernard; Coutinho, Pedro M.; Krishnan, Anagha; Zäuner, Simone; Morath, Shannon; Hilliou, Frédérique; Egizi, Andrea; Perrineau, Marie-Mathilde; Yoon, Hwan Su

    2013-01-01

    The limited knowledge we have about red algal genomes comes from the highly specialized extremophiles, Cyanidiophyceae. Here, we describe the first genome sequence from a mesophilic, unicellular red alga, Porphyridium purpureum. The 8,355 predicted genes in P. purpureum, hundreds of which are likely to be implicated in a history of horizontal gene transfer, reside in a genome of 19.7 Mbp with 235 spliceosomal introns. Analysis of light-harvesting complex proteins reveals a nuclear-encoded phycobiliprotein in the alga. We uncover a complex set of carbohydrate-active enzymes, identify the genes required for the methylerythritol phosphate pathway of isoprenoid biosynthesis, and find evidence of sexual reproduction. Analysis of the compact, function-rich genome of P. purpureum suggests that ancestral lineages of red algae acted as mediators of horizontal gene transfer between prokaryotes and photosynthetic eukaryotes, thereby significantly enriching genomes across the tree of photosynthetic life. PMID:23770768

  15. Turning Algae into Energy in New Mexico

    ScienceCinema

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2016-07-12

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  16. Turning Algae into Energy in New Mexico

    SciTech Connect

    Sayre, Richard; Olivares, Jose; Lammers, Peter

    2013-07-29

    Los Alamos National Laboratory, as part of the New Mexico Consortium - comprised of New Mexico's major research universities, the Lab, and key industry partners - is conducting research into using algae as a feed stock for a renewable source of fuels, and other products. There are hundreds of thousands of different algae species on Earth. They account for approximately half of the net photosynthesis on the planet, yet they have not been used in any kind of a large scale by humanity, with just a few exceptions. And yet, the biomass is easy to transform into useful products, including fuels, and they contain many other natural products that have high value. In this video Los Alamos and New Mexico State University scientists outline the opportunities and challenges of using science to turn algae into energy.

  17. Microspectroscopy of the photosynthetic compartment of algae.

    PubMed

    Evangelista, Valtere; Frassanito, Anna Maria; Passarelli, Vincenzo; Barsanti, Laura; Gualtieri, Paolo

    2006-01-01

    We performed microspectroscopic evaluation of the pigment composition of the photosynthetic compartments of algae belonging to different taxonomic divisions and higher plants. The feasibility of microspectroscopy for discriminating among species and/or phylogenetic groups was tested on laboratory cultures. Gaussian bands decompositions and a fitting algorithm, together with fourth-derivative transformation of absorbance spectra, provided a reliable discrimination among chlorophylls a, b and c, phycobiliproteins and carotenoids. Comparative analysis of absorption spectra highlighted the evolutionary grouping of the algae into three main lineages in accordance with the most recent endosymbiotic theories.

  18. Mean angular diameters, distances, and pulsation modes of the classical Cepheids FF Aquilae and T Vulpeculae. CHARA/FLUOR near-infrared interferometric observations

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Kervella, P.; Mérand, A.; McAlister, H.; ten Brummelaar, T.; Coudé du Foresto, V.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2012-05-01

    We report the first angular diameter measurements of two classical Cepheids, FF Aql and T Vul, that we obtain using observations with the FLUOR instrument installed at the CHARA interferometric array. We derive average limb-darkened angular diameters of θLD = 0.878 ± 0.013 mas and θLD = 0.629 ± 0.013 mas, respectively, for FF Aql and T Vul. Combining these angular diameters with the HST-FGS trigonometric parallaxes leads to linear radii R = 33.6 ± 2.2 R⊙ and R = 35.6 ± 4.4 R⊙, respectively. The comparison with empirical and theoretical period-radius relations leads to the conclusion that these Cepheids are pulsating in their fundamental mode. The knowledge of this pulsation mode is of prime importance to calibrating the period-luminosity relation with a uniform sample of fundamental mode Cepheids.

  19. WASP7 BENTHIC ALGAE - MODEL THEORY AND USER'S GUIDE

    EPA Science Inventory

    The standard WASP7 eutrophication module includes nitrogen and phosphorus cycling, dissolved oxygen-organic matter interactions, and phytoplankton kinetics. In many shallow streams and rivers, however, the attached algae (benthic algae, or periphyton, attached to submerged substr...

  20. MANOMETRIC MEASUREMENTS OF PHOTOSYNTHESIS IN THE MARINE ALGA GIGARTINA

    PubMed Central

    Emerson, Robert; Green, Lowell

    1934-01-01

    A manometric method for measuring photosynthesis in marine algae is described. Photosynthesis in the red alga Gigartina harveyana is shown to be similar in all important respects to photosynthesis in Chlorella and other Chlorophyceae. PMID:19872816

  1. An Overview of Algae Biofuel Production and Potential Environmental Impact

    EPA Science Inventory

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas)...

  2. [Accumulation of polycyclic arenes in Baltic Sea algae].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Kukk, Kh A

    1985-01-01

    The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Käsmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf.

  3. [Accumulation of polycyclic arenes in Baltic Sea algae].

    PubMed

    Veldre, I A; Itra, A R; Paal'me, L P; Kukk, Kh A

    1985-01-01

    The paper presents data on the level of benzo(a)pyrene (BP) and some other polycyclic arenes in alga and phanerogam specimens from different gulfs of the Baltic Sea. Algae were shown to absorb BP from sea water. The mean concentration of BP in sea water was under 0.004 microgram/1, while in algae it ranged 0.1-21.2 micrograms/kg dry weight. Algae accumulate BP to a higher degree than phanerogams. The highest concentrations of BP were found in algae Enteromorpha while the lowest ones in Furcellaria. In annual green algae, BP level was higher in autumn, i. e. at the end of vegetation period, than in spring. Brown algae Fucus vesiculosus is recommended for monitoring polycyclic arene pollution in the area from Vormsi Island to Käsmu and green algae Cladophora or Enteromorpha in the eastern part of the Finnish Gulf. PMID:4060672

  4. Use of Brown Algae to Demonstrate Natural Products Techniques.

    ERIC Educational Resources Information Center

    Porter, Lee A.

    1985-01-01

    Background information is provided on the natural products found in marine organisms in general and the brown algae in particular. Also provided are the procedures needed to isolate D-mannitol (a primary metabolite) and cholesterol from brown algae. (JN)

  5. Time, spatial, and spectral resolution of the Hα line-formation region of Deneb and Rigel with the VEGA/CHARA interferometer

    NASA Astrophysics Data System (ADS)

    Chesneau, O.; Dessart, L.; Mourard, D.; Bério, Ph.; Buil, Ch.; Bonneau, D.; Borges Fernandes, M.; Clausse, J. M.; Delaa, O.; Marcotto, A.; Meilland, A.; Millour, F.; Nardetto, N.; Perraut, K.; Roussel, A.; Spang, A.; Stee, P.; Tallon-Bosc, I.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

    2010-10-01

    Context. BA-type supergiants are amongst the most optically-bright stars. They are observable in extragalactic environments, hence potential accurate distance indicators. Aims: An extensive record of emission activity in the Hα line of the BA supergiants β Orionis (Rigel, B8Ia) and α Cygni (Deneb, A2Ia) is indicative of localized time-dependent mass ejections. However, little is known about the spatial distribution of these apparent structures. Here, we employ optical interferometry to study the Hα line-formation region in these stellar environments. Methods: High spatial- ( 0.001'') and spectral- (R = 30 000) resolution observations of Hα were obtained with the visible recombiner VEGA installed on the CHARA interferometer, using the S1S2 array-baseline (34 m). Six independent observations were done on Deneb during the years 2008 and 2009, and two of Rigel in 2009. We analyze this dataset with the 1D non-LTE radiative-transfer code cmfgen, and assess the impact of the wind on the visible and near-IR interferometric signatures, using both Balmer-line and continuum photons. Results: We observe a visibility decrease in Hα for both Rigel and Deneb, suggesting that the line-formation region is extended ( 1.5-1.75 Rstar). We observe a significant visibility decrease for Deneb in the Siii 6371 Å line. We witness time variations in the differential phase for Deneb, implying an inhomogeneous and unsteady circumstellar environment, while no such variability is seen in differential visibilities. Radiative-transfer modeling of Deneb, with allowance for stellar-wind mass loss, accounts fairly well for the observed decrease in the Hα visibility. Based on the observed differential visibilities, we estimate that the mass-loss rate of Deneb has changed by less than 5%. Based on observations made with the CHARA array.

  6. Circadian changes in endogenous concentrations of indole-3-acetic acid, melatonin, serotonin, abscisic acid and jasmonic acid in Characeae (Chara australis Brown)

    PubMed Central

    Beilby, Mary J; Turi, Christina E; Baker, Teesha C; Tymm, Fiona JM; Murch, Susan J

    2015-01-01

    Giant-celled Characeae (Chara australis Brown), grown for 4 months on 12/12 hr day/night cycle and summer/autumn temperatures, exhibited distinct concentration maxima in auxin (indole-3-acetic acid; IAA), melatonin and serotonin about 4 hr after subjective daybreak. These concentration peaks persisted after 3 day pretreatment in continuous darkness: confirming a circadian rhythm, rather than a response to “light on.” The plants pretreated for 3 d in continuous light exhibited several large IAA concentration maxima throughout the 24 hr. The melatonin and serotonin concentrations decreased and were less synchronized with IAA. Chara plants grown on 9/15 hr day/night cycle for 4 months and winter/spring temperatures contained much smaller concentrations of IAA, melatonin and serotonin. The IAA concentration maxima were observed in subjective dark phase. Serotonin concentration peaks were weakly correlated with those of IAA. Melatonin concentration was low and mostly independent of circadian cycle. The “dark” IAA concentration peaks persisted in plants treated for 3 d in the dark. The plants pretreated for 3 d in the light again developed more IAA concentration peaks. In this case the concentration maxima in melatonin and serotonin became more synchronous with those in IAA. The abscisic acid (ABA) and jasmonic acid (JA) concentrations were also measured in plants on winter regime. The ABA concentration did not exhibit circadian pattern, while JA concentration peaks were out of phase with those of IAA. The data are discussed in terms of crosstalk between metabolic pathways. PMID:26382914

  7. Neonatal sepsis caused by Shewanella algae: A case report.

    PubMed

    Charles, Marie Victor Pravin; Srirangaraj, Sreenivasan; Kali, Arunava

    2015-01-01

    Sepsis remains a leading cause of mortality among neonates, especially in developing countries. Most cases of neonatal sepsis are attributed to Escherichia coli and other members of the Enterobacteriaceae family. Shewanella algae (S. algae) is a gram-negative saprophytic bacillus, commonly associated with the marine environment, which has been isolated from humans. Early onset neonatal sepsis caused by S. algae is uncommon. We report a case of S. algae blood stream infection in a newborn with early onset neonatal sepsis.

  8. Profiles of antioxidant/electrophile response element (ARE/EpRE) nuclear protein binding and c-Ha-ras transactivation in vascular smooth muscle cells treated with oxidative metabolites of benzo[a]pyrene.

    PubMed

    Miller, K P; Chen, Y H; Hastings, V L; Bral, C M; Ramos, K S

    2000-11-01

    Activation of nuclear protein binding to the antioxidant/electrophile response element (ARE/EpRE) by benzo[a]pyrene (BaP) in vascular smooth muscle cells (vSMCs) is associated with transcriptional deregulation of c-Ha-ras. This response may be mediated by oxidative intermediates of BaP generated during the course of cellular metabolism. To test this hypothesis, the profile of ARE/EpRE protein binding and transactivation elicited by BaP was compared with that of 3-hydroxy BaP (3-OH BaP) (0.03 to 3.0 microM), BaP 7,8-dihydrodiol (BaP 7,8-diol) (0.03 to 3.0 microM), BaP 3,6-quinone (BaP 3,6-Q) (0.0003 to 3.0 microM), and H(2)O(2) (25 to 100 microM). Specific protein binding to the consensus c-Ha-ras ARE/EpRE was observed in vSMCs treated with all BaP metabolites at concentrations considerably lower than those required for the parent compound. H(2)O(2), a by-product of BaP 3,6-Q redox cycling, also increased binding to the ARE/EpRE. Treatment of vSMCs with oxidative BaP metabolites or H(2)O(2) transactivated the c-Ha-ras promoter in all instances, but the response was consistently half of the maximal induction elicited by BaP. Similar proteins cross-linked specifically to the consensus c-Ha-ras ARE/EpRE sequence in cells treated with BaP or its oxidative intermediates. The protein binding profile in the c-Ha-ras promoter was similar to that in the NADPH:quinone reductase gene (NQO(1)) and the glutathione S-transferase Ya gene (GSTYa) promoters, but the relative abundance of individual complexes was promoter-specific. We conclude that oxidative intermediates of BaP mediate activation of nuclear protein binding to ARE/EpRE and contribute to transcriptional de-regulation of c-Ha-ras in vSMCs.

  9. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2010 CFR

    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...

  10. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 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...

  11. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 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...

  12. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 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...

  13. 21 CFR 73.185 - Haematococcus algae meal.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 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...

  14. How to Identify and Control Water Weeds and Algae.

    ERIC Educational Resources Information Center

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  15. Research and development for algae-based technologies in Korea: a review of algae biofuel production.

    PubMed

    Hong, Ji Won; Jo, Seung-Woo; Yoon, Ho-Sung

    2015-03-01

    This review covers recent research and development (R&D) activities in the field of algae-based biofuels in Korea. As South Korea's energy policy paradigm has focused on the development of green energies, the government has funded several algae biofuel R&D consortia and pilot projects. Three major programs have been launched since 2009, and significant efforts are now being made to ensure a sustainable supply of algae-based biofuels. If these R&D projects are executed as planned for the next 10 years, they will enable us to overcome many technical barriers in algae biofuel technologies and help Korea to become one of the leading countries in green energy by 2020.

  16. Spirulina: The Alga That Can End Malnutrition.

    ERIC Educational Resources Information Center

    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)

  17. Fucoidans — sulfated polysaccharides of brown algae

    NASA Astrophysics Data System (ADS)

    Usov, Anatolii I.; Bilan, M. I.

    2009-08-01

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  18. Pheromone signaling during sexual reproduction in algae.

    PubMed

    Frenkel, Johannes; Vyverman, Wim; Pohnert, Georg

    2014-08-01

    Algae are found in all aquatic and many terrestrial habitats. They are dominant in phytoplankton and biofilms thereby contributing massively to global primary production. Since algae comprise photosynthetic representatives of the various protoctist groups their physiology and appearance is highly diverse. This diversity is also mirrored in their characteristic life cycles that exhibit various facets of ploidy and duration of the asexual phase as well as gamete morphology. Nevertheless, sexual reproduction in unicellular and colonial algae usually has as common motive that two specialized, sexually compatible haploid gametes establish physical contact and fuse. To guarantee mating success, processes during sexual reproduction are highly synchronized and regulated. This review focuses on sex pheromones of algae that play a key role in these processes. Especially, the diversity of sexual strategies as well as of the compounds involved are the focus of this contribution. Discoveries connected to algal pheromone chemistry shed light on the role of key evolutionary processes, including endosymbiotic events and lateral gene transfer, speciation and adaptation at all phylogenetic levels. But progress in this field might also in the future provide valid tools for the manipulation of aquaculture and environmental processes.

  19. Laser-fluorescence measurement of marine algae

    NASA Technical Reports Server (NTRS)

    Browell, E. V.

    1980-01-01

    Progress in remote sensing of algae by laser-induced fluorescence is subject of comprehensive report. Existing single-wavelength and four-wavelength systems are reviewed, and new expression for power received by airborne sensor is derived. Result differs by as much as factor of 10 from those previously reported. Detailed error analysis evluates factors affecting accuracy of laser-fluorosensor systems.

  20. Peroxisomal targeting signals in green algae.

    PubMed

    Shinozaki, Akiko; Sato, Nagisa; Hayashi, Yasuko

    2009-03-01

    Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP-PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3'-diaminobenzidine. Our results confirm that the GFP-PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells.

  1. Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

    PubMed

    Zherelova, Olga M; Kataev, Anatoly A; Grishchenko, Valery M; Knyazeva, Ekaterina L; Permyakov, Sergei E; Permyakov, Eugene A

    2009-06-01

    The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles. Calcium association decreases protein affinity to the vesicles; the effect being less pronounced for LA-OA-17. The voltage clamp technique studies show that LA-OA-17, HAMLET, and their constituents produce different modifying effects on the plasmalemmal ionic channels of the Chara corallina cells. The irreversible binding of OA-complexes to the plasmalemma is accompanied by changes in the activation-inactivation kinetics of developing integral transmembrane currents, suppression of the Ca(2+) current and Ca(2+)-activated Cl(-) current, and by increase in the nonspecific K(+) leakage currents. The latter reflects development of nonselective permeability of the plasma membrane. The HAMLET-induced effects on the plasmalemmal currents are less pronounced and potentiated by LA-OA-17. The control experiments with OA and intact alpha-LA show their qualitatively different and much less pronounced effects on the transmembrane ionic currents. Thus, the modification of alpha-LA by OA results in an increase in the protein association with the model lipid bilayer and in drastic irreversible changes in permeability of several types of the plasmalemmal ionic channels.

  2. Interaction of antitumor alpha-lactalbumin-oleic acid complexes with artificial and natural membranes.

    PubMed

    Zherelova, Olga M; Kataev, Anatoly A; Grishchenko, Valery M; Knyazeva, Ekaterina L; Permyakov, Sergei E; Permyakov, Eugene A

    2009-06-01

    The specific complexes of human alpha-lactalbumin (alpha-LA) with oleic acid (OA), HAMLET and LA-OA-17 (OA-complexes), possess cytotoxic activity against tumor cells but the mechanism of their cell penetration remains unclear. To explore the molecular mechanisms underlying interaction of the OA-complexes with the cell membrane, their interactions with small unilamellar dipalmitoylphosphatidylcholine (DPPC) vesicles and electroexcitable plasma membrane of internodal native and perfused cells of the green alga Chara corallina have been studied. The fractionation (Sephadex G-200) of mixtures of the OA-complexes with the vesicles shows that OA-binding increases the affinity of alpha-LA to DPPC vesicles. Calcium association decreases protein affinity to the vesicles; the effect being less pronounced for LA-OA-17. The voltage clamp technique studies show that LA-OA-17, HAMLET, and their constituents produce different modifying effects on the plasmalemmal ionic channels of the Chara corallina cells. The irreversible binding of OA-complexes to the plasmalemma is accompanied by changes in the activation-inactivation kinetics of developing integral transmembrane currents, suppression of the Ca(2+) current and Ca(2+)-activated Cl(-) current, and by increase in the nonspecific K(+) leakage currents. The latter reflects development of nonselective permeability of the plasma membrane. The HAMLET-induced effects on the plasmalemmal currents are less pronounced and potentiated by LA-OA-17. The control experiments with OA and intact alpha-LA show their qualitatively different and much less pronounced effects on the transmembrane ionic currents. Thus, the modification of alpha-LA by OA results in an increase in the protein association with the model lipid bilayer and in drastic irreversible changes in permeability of several types of the plasmalemmal ionic channels. PMID:19588235

  3. Widespread occurrence of norspermidine and norspermine in eukaryotic algae.

    PubMed

    Hamana, K; Matsuzaki, S

    1982-04-01

    Seven phyla of eukaryotic algae were analyzed to determine their contents of diamines and polyamines. The algae examined included Rhodophyta, Pyrrophyta, Chrysophyta, Phaeophyta, Euglenophyta, Chlorophyta, and Charophyta. Both putrescine and spermidine were detected in all the algae studied, while appreciable amounts of spermine were detected only in a few species of algae. 1,3-Diaminopropane, norspermidine, and norspermine, which are chemical analogs of putrescine, spermidine, and spermine, respectively, were widely distributed in various species of algae. There was no parallelism between the distribution patterns of putrescine derivatives and those of 1,3-diaminopropane derivatives. Cadaverine and agmatine were detected in multicellular marine algae. Homospermidine was detected sporadically in some algae. The biological and phylogenetical significance of polyamines in these lower eukaryotes is discussed.

  4. Sulfated polysaccharides as bioactive agents from marine algae.

    PubMed

    Ngo, Dai-Hung; Kim, Se-Kwon

    2013-11-01

    Recently, much attention has been paid by consumers toward natural bioactive compounds as functional ingredients in nutraceuticals. Marine algae are considered as valuable sources of structurally diverse bioactive compounds. Marine algae are rich in sulfated polysaccharides (SPs) such as carrageenans in red algae, fucoidans in brown algae and ulvans in green algae. These SPs exhibit many health beneficial nutraceutical effects such as antioxidant, anti-allergic, anti-human immunodeficiency virus, anticancer and anticoagulant activities. Therefore, marine algae derived SPs have great potential to be further developed as medicinal food products or nutraceuticals in the food industry. This contribution presents an overview of nutraceutical effects and potential health benefits of SPs derived from marine algae.

  5. Identification of a provirally activated c-Ha-ras oncogene in an avian nephroblastoma via a novel procedure: cDNA cloning of a chimaeric viral-host transcript.

    PubMed Central

    Westaway, D; Papkoff, J; Moscovici, C; Varmus, H E

    1986-01-01

    Retrovirus without oncogenes often exert their neoplastic potential as insertional mutagens of cellular proto-oncogenes. This may be associated with the production of chimaeric viral-host transcripts; in these cases; activated cellular genes can be identified by obtaining cDNA clones of bipartite RNAs. This approach was used in the analysis of chicken nephroblastomas induced by myeloblastosis-associated virus (MAV). One tumor contained a novel mRNA species initiated within a MAV LTR. cDNA cloning revealed that this mRNA encodes a protein of 189 amino acids, identical to that of normal human Ha-ras-1 at 185 positions, including positions implicated in oncogenic activation of ras proto-oncogenes; there are no differences between the coding sequences of presumably normal Ha-ras cDNA clones from chicken lymphoma RNA and the tumor-derived cDNAs. The chimaeric mRNA in the nephroblastoma is at least 25-fold more abundant than c-Ha-ras mRNA in normal kidney tissue, and a 21-kd ras-related protein is present in relatively large amounts in the tumor. We conclude that a quantitative change in c-Ha-ras gene expression results from an upstream insertion mutation and presumably contributes to tumorigenesis in this single case. Little or no increase in c-Ha-ras RNA or protein was observed in other nephroblastomas. Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 10. PMID:3011401

  6. Photooxidative Death in Blue-Green Algae

    PubMed Central

    Abeliovich, A.; Shilo, M.

    1972-01-01

    When incubated in the light under 100% oxygen, wild-type blue-green algae (Anacystis nidulans, Synechococcus cedrorum) die out rapidly at temperatures of 4 to 15 C, and at 35 C (or at 26 C in the case of S. cedrorum) in the absence of CO2. Photosynthesis is impaired in these cells long before they die. Blocking of photosystem II at high temperatures in the presence of CO2 sensitizes the algae to photooxidative death. Photooxidative death and bleaching of photosynthetic pigments are separable phenomena. Photooxidative conditions were demonstrated in Israeli fish ponds using A. nidulans as the test organism during dense summer blooms, when dissolved CO2 is low, and in winter, when water temperatures generally drop below 15 C. This finding suggests that photooxidative death may be responsible for the sudden decomposition of blue-green blooms in summer, and may be a factor in the absence of blue-green blooms in winter. PMID:4626540

  7. Phycobilisomes in Blue-Green Algae

    PubMed Central

    Wildman, Ruth B.; Bowen, C. C.

    1974-01-01

    Fifteen species of freshwater blue-green algae, including unicellular, filamentous, and colonial forms, were subjected to a variety of fixatives, fixation conditions, and stains for comparison of the preservation of phycobilisomes. Absorption spectra of the corresponding in vivo and released photosynthetic pigments, in 10 of the species that were maintained in culture, demonstrated the presence of phycocyanin in all 10 species and phycoerythrin in only 2 of them. Spectroscope and electron microscope evidence was obtained for localization of phycobiliproteins in phycobilisomes of Nostoc muscorum. Phycobilisomes were observed in all species examined in situ, strenghening the hypothesis that phycobilisomes are common to all phycobiliprotein-containing photosynthetic blue-green algae. Images PMID:4204443

  8. Toxicity of chlorinated benzenes to marine algae

    NASA Astrophysics Data System (ADS)

    Ma, Yan-Jun; Wang, Xiu-Lin; Yu, Wei-Jun; Zhang, Li-Jun; Sun, Han-Zhang

    1997-12-01

    Growth of Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to monochlorobenzene (MCB), 1,2-dichlorobenzene (1,2-DCB), 1, 2, 3, 4-tetrachlorobenzene (1, 2, 3, 4-TeCB) and pentachlorobenzene (PeCB) was tested. Tests of 72 h- EC 50 values showed that the toxicity ranged in the order: MCB<1,2-DCB<1,2,3,4-TeCBalgae was almost in the order: Pyramidomonas sp. < Platymonas subcordiformis < Nannochloropsis oculata < Chlorella marine < Phaeodactylum tricomutum. Study of the QSAR (Quantitative Structure-Activity Relationship) between K OW and toxicity of CBs to marine algae showed good relationships between -log EC 50 and log K OW.

  9. Bioconcentration of tetrachlorobenzene in marine algae

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Lin; Ma, Yan-Jun; Cheng, Gang; Yu, Wei-Jun; Zhang, Li-Jun

    1997-09-01

    Bioconcentration of tetrachlorobenzene (TeCB) in Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis, and Phaeodactylum tricornutum; and toxicity of TeCB to the marine algae were tested. Values of bioconcentration potential parameters, including uptake rate constant k 1, elimination rate constant k 2 and bioconcentration factor BCF, were obtained not only from the time course of TeCB uptake by the marine algae by using a bioconcentration model, but also from the acute toxicity test data for percent inhibition PI(%)˜exposure concentration of TeCB-time by using a combined bioconcentration and probability model. The results showed good relationship between k 1(TOXIC) and k 1(UPTAKE) and k 2(TOXIC), k 2(UPTAKE), and BCF D(IOXIC) and BCF D(UPTAKE). Especially, the values of BCF D(TOXIC) were well consistent with those of BCF D(UPTAKE).

  10. Biofuels from algae: challenges and potential

    PubMed Central

    Hannon, Michael; Gimpel, Javier; Tran, Miller; Rasala, Beth; Mayfield, Stephen

    2011-01-01

    Algae biofuels may provide a viable alternative to fossil fuels; however, this technology must overcome a number of hurdles before it can compete in the fuel market and be broadly deployed. These challenges include strain identification and improvement, both in terms of oil productivity and crop protection, nutrient and resource allocation and use, and the production of co-products to improve the economics of the entire system. Although there is much excitement about the potential of algae biofuels, much work is still required in the field. In this article, we attempt to elucidate the major challenges to economic algal biofuels at scale, and improve the focus of the scientific community to address these challenges and move algal biofuels from promise to reality. PMID:21833344

  11. Nitrogenous wastewater treatment by activated algae

    SciTech Connect

    Gupta, S.K.

    1985-02-01

    A biological treatability study by activated algae process was performed with synthetic wastewater containing a high concentration of nitrogen. It was found that the wastewater could be processed at all nitrogen removal rates. The yield coefficient and decay coefficient for heterotrophic bacteria were 0.06 (COD basis) and 0.019 day/sup -1/ (COD bases) respectively. The yield coefficient and decay coefficient for nitrifiers were 0.06 and 0.02 day/sup -1/ respectively. NH/sup +//sub 4/-N seemed to inhibit bacteriological growth as the yield coefficients values were significantly lower. Nitrification was observed at all the nitrogen loadings. Diffusion of NH/sub 3/ into the atmosphere was the dominant mechanism of nitrogen removal. The results demonstrated a symbiotic relationship between algae and bacteria.

  12. Fermentation metabolism and its evolution in algae

    PubMed Central

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C.; Grossman, Arthur R.

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume. PMID:23734158

  13. Selenium Uptake and Volatilization by Marine Algae

    NASA Astrophysics Data System (ADS)

    Luxem, Katja E.; Vriens, Bas; Wagner, Bettina; Behra, Renata; Winkel, Lenny H. E.

    2015-04-01

    Selenium (Se) is an essential trace nutrient for humans. An estimated one half to one billion people worldwide suffer from Se deficiency, which is due to low concentrations and bioavailability of Se in soils where crops are grown. It has been hypothesized that more than half of the atmospheric Se deposition to soils is derived from the marine system, where microorganisms methylate and volatilize Se. Based on model results from the late 1980s, the atmospheric flux of these biogenic volatile Se compounds is around 9 Gt/year, with two thirds coming from the marine biosphere. Algae, fungi, and bacteria are known to methylate Se. Although algal Se uptake, metabolism, and methylation influence the speciation and bioavailability of Se in the oceans, these processes have not been quantified under environmentally relevant conditions and are likely to differ among organisms. Therefore, we are investigating the uptake and methylation of the two main inorganic Se species (selenate and selenite) by three globally relevant microalgae: Phaeocystis globosa, the coccolithophorid Emiliania huxleyi, and the diatom Thalassiosira oceanica. Selenium uptake and methylation were quantified in a batch experiment, where parallel gas-tight microcosms in a climate chamber were coupled to a gas-trapping system. For E. huxleyi, selenite uptake was strongly dependent on aqueous phosphate concentrations, which agrees with prior evidence that selenite uptake by phosphate transporters is a significant Se source for marine algae. Selenate uptake was much lower than selenite uptake. The most important volatile Se compounds produced were dimethyl selenide, dimethyl diselenide, and dimethyl selenyl sulfide. Production rates of volatile Se species were larger with increasing intracellular Se concentration and in the decline phase of the alga. Similar experiments are being carried out with P. globosa and T. oceanica. Our results indicate that marine algae are important for the global cycling of Se

  14. Fermentation metabolism and its evolution in algae.

    PubMed

    Catalanotti, Claudia; Yang, Wenqiang; Posewitz, Matthew C; Grossman, Arthur R

    2013-01-01

    Fermentation or anoxic metabolism allows unicellular organisms to colonize environments that become anoxic. Free-living unicellular algae capable of a photoautotrophic lifestyle can also use a range of metabolic circuitry associated with different branches of fermentation metabolism. While algae that perform mixed-acid fermentation are widespread, the use of anaerobic respiration is more typical of eukaryotic heterotrophs. The occurrence of a core set of fermentation pathways among the algae provides insights into the evolutionary origins of these pathways, which were likely derived from a common ancestral eukaryote. Based on genomic, transcriptomic, and biochemical studies, anaerobic energy metabolism has been examined in more detail in Chlamydomonas reinhardtii (Chlamydomonas) than in any other photosynthetic protist. This green alga is metabolically flexible and can sustain energy generation and maintain cellular redox balance under a variety of different environmental conditions. Fermentation metabolism in Chlamydomonas appears to be highly controlled, and the flexible use of the different branches of fermentation metabolism has been demonstrated in studies of various metabolic mutants. Additionally, when Chlamydomonas ferments polysaccharides, it has the ability to eliminate part of the reductant (to sustain glycolysis) through the production of H2, a molecule that can be developed as a source of renewable energy. To date, little is known about the specific role(s) of the different branches of fermentation metabolism, how photosynthetic eukaryotes sense changes in environmental O2 levels, and the mechanisms involved in controlling these responses, at both the transcriptional and post-transcriptional levels. In this review, we focus on fermentation metabolism in Chlamydomonas and other protists, with only a brief discussion of plant fermentation when relevant, since it is thoroughly discussed in other articles in this volume.

  15. Algae-Derived Dietary Ingredients Nourish Animals

    NASA Technical Reports Server (NTRS)

    2015-01-01

    In the 1980s, Columbia, Maryland-based Martek Biosciences Corporation worked with Ames Research Center to pioneer the use of microalgae as a source of essential omega-3 fatty acids, work that led the company to develop its highly successful Formulaid product. Now the Nutritional Products Division of Royal DSM, the company also manufactures DHAgold, a nutritional supplement for pets, livestock and farm-raised fish that uses algae to deliver docosahexaenoic acid (DHA).

  16. Measuring the distribution of cellulose microfibril angles in primary cell walls by small angle X-ray scattering

    PubMed Central

    2014-01-01

    Background X-ray scattering is a well-established method for measuring cellulose microfibril angles in secondary cell walls. However, little data is available on the much thinner primary cell walls. Here, we show that microfibril orientation distributions can be determined by small angle X-ray scattering (SAXS) even in primary cell walls. The technique offers a number of advantages: samples can be analyzed in the native hydrated state without any preparation which minimizes the risk of artifacts and allows for fast data acquisition. The method provides data averaged over a specimen region, determined by the size of the used X-ray beam and, thus, yields the microfibril orientation distribution within this region. Results Cellulose microfibril orientation distributions were obtained for single cells of the alga Chara corallina, as well as for the multicellular hypocotyl of Arabidopsis thaliana. In both, Chara and Arabidopsis, distributions with a broad scattering around mean microfibril angles of approximately 0° and 90° towards the longitudinal axis of the cells were found. Conclusions With SAXS, the structure of primary cell walls can be analysed in their native state and new insights into the cellulose microfibril orientation of primary cell walls can be gained. The data shows that SAXS can serve as a valuable tool for the analysis of cellulose microfibril orientation in primary cell walls and, in consequence, add to the understanding of its mechanical behaviour and the intriguing mechanisms behind cell growth. PMID:25170343

  17. Antibody Production in Plants and Green Algae.

    PubMed

    Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

    2016-04-29

    Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae. PMID:26905655

  18. Antibody Production in Plants and Green Algae.

    PubMed

    Yusibov, Vidadi; Kushnir, Natasha; Streatfield, Stephen J

    2016-04-29

    Monoclonal antibodies (mAbs) have a wide range of modern applications, including research, diagnostic, therapeutic, and industrial uses. Market demand for mAbs is high and continues to grow. Although mammalian systems, which currently dominate the biomanufacturing industry, produce effective and safe recombinant mAbs, they have a limited manufacturing capacity and high costs. Bacteria, yeast, and insect cell systems are highly scalable and cost effective but vary in their ability to produce appropriate posttranslationally modified mAbs. Plants and green algae are emerging as promising production platforms because of their time and cost efficiencies, scalability, lack of mammalian pathogens, and eukaryotic posttranslational protein modification machinery. So far, plant- and algae-derived mAbs have been produced predominantly as candidate therapeutics for infectious diseases and cancer. These candidates have been extensively evaluated in animal models, and some have shown efficacy in clinical trials. Here, we review ongoing efforts to advance the production of mAbs in plants and algae.

  19. New records of marine algae in Vietnam

    NASA Astrophysics Data System (ADS)

    Le Hau, Nhu; Ly, Bui Minh; Van Huynh, Tran; Trung, Vo Thanh

    2015-06-01

    In May, 2013, a scientific expedition was organized by the Vietnam Academy of Science and Technology (VAST) and the Far Eastern Branch of the Russian Academy of Sciences (FEBRAS) through the frame of the VAST-FEBRAS International Collaboration Program. The expedition went along the coast of Vietnam from Quang Ninh to Kien Giang. The objective was to collect natural resources to investigate the biological and biochemical diversity of the territorial waters of Vietnam. Among the collected algae, six taxa are new records for the Vietnam algal flora. They are the red algae Titanophora pikeana (Dickie) Feldmann from Cu Lao Xanh Island, Laurencia natalensis Kylin from Tho Chu Island, Coelothrix irregularis (Harvey) Børgesen from Con Dao Island, the green algae Caulerpa oligophylla Montagne, Caulerpa andamanensis (W.R. Taylor) Draisma, Prudhomme et Sauvage from Phu Quy Island, and Caulerpa falcifolia Harvey & Bailey from Ly Son Island. The seaweed flora of Vietnam now counts 833 marine algal taxa, including 415 Rhodophyta, 147 Phaeophyceae, 183 Chlorophyta, and 88 Cyanobacteria.

  20. Environmental life cycle comparison of algae to other bioenergy feedstocks.

    PubMed

    Clarens, Andres F; Resurreccion, Eleazer P; White, Mark A; Colosi, Lisa M

    2010-03-01

    Algae are an attractive source of biomass energy since they do not compete with food crops and have higher energy yields per area than terrestrial crops. In spite of these advantages, algae cultivation has not yet been compared with conventional crops from a life cycle perspective. In this work, the impacts associated with algae production were determined using a stochastic life cycle model and compared with switchgrass, canola, and corn farming. The results indicate that these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location. Only in total land use and eutrophication potential do algae perform favorably. The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO(2) and fertilizer. To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae. To demonstrate the benefits of algae production coupled with wastewater treatment, the model was expanded to include three different municipal wastewater effluents as sources of nitrogen and phosphorus. Each provided a significant reduction in the burdens of algae cultivation, and the use of source-separated urine was found to make algae more environmentally beneficial than the terrestrial crops. PMID:20085253

  1. Electro-coagulation-flotation process for algae removal.

    PubMed

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view. PMID:20042280

  2. Electro-coagulation-flotation process for algae removal.

    PubMed

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

  3. Transient removal of alkaline zones after excitation of Chara cells is associated with inactivation of high conductance in the plasmalemma.

    PubMed

    Bulychev, Alexander A; Krupenina, Natalia A

    2009-08-01

    The action potential (AP) of excitable plant cells is a multifunctional physiological signal. Its generation in characean algae suppresses the pH banding for 15-30 min and enhances the heterogeneity of spatial distribution of photosynthetic activity. This suppression is largely due to the cessation of H(+) influx (OH(-) efflux) in the alkaline cell regions. Measurements of local pH and membrane conductance in individual space-clamped alkaline zones (small cell areas bathed in an isolated pool of external medium) showed that the AP generation is followed by the transient disappearance of alkaline zone in parallel with a large decrease in membrane conductance. These changes, specific to alkaline zones, were only observed under continuous illumination following a relaxation period of at least 15 min after previous excitation. The excitation of dark-adapted cells produced no conductance changes in the post-excitation period. The results indicate that the origin of alkaline zones in characean cells is not due to operation of electroneutral H(+)/HCO(3)(-) symport or OH(-)/HCO(3)(-) antiport. It is concluded that the membrane excitation is associated with inactivation of plasmalemma high conductance in the alkaline cell regions. PMID:19820298

  4. Transient removal of alkaline zones after excitation of Chara cells is associated with inactivation of high conductance in the plasmalemma.

    PubMed

    Bulychev, Alexander A; Krupenina, Natalia A

    2009-08-01

    The action potential (AP) of excitable plant cells is a multifunctional physiological signal. Its generation in characean algae suppresses the pH banding for 15-30 min and enhances the heterogeneity of spatial distribution of photosynthetic activity. This suppression is largely due to the cessation of H(+) influx (OH(-) efflux) in the alkaline cell regions. Measurements of local pH and membrane conductance in individual space-clamped alkaline zones (small cell areas bathed in an isolated pool of external medium) showed that the AP generation is followed by the transient disappearance of alkaline zone in parallel with a large decrease in membrane conductance. These changes, specific to alkaline zones, were only observed under continuous illumination following a relaxation period of at least 15 min after previous excitation. The excitation of dark-adapted cells produced no conductance changes in the post-excitation period. The results indicate that the origin of alkaline zones in characean cells is not due to operation of electroneutral H(+)/HCO(3)(-) symport or OH(-)/HCO(3)(-) antiport. It is concluded that the membrane excitation is associated with inactivation of plasmalemma high conductance in the alkaline cell regions.

  5. Hydrogenases in green algae: do they save the algae's life and solve our energy problems?

    PubMed

    Happe, Thomas; Hemschemeier, Anja; Winkler, Martin; Kaminski, Annette

    2002-06-01

    Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool. They are transferred to the hydrogenase by photosystem I and ferredoxin. Thus, the [Fe]-hydrogenase is an electron 'valve' that enables the algae to survive under anaerobic conditions. During sulfur deprivation, illuminated algal cultures evolve large quantities of hydrogen gas, and this promises to be an alternative future energy source. PMID:12049920

  6. Microplate Technique for Determining Accumulation of Metals by Algae

    PubMed Central

    Hassett, James M.; Jennett, J. Charles; Smith, James E.

    1981-01-01

    A microplate technique was developed to determine the conditions under which pure cultures of algae removed heavy metals from aqueous solutions. Variables investigated included algal species and strain, culture age (11 and 44 days), metal (mercury, lead, cadmium, and zinc), pH, effects of different buffer solutions, and time of exposure. Plastic, U-bottomed microtiter plates were used in conjunction with heavy metal radionuclides to determine concentration factors for metal-alga combinations. The technique developed was rapid, statistically reliable, and economical of materials and cells. Results (expressed as concentration factors) were in reasonably good agreement with literature values. All species of algae studied removed mercury from solution. Green algae proved better at accumulating cadmium than did blue-green algae. No alga studied removed zinc, perhaps because cells were maintained in the dark during the labeling period. Chlamydomonas sp. proved superior in ability to remove lead from solution. PMID:16345764

  7. Exploring the potential of algae/bacteria interactions.

    PubMed

    Kouzuma, Atsushi; Watanabe, Kazuya

    2015-06-01

    Algae are primary producers in aquatic ecosystems, where heterotrophic bacteria grow on organics produced by algae and recycle nutrients. Ecological studies have identified the co-occurrence of particular species of algae and bacteria, suggesting the presence of their specific interactions. Algae/bacteria interactions are categorized into nutrient exchange, signal transduction and gene transfer. Studies have examined how these interactions shape aquatic communities and influence geochemical cycles in the natural environment. In parallel, efforts have been made to exploit algae for biotechnology processes, such as water treatment and bioenergy production, where bacteria influence algal activities in various ways. We suggest that better understanding of mechanisms underlying algae/bacteria interactions will facilitate the development of more efficient and/or as-yet-unexploited biotechnology processes.

  8. Method and apparatus for iterative lysis and extraction of algae

    SciTech Connect

    Chew, Geoffrey; Boggs, Tabitha; Dykes, Jr., H. Waite H.; Doherty, Stephen J.

    2015-12-01

    A method and system for processing algae involves the use of an ionic liquid-containing clarified cell lysate to lyse algae cells. The resulting crude cell lysate may be clarified and subsequently used to lyse algae cells. The process may be repeated a number of times before a clarified lysate is separated into lipid and aqueous phases for further processing and/or purification of desired products.

  9. Bromophenols from marine algae with potential anti-diabetic activities

    NASA Astrophysics Data System (ADS)

    Lin, Xiukun; Liu, Ming

    2012-12-01

    Marine algae contain various bromophenols with a variety of biological activities, including antimicrobial, anticancer, and anti-diabetic effects. Here, we briefly review the recent progress in researches on the biomaterials from marine algae, emphasizing the relationship between the structure and the potential anti-diabetic applications. Bromophenols from marine algae display their hyperglycemic effects by inhibiting the activities of protein tyrosine phosphatase 1B, α-glucosidase, as well as other mechanisms.

  10. Algae to Bio-Crude in Less Than 60 Minutes

    ScienceCinema

    Elliott, Doug

    2016-07-12

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  11. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, Elias

    1984-01-01

    Efficiency of process for producing H.sub.2 by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  12. Algae to Bio-Crude in Less Than 60 Minutes

    SciTech Connect

    Elliott, Doug

    2013-12-17

    Engineers have created a chemical process that produces useful crude oil just minutes after engineers pour in harvested algae -- a verdant green paste with the consistency of pea soup. The PNNL team combined several chemical steps into one continuous process that starts with an algae slurry that contains as much as 80 to 90 percent water. Most current processes require the algae to be dried -- an expensive process that takes a lot of energy. The research has been licensed by Genifuel Corp.

  13. Method for producing hydrogen and oxygen by use of algae

    DOEpatents

    Greenbaum, E.

    1982-06-16

    Efficiency of process for producing H/sub 2/ by subjecting algae in an aqueous phase to light irradiation is increased by culturing algae which has been bleached during a first period of irradiation in a culture medium in an aerobic atmosphere until it has regained color and then subjecting this algae to a second period of irradiation wherein hydrogen is produced at an enhanced rate.

  14. Overall Energy Considerations for Algae Species Comparison and Selection in Algae-to-Fuels Processes

    SciTech Connect

    Link, D.; Kail, B.; Curtis, W.; Tuerk,A.

    2011-01-01

    The controlled growth of microalgae as a feedstock for alternative transportation fuel continues to receive much attention. Microalgae have the characteristics of rapid growth rate, high oil (lipid) content, and ability to be grown in unconventional scenarios. Algae have also been touted as beneficial for CO{sub 2} reuse, as algae can be grown using CO{sub 2} emissions from fossil-based energy generation. Moreover, algae does not compete in the food chain, lessening the 'food versus fuel' debate. Most often, it is assumed that either rapid production rate or high oii content should be the primary factor in algae selection for algae-to-fuels production systems. However, many important characteristics of algae growth and lipid production must be considered for species selection, growth condition, and scale-up. Under light limited, high density, photoautotrophic conditions, the inherent growth rate of an organism does not affect biomass productivity, carbon fixation rate, and energy fixation rate. However, the oil productivity is organism dependent, due to physiological differences in how the organisms allocate captured photons for growth and oil production and due to the differing conditions under which organisms accumulate oils. Therefore, many different factors must be considered when assessing the overall energy efficiency of fuel production for a given algae species. Two species, Chlorella vulgaris and Botryococcus braunii, are popular choices when discussing algae-to-fuels systems. Chlorella is a very robust species, often outcompeting other species in mixed-culture systems, and produces a lipid that is composed primarily of free fatty acids and glycerides. Botryococcus is regarded as a slower growing species, and the lipid that it produces is characterized by high hydrocarbon content, primarily C28-C34 botryococcenes. The difference in growth rates is often considered to be an advantage oiChlorella. However, the total energy captured by each algal species in

  15. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  16. Method and apparatus for lysing and processing algae

    DOEpatents

    Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite H.; Di Salvo, Roberto

    2013-03-05

    Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells at lower temperatures than existing algae processing methods. A salt or salt solution is used as a separation agent and to remove water from the ionic liquid, allowing the ionic liquid to be reused. The used salt may be dried or concentrated and reused. The relatively low lysis temperatures and recycling of the ionic liquid and salt reduce the environmental impact of the algae processing while providing biofuels and other useful products.

  17. Exploring the potential of using algae in cosmetics.

    PubMed

    Wang, Hui-Min David; Chen, Ching-Chun; Huynh, Pauline; Chang, Jo-Shu

    2015-05-01

    The applications of microalgae in cosmetic products have recently received more attention in the treatment of skin problems, such as aging, tanning and pigment disorders. There are also potential uses in the areas of anti-aging, skin-whitening, and pigmentation reduction products. While algae species have already been used in some cosmetic formulations, such as moisturizing and thickening agents, algae remain largely untapped as an asset in this industry due to an apparent lack of utility as a primary active ingredient. This review article focuses on integrating studies on algae pertinent to skin health and beauty, with the purpose of identifying serviceable algae functions in practical cosmetic uses.

  18. TAXONOMIC REEXAMINATION OF CHARA GLOBULARIS (CHARALES, CHAROPHYCEAE) FROM JAPAN BASED ON OOSPORE MORPHOLOGY AND rbcL GENE SEQUENCES, AND THE DESCRIPTION OF C. LEPTOSPORA SP. NOV.(1).

    PubMed

    Sakayama, Hidetoshi; Kasai, Fumie; Nozaki, Hisayoshi; Watanabe, Makoto M; Kawachi, Masanobu; Shigyo, Mikao; Nishihiro, Jun; Washitani, Izumi; Krienitz, Lothar; Ito, And Motomi

    2009-08-01

    Chara globularis Thuillier (=f. globularis sensu R. D. Wood) is a widespread species of the genus and inhabits fresh- and brackish-water environments. In an attempt to reexamine the taxonomic status of C. globularis collected from Japan, we reassessed vegetative and oospore morphology of Japanese material and herbarium specimens originating from Europe (including the type specimen) and conducted molecular phylogenetic analyses based on rbcL gene sequences. Although the other vegetative morphologies were consistent with the description of C. globularis f. globularis sensu R. D. Wood, we identified two types of branchlets within the Japanese materials: one has elongate end segments (EL type), and the other has short end segments (SH type) corresponding to the type material. Moreover, the oospore wall of the EL type was different from that in the SH type. The oospores of the EL type were dark brown to reddish brown and had a spongy pattern with the pusticular elevations on the fossa wall, whereas the fossa wall of the SH type was black with a granulate to papillate or fine pusticular pattern. In addition, our sequence data demonstrated that these two types are separated phylogenetically from each other. Therefore, we describe the EL type as a new species, C. leptospora sp. nov.

  19. A technical evaluation of biodiesel from vegetable oils vs. algae. Will algae-derived biodiesel perform?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel, one of the most prominent renewable alternative fuels, can be derived from a variety of sources including vegetable oils, animal fats and used cooking oils as well as alternative sources such as algae. While issues such as land-use change, food vs. fuel, feedstock availability, and produc...

  20. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them. PMID:27386675

  1. Factors affecting spore germination in algae - review.

    PubMed

    Agrawal, S C

    2009-01-01

    This review surveys whatever little is known on the influence of different environmental factors like light, temperature, nutrients, chemicals (such as plant hormones, vitamins, etc.), pH of the medium, biotic factors (such as algal extracellular substances, algal concentration, bacterial extracellular products, animal grazing and animal extracellular products), water movement, water stress, antibiotics, UV light, X-rays, gamma-rays, and pollution on the spore germination in algae. The work done on the dormancy of algal spores and on the role of vegetative cells in tolerating environmental stress is also incorporated. PMID:19826917

  2. [THE MICROSCOPIC ALGAE AS HUMAN PATHOGENS].

    PubMed

    Roman, Manuel Casal

    2014-01-01

    Some microscopic algae can cause different infectious diseases in humans, including skin, bone, and disseminated. These little-known emerging disease are more severe in immunocompromised patients. The confirmatory microbiological diagnosis must be done differential with yeast-like fungi that can be confused. Anti-fungal drugs and surgery, being quite frequent treatment failure have been used in the treatment. Given the increase of immunosuppression in the current medicine and new possibilities of microbiological diagnostics, it is logical that these diseases tend to increase, by which all physician should know them.

  3. Effect of petroleum hydrocarbons on algae

    SciTech Connect

    Bhadauria, S. ); Sengar, R.M.S. ); Mittal, S.; Bhattacharjee, S. )

    1992-01-01

    Algal species (65) were isolated from oil refinery effluent. Twenty-five of these species were cultured in Benecke's medium in a growth chamber, along with controls. Retardation in algal growth, inhibition in algal photosynthesis, and discoloration was observed in petroleum enriched medium. Few forms, viz. Cyclotella sp., Cosmarium sp., and Merismopedia sp. could not survive. The lag phase lengthened by several days and slope of exponential phase was also depressed. Chlamydomonas sp., Scenedesmus sp., Ankistrodesmus sp., Nitzschia sp. and Navicula sp. were comparatively susceptible to petroleum. Depression in carbon fixation, cell numbers, and total dry algal mass was noticeable, showing toxicity to both diatoms and green algae.

  4. Pheromones in marine algae: A technical approach

    NASA Astrophysics Data System (ADS)

    Gassmann, G.; Müller, D. G.; Fritz, P.

    1995-03-01

    It is now well known that many marine organisms use low-molecular volatile substances as signals, in order to coordinate activities between different individuals. The study of such pheromones requires the isolation and enrichment of the secretions from undisturbed living cells or organisms over extended periods of time. The Grob-Hersch extraction device, which we describe here, avoids adverse factors for the biological materials such as strong water currents, rising gas bubbles or chemical solvents. Furthermore, the formation of sea-water spray is greatly reduced. The application of this technique for the isolation of pheromones of marine algae and animals is described.

  5. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity.

  6. Viruses and viruslike particles of eukaryotic algae.

    PubMed Central

    Van Etten, J L; Lane, L C; Meints, R H

    1991-01-01

    Until recently there was little interest or information on viruses and viruslike particles of eukaryotic algae. However, this situation is changing. In the past decade many large double-stranded DNA-containing viruses that infect two culturable, unicellular, eukaryotic green algae have been discovered. These viruses can be produced in large quantities, assayed by plaque formation, and analyzed by standard bacteriophage techniques. The viruses are structurally similar to animal iridoviruses, their genomes are similar to but larger (greater than 300 kbp) than that of poxviruses, and their infection process resembles that of bacteriophages. Some of the viruses have DNAs with low levels of methylated bases, whereas others have DNAs with high concentrations of 5-methylcytosine and N6-methyladenine. Virus-encoded DNA methyltransferases are associated with the methylation and are accompanied by virus-encoded DNA site-specific (restriction) endonucleases. Some of these enzymes have sequence specificities identical to those of known bacterial enzymes, and others have previously unrecognized specificities. A separate rod-shaped RNA-containing algal virus has structural and nucleotide sequence affinities to higher plant viruses. Quite recently, viruses have been associated with rapid changes in marine algal populations. In the next decade we envision the discovery of new algal viruses, clarification of their role in various ecosystems, discovery of commercially useful genes in these viruses, and exploitation of algal virus genetic elements in plant and algal biotechnology. Images PMID:1779928

  7. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppm (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppm NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppm NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx 4.2 was not appreciably affected by 15.0 ppm of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  8. Effects of nitrogen dioxide on algae

    SciTech Connect

    Wodzinski, R.S.; Alexander, M.

    1980-01-01

    Photosynthetic activity of Anabaena flos-aquae in a soil suspension at an initial pH of 4.9 was almost totally eliminated after 3 days of exposure to 5.0 ppM (..mu..l/liter) NO/sub 2/, at which time the pH had fallen to 3.9. In contrast, A. flos-aquae in soil suspensions at an initial pH of 6.0 was not inhibited after 3 days by 5.0 ppM NO/sub 2/, but the activity was reduced by half in the presence of 15.0 ppM NO/sub 2/; the pH was 6.5 and 5.8, respectively, in the NO/sub 2/-treated samples on day 3. Photosynthesis by the green algae Chlamydomonas reinhardtii and Ankistrodesmus falcatus in soil suspensions at an initial pH of approx. 4.2 was not appreciably affected by 15.0 ppM of NO/sub 2/ after 3 days, at which time the pH had fallen below 4.0. The high levels of NO/sub 2/ and low pH values required for toxicity suggest that blue-green and green algae probably will not be affected directly by NO/sub 2/ in polluted air.

  9. Algae-based oral recombinant vaccines.

    PubMed

    Specht, Elizabeth A; Mayfield, Stephen P

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for "molecular pharming" in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered - from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

  10. Respiratory Chain of Colorless Algae II. Cyanophyta

    PubMed Central

    Webster, D. A.; Hackett, D. P.

    1966-01-01

    Whole cell difference spectra of the blue-green algae, Saprospira grandis, Leucothrix mucor, and Vitreoscilla sp. have one, or at the most 2, broad α-bands near 560 mμ. At −190° these bands split to give 4 peaks in the α-region for b and c-type cytochromes, but no α-band for a-type cytochromes is visible. The NADH oxidase activity of these organisms was shown to be associated with particulate fractions of cell homogenates. The response of this activity to inhibitors differed from the responses of the NADH oxidase activities of particulate preparations from the green algae and higher plants to the same inhibitors, but is more typical of certain bacteria. No cytochrome oxidase activity was present in these preparations. The respiration of Saprospira and Vitreoscilla can be light-reversibly inhibited by CO, and all 3 organisms have a CO-binding pigment whose CO complex absorbs near 570, 535, and 417 mμ. The action spectrum for the light reversal of CO-inhibited Vitreoscilla respiration shows maxima at 568, 534, and 416 mμ. The results suggest that the terminal oxidase in these blue-greens is an o-type cytochrome. Images PMID:5932404

  11. Algae Biofuels Co-Location Assessment Tool

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with themore » requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.« less

  12. Algae Biofuels Co-Location Assessment Tool

    SciTech Connect

    2013-09-18

    ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with the requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.

  13. Shewanella algae Peritonitis in Patients on Peritoneal Dialysis.

    PubMed

    Shanmuganathan, Malini; Goh, Bak Leong; Lim, Christopher; NorFadhlina, Zakaria; Fairol, Ibrahim

    Patients with peritonitis present with abdominal pain, diarrhea, fever, and turbid peritoneal dialysis (PD) fluid. Shewanella algae peritonitis has not yet been reported in PD patients in the literature. We present the first 2 cases of Shewanella algae peritonitis in PD patients. Mupirocin cream is applied on the exit site as prophylactic antibiotic therapy. PMID:27659933

  14. [Marine algae of Baja California Sur, Mexico: nutritional value].

    PubMed

    Carrillo Domínguez, Silvia; Casas Valdez, Margarita; Ramos Ramos, Felipe; Pérez-Gil, Fernando; Sánchez Rodríguez, Ignacio

    2002-12-01

    The Baja California Peninsula is one of the richest regions of seaweed resources in México. The objective of this study was to determine the chemical composition of some marine algae species of Baja California Sur, with an economical potential due to their abundance and distribution, and to promote their use as food for human consumption and animal feeding. The algae studied were Green (Ulva spp., Enteromorpha intestinalis, Caulerpa sertularoides, Bryopsis hypnoides), Red (Laurencia johnstonii, Spyridia filamentosa, Hypnea valentiae) and Brown (Sargassum herporizum, S. sinicola, Padina durvillaei, Hydroclathrus clathrathus, Colpomenia sinuosa). The algae were dried and ground before analysis. In general, the results showed that algae had a protein level less than 11%, except L. johnstonii with 18% and low energy content. The ether extract content was lower than 1%. However, the algae were a good source of carbohydrates and inorganic matter.

  15. Cryoalgotox: Use of cryopreserved alga in a semistatic microplate test

    SciTech Connect

    Benhra, A.; Radetski, C.M.; Ferard, J.F.

    1997-03-01

    Use of cryopreserved alga Selenastrum capricornutum has been evaluated as a simple and cost-efficient procedure in a new semistatic algal ecotoxicity test. Experiments have been conducted to compare performance criteria of this method, named Cryoalgotox, versus the classic microplate test using fresh algae. Cryoalgotox 72-h 50% effective concentrations (EC50s) determined with Cd{sup 2+}, Cu{sup 2+}, Cr{sup 6+}, and atrazine were more sensitive, repeatable (low coefficients of variation), and reproducible (low time effect) than the results obtained with the classical microplate tests. The effect of storage time at {minus}80 C on the sensitivity of the algae was assessed using cadmium as a toxic reference; it was shown that algae stored at {minus}80 C over a 3-month period gave comparable toxicity results to those found with fresh algae.

  16. Algae Farming in Low Earth Orbit: Past Present and Future

    NASA Astrophysics Data System (ADS)

    Morrison, N.

    Algal strains used as a production engine represent a novel example of living mechanical systems with tremendous potential for applications in space. Algae use photosynthesis to create lipids, glycerin, and biomass, with different strains of algae producing different oils. Algae can be grown to produce many types of oils, with low, medium or long hydrocarbon chain lengths. This article examines the history of algae research, as well as its value to astronauts as both a food supplement and as an oxygen production and carbon sequester engine. Consideration is given to ways algae is currently being used and tested in space, followed by a look forward envisioning dynamic living technological systems that can help to sustain our race as we travel the void between stars.

  17. Mitigating ammonia nitrogen deficiency in dairy wastewaters for algae cultivation.

    PubMed

    Lu, Qian; Zhou, Wenguang; Min, Min; Ma, Xiaochen; Ma, Yiwei; Chen, Paul; Zheng, Hongli; Doan, Yen T T; Liu, Hui; Chen, Chi; Urriola, Pedro E; Shurson, Gerald C; Ruan, Roger

    2016-02-01

    This study demonstrated that the limiting factor to algae growth on dairy wastewater was the ammonia nitrogen deficiency. Dairy wastewaters were mixed with a slaughterhouse wastewater that has much higher ammonia nitrogen content. The results showed the mixing wastewaters improved the nutrient profiles and biomass yield at low cost. Algae grown on mixed wastewaters contained high protein (55.98-66.91%) and oil content (19.10-20.81%) and can be exploited to produce animal feed and biofuel. Furthermore, algae grown on mixed wastewater significantly reduced nutrient contents remained in the wastewater after treatment. By mitigating limiting factor to algae growth on dairy wastewaters, the key issue of low biomass yield of algae grown on dairy wastewaters was resolved and the wastewater nutrient removal efficiency was significantly improved by this study.

  18. The mechanism of boron mobility in wheat and canola phloem.

    PubMed

    Stangoulis, James; Tate, Max; Graham, Robin; Bucknall, Martin; Palmer, Lachlan; Boughton, Berin; Reid, Robert

    2010-06-01

    Low-molecular-weight borate complexes were isolated from canola (Brassica napus) and wheat (Triticum aestivum) phloem exudates, as well as the cytoplasm of the fresh-water alga Chara corallina, and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Phloem exudate was collected from field-grown canola inflorescence stalks by shallow incision, while wheat phloem exudate was collected by aphid stylectomy. Chara cytoplasm was collected by careful manual separation of the cell wall, vacuole, and cytosolic compartments. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry showed the presence of isotopic borate complexes, at mass-to-charge ratio of 690.22/691.22 in the canola and wheat phloem and at 300.11/301.11 in canola phloem and Chara cytoplasm. Using reference compounds, the borate complexes with mass-to-charge ratio 690.22/691.22 was identified as a bis-sucrose (Suc) borate complex in which the 4,6-hydroxyl pairs from the two alpha-glucopyranoside moieties formed an [L(2)B](-1) complex. Further investigation using liquid chromatography electrospray ionization triple quadrupole mass spectrometry analysis confirmed the presence of the bis-Suc borate complex in wheat phloem with a concentration up to 220 microm. The 300.11/301.11 complex was putatively identified as a bis-N-acetyl-serine borate complex but its concentration was below the detection limits of the liquid chromatography electrospray ionization triple quadrupole mass spectrometer so could not be quantified. The presence of borate complexes in the phloem provides a mechanistic explanation for the observed phloem boron mobility in canola and wheat and other species that transport Suc as their primary photoassimilate.

  19. The Mechanism of Boron Mobility in Wheat and Canola Phloem1[C][OA

    PubMed Central

    Stangoulis, James; Tate, Max; Graham, Robin; Bucknall, Martin; Palmer, Lachlan; Boughton, Berin; Reid, Robert

    2010-01-01

    Low-molecular-weight borate complexes were isolated from canola (Brassica napus) and wheat (Triticum aestivum) phloem exudates, as well as the cytoplasm of the fresh-water alga Chara corallina, and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Phloem exudate was collected from field-grown canola inflorescence stalks by shallow incision, while wheat phloem exudate was collected by aphid stylectomy. Chara cytoplasm was collected by careful manual separation of the cell wall, vacuole, and cytosolic compartments. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry showed the presence of isotopic borate complexes, at mass-to-charge ratio of 690.22/691.22 in the canola and wheat phloem and at 300.11/301.11 in canola phloem and Chara cytoplasm. Using reference compounds, the borate complexes with mass-to-charge ratio 690.22/691.22 was identified as a bis-sucrose (Suc) borate complex in which the 4,6-hydroxyl pairs from the two α-glucopyranoside moieties formed an [L2B]−1 complex. Further investigation using liquid chromatography electrospray ionization triple quadrupole mass spectrometry analysis confirmed the presence of the bis-Suc borate complex in wheat phloem with a concentration up to 220 μm. The 300.11/301.11 complex was putatively identified as a bis-N-acetyl-serine borate complex but its concentration was below the detection limits of the liquid chromatography electrospray ionization triple quadrupole mass spectrometer so could not be quantified. The presence of borate complexes in the phloem provides a mechanistic explanation for the observed phloem boron mobility in canola and wheat and other species that transport Suc as their primary photoassimilate. PMID:20413647

  20. The mitigating effect of calcification-dependent of utilization of inorganic carbon of Chara vulgaris Linn on NH4-N toxicity.

    PubMed

    Wang, Heyun; Ni, Leyi; Xie, Ping

    2013-09-01

    Increased ammonium (NH4-N) concentrations in water bodies have been reported to adversely affect the dominant species of submersed vegetation in meso-eutrophic waters worldwide. However calcareous plants were lowly sensitive to NH4-N toxicity. In order to make clear the function of calcification in the tolerance of calcareous plants to NH4-N stress, we studied the effects of increased HCO3(-) and additional NH4-N on calcification and utilization of dissolve inorganic carbon (DIC) in Chara vulgaris Linn in a 7-d sub-acute experiment (light:dark 12:12h) carried out in an open experimental system in lab. Results revealed that calcification was dependent of utilization of dissolve inorganic carbon. Additional HCO3(-) significantly decreased the increase of pH while additional NH4-N did not. And additional HCO3(-) significantly improved calcification while NH4-N did in versus in relation to the variation of DIC concentration. However, addition of both HCO3(-) and NH4-N increased utilization of DIC. This resulted in calcification to utilization of DIC ratio decreased under additional NH4-N condition while increased under additional HCO3(-) conditions in response to the variation of solution pH. In the present study, external HCO3(-) decreased the increase of solution pH by increasing calcification, which correspondingly mitigated the toxic effect of high NH4-N. And we argue that the mitigating effect of increased HCO3(-) on NH4-N toxicity is dependent of plant calcification, and it is a positive feedback mechanism, potentially leading to the dominance of calcareous plants in meso-eutrophic water bodies.

  1. Transfer of PCBs via lactation simultaneously induces the expression of P450 isoenzymes and the protooncogenes c-Ha-ras and c-raf in neonates.

    PubMed

    Borlak, J T; Scott, A; Henderson, C J; Jenke, H J; Wolf, C R

    1996-02-23

    At the first day of lactation, maternal rats were injected with a single i.p. dose of 100 or 250 mg/kg body weight of a mixture of polychlorinated biphenyls (Aroclor 1254). This treatment caused significant increases in both material and neonatal hepatic cytochrome P-450, cytochrome b5, and cytochrome-c-(P-450) reductase. Transfer of PCBs via lactation resulted in significant increases in hepatic enzyme activities catalysed by neonatal CYP1A1, CYP1A2, CYP2B1, CYP3A1, and CYP2E1 using a variety of substrates. In contrast, the metabolism of dimethylnitrosamine and aminopyrine was only marginally (up to 2-fold) increased in maternal animals four days post treatment. Further measurements showed significant increases in maternal and neonatal epoxide hydrolase, glutathione-S-transferase, and UDP-glucuronyl transferase activities, thus suggesting a coordinated response for an induction of CYP1A1, CYP1A2, CYP2A1, CYP2B1, CYP2E1, CYP3A1, and CYP4A1 in both maternal and neonatal CYP2C6, and at the higher dose the expression of neonatal CYP2E1 was significantly reduced. Northern blot analysis provided further evidence for significant increases in maternal and neonatal hepatic CYP1A1, CYP1A2, CYP2B1, and CYP2E1 mRNA, but reduced amounts of CYP2C7 and CYP4A1 mRNA. Additional Northern blot hybridization experiments may suggest an increased expression of the protooncogenes c-Ha-ras and c-raf in the mother and the neonate upon treatment of maternal rats with Aroclor 1254. Lactation itself may result in an increased expression of the latter protooncogenes, but the mRNA of the protooncogenes c-erb A and c-erb B was not detected in any of the tissues examined.

  2. The mitigating effect of calcification-dependent of utilization of inorganic carbon of Chara vulgaris Linn on NH4-N toxicity.

    PubMed

    Wang, Heyun; Ni, Leyi; Xie, Ping

    2013-09-01

    Increased ammonium (NH4-N) concentrations in water bodies have been reported to adversely affect the dominant species of submersed vegetation in meso-eutrophic waters worldwide. However calcareous plants were lowly sensitive to NH4-N toxicity. In order to make clear the function of calcification in the tolerance of calcareous plants to NH4-N stress, we studied the effects of increased HCO3(-) and additional NH4-N on calcification and utilization of dissolve inorganic carbon (DIC) in Chara vulgaris Linn in a 7-d sub-acute experiment (light:dark 12:12h) carried out in an open experimental system in lab. Results revealed that calcification was dependent of utilization of dissolve inorganic carbon. Additional HCO3(-) significantly decreased the increase of pH while additional NH4-N did not. And additional HCO3(-) significantly improved calcification while NH4-N did in versus in relation to the variation of DIC concentration. However, addition of both HCO3(-) and NH4-N increased utilization of DIC. This resulted in calcification to utilization of DIC ratio decreased under additional NH4-N condition while increased under additional HCO3(-) conditions in response to the variation of solution pH. In the present study, external HCO3(-) decreased the increase of solution pH by increasing calcification, which correspondingly mitigated the toxic effect of high NH4-N. And we argue that the mitigating effect of increased HCO3(-) on NH4-N toxicity is dependent of plant calcification, and it is a positive feedback mechanism, potentially leading to the dominance of calcareous plants in meso-eutrophic water bodies. PMID:23755986

  3. Further ultrastructural research of Chara vulgaris spermiogenesis: endoplasmic reticulum, structure of chromatin, 3H-lysine and 3H-arginine incorporation.

    PubMed

    Kwiatkowska, Maria; Popłońska, Katarzyna

    2002-01-01

    On the basis of morphological features, 10 consecutive structural phases of spermatids were identified in Chara vulgaris spermiogenesis. They were schematically presented. In early and middle spermiogenesis, i.e. during the period preceding formation of fibrillar structure of mature spermatozoid nucleus, a slight remodelling of chromatin, accompanied by proplastid transformation into an amyloplast as well as by development of 2 flagella and a microtubular manchette, is observed. First, condensed chromatin concentrates around the nuclear envelope (phases III-V) and then it transforms into a network-like structure (phase VI). This change in chromatin structure is preceded by nucleolar extrusion to the cytoplasm where nucleoli become degraded (phase IV) and by a dynamic development of rough endoplasmic reticulum (RER) (phase V) which is continuous with the nuclear envelope and with RER of the adjacent spermatids via plasmodesmata. The inner membrane of the nuclear envelope invaginates into the nucleoplasm in which "nuclear reticulum" appears. It all happens during increased 3H-arginine and 3H-lysine incorporation into proteins which are rapidly translocated into the nucleus. In medium-late spermiogenesis (phases VI-VIII), network-like condensed chromatin disappears. Next, the structure of the nucleus changes dramatically. Short, randomly positioned fibrils (phase VII) appear and gradually become longer (phase VIII), thicker (phase IX) and more distinct, lying parallel to the surface of elongating and curling nucleus. Membranes of the nuclear envelope become closer to each other and a distinct dark layer--probably lamin--appears adhering to the inner membrane of the nuclear envelope. Towards the end of spermiogenesis (phase X), very densely packed parallel helices, ca 2 nm in diameter, are visible. The surfaces of flagella and the spermatozoid are covered with diamond-shaped larger and smaller scales, respectively. Helically coiled spermatozoids are liberated from

  4. High-fidelity phototaxis in biflagellate algae

    NASA Astrophysics Data System (ADS)

    Leptos, Kyriacos; Chioccioli, Maurizio; Furlan, Silvano; Pesci, Adriana; Goldstein, Raymond

    2015-11-01

    The single-cell alga Chlamydomonas reinhardtii is a motile biflagellate that can swim towards light for its photosynthetic requirements, a behavior referred to as phototaxis. The cell responds upon light stimulation through its rudimentary eye - the eyespot - by changing the beating amplitude of its two flagella accordingly - a process called the photoresponse. All this occurs in a coordinated fashion as Chlamydomonas spins about its body axis while swimming, thus experiencing oscillating intensities of light. We use high-speed video microscopy to measure the flagellar dynamics of the photoresponse on immobilized cells and interpret the results with a mathematical model of adaptation similar to that used previously for Volvox. These results are incorporated into a model of phototactic steering to yield trajectories that are compared to those obtained by three-dimensional tracking. Implications of these results for the evolution of multicellularity in the Volvocales are discussed.

  5. Autophagy in the model alga Chlamydomonas reinhardtii.

    PubMed

    Pérez-Pérez, María Esther; Crespo, José L

    2010-05-01

    Degradation and recycling of intracellular components via autophagy is conserved among eukaryotes. This catabolic process is mediated by autophagy-related (ATG) proteins, which have been identified in different systems including yeasts, mammals and plants. The genome of the model alga Chlamydomonas reinhardtii contains homologues to yeast and plant ATG genes although autophagy has not been previously described in this organism. In our study, we report the molecular characterization of autophagy in Chlamydomonas. Using the ATG8 protein from Chlamydomonas as a molecular autophagy marker, we demonstrate that this degradative process is induced in stationary cells or under different stresses such as nutrient limitation, oxidative stress or the accumulation of misfolded proteins in the endoplasmic reticulum. Our results also indicate that TOR, a major regulator of autophagy, inhibits this process in Chlamydomonas.

  6. Swimming like algae: biomimetic soft artificial cilia

    PubMed Central

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond E.

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  7. Swimming like algae: biomimetic soft artificial cilia.

    PubMed

    Sareh, Sina; Rossiter, Jonathan; Conn, Andrew; Drescher, Knut; Goldstein, Raymond

    2013-01-01

    Cilia are used effectively in a wide variety of biological systems from fluid transport to thrust generation. Here, we present the design and implementation of artificial cilia, based on a biomimetic planar actuator using soft-smart materials. This actuator is modelled on the cilia movement of the alga Volvox, and represents the cilium as a piecewise constant-curvature robotic actuator that enables the subsequent direct translation of natural articulation into a multi-segment ionic polymer metal composite actuator. It is demonstrated how the combination of optimal segmentation pattern and biologically derived per-segment driving signals reproduce natural ciliary motion. The amenability of the artificial cilia to scaling is also demonstrated through the comparison of the Reynolds number achieved with that of natural cilia. PMID:23097503

  8. Random flow induced by swimming algae

    NASA Astrophysics Data System (ADS)

    Kantsler, Vasily; Rushkin, Ilia; Goldstein, Raymond

    2010-11-01

    In this work we studied the random flow induced in a fluid by the motion of a dilute suspension of the swimming algae Volvox carteri. The fluid velocity in the suspension is a superposition of the flow fields set up by the individual organisms, which in turn have multipole contributions that decay as inverse powers of distance from the organism. Here we show that the conditions under which the central limit theorem guarantees a Gaussian probability distribution function of velocity fluctuations are satisfied when the leading force singularity is a Stokeslet. Deviations from Gaussianity are shown to arise from near-field effects. Comparison is made with the statistical properties of abiotic sedimenting suspensions. The experimental results are supplemented by extensive numerical studies.

  9. Chloroplast Phylogenomic Inference of Green Algae Relationships

    PubMed Central

    Sun, Linhua; Fang, Ling; Zhang, Zhenhua; Chang, Xin; Penny, David; Zhong, Bojian

    2016-01-01

    The green algal phylum Chlorophyta has six diverse classes, but the phylogenetic relationship of the classes within Chlorophyta remains uncertain. In order to better understand the ancient Chlorophyta evolution, we have applied a site pattern sorting method to study compositional heterogeneity and the model fit in the green algal chloroplast genomic data. We show that the fastest-evolving sites are significantly correlated with among-site compositional heterogeneity, and these sites have a much poorer fit to the evolutionary model. Our phylogenomic analyses suggest that the class Chlorophyceae is a monophyletic group, and the classes Ulvophyceae, Trebouxiophyceae and Prasinophyceae are non-monophyletic groups. Our proposed phylogenetic tree of Chlorophyta will offer new insights to investigate ancient green algae evolution, and our analytical framework will provide a useful approach for evaluating and mitigating the potential errors of phylogenomic inferences. PMID:26846729

  10. An algae-covered alligator rests warily

    NASA Technical Reports Server (NTRS)

    2000-01-01

    An algae-covered alligator keeps a wary eye open as it rests in one of the ponds at Kennedy Space Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  11. Granular activated algae for wastewater treatment.

    PubMed

    Tiron, O; Bumbac, C; Patroescu, I V; Badescu, V R; Postolache, C

    2015-01-01

    The study used activated algae granules for low-strength wastewater treatment in sequential batch mode. Each treatment cycle was conducted within 24 h in a bioreactor exposed to 235 μmol/m²/s light intensity. Wastewater treatment was performed mostly in aerobic conditions, oxygen being provided by microalgae. High removal efficiency of chemical oxygen demand (COD) was achieved (86-98%) in the first hours of the reaction phase, during which the indicator's removal rate was 17.4 ± 3.9 mg O₂/g h; NH(4)(+) was removed during organic matter degradation processes with a rate of 1.8 ± 0.6 mg/g h. After almost complete COD removal, the (O⁺) remaining in the liquor was removed through nitrification processes promoted by the increase of the liquor's oxygen saturation (O₂%), the transformation rate of NH4(+) into NO(3)(-) increasing from 0.14 ± 0.05 to 1.5 ± 0.4 mg NH4(+)/g h, along with an O₂% increase. A wide removal efficiency was achieved in the case of PO(4)(3)(-) (11-85%), with the indicator's removal rate being 1.3 ± 0.7 mg/g h. In the provided optimum conditions, the occurrence of the denitrifying activity was also noticed. A large pH variation was registered (5-8.5) during treatment cycles. The granular activated algae system proved to be a promising alternative for wastewater treatment as it also sustains cost-efficient microalgae harvesting, with microalgae recovery efficiency ranging between 99.85 and 99.99% after granules settling with a velocity of 19 ± 3.6 m/h.

  12. The origin of red algae and the evolution of chloroplasts.

    PubMed

    Moreira, D; Le Guyader, H; Philippe, H

    2000-05-01

    Chloroplast structure and genome analyses support the hypothesis that three groups of organisms originated from the primary photosynthetic endosymbiosis between a cyanobacterium and a eukaryotic host: green plants (green algae + land plants), red algae and glaucophytes (for example, Cyanophora). Although phylogenies based on several mitochondrial genes support a specific green plants/red algae relationship, the phylogenetic analysis of nucleus-encoded genes yields inconclusive, sometimes contradictory results. To address this problem, we have analysed an alternative nuclear marker, elongation factor 2, and included new red algae and protist sequences. Here we provide significant support for a sisterhood of green plants and red algae. This sisterhood is also significantly supported by a multi-gene analysis of a fusion of 13 nuclear markers (5,171 amino acids). In addition, the analysis of an alternative fusion of 6 nuclear markers (1,938 amino acids) indicates that glaucophytes may be the closest relatives to the green plants/red algae group. Thus, our study provides evidence from nuclear markers for a single primary endosymbiosis at the origin of these groups, and supports a kingdom Plantae comprising green plants, red algae and glaucophytes.

  13. Isoprenoid biosynthesis in eukaryotic phototrophs: A spotlight on algae

    SciTech Connect

    Lohr M.; Schwender J.; Polle, J. E. W.

    2012-04-01

    Isoprenoids are one of the largest groups of natural compounds and have a variety of important functions in the primary metabolism of land plants and algae. In recent years, our understanding of the numerous facets of isoprenoid metabolism in land plants has been rapidly increasing, while knowledge on the metabolic network of isoprenoids in algae still lags behind. Here, current views on the biochemistry and genetics of the core isoprenoid metabolism in land plants and in the major algal phyla are compared and some of the most pressing open questions are highlighted. Based on the different evolutionary histories of the various groups of eukaryotic phototrophs, we discuss the distribution and regulation of the mevalonate (MVA) and the methylerythritol phosphate (MEP) pathways in land plants and algae and the potential consequences of the loss of the MVA pathway in groups such as the green algae. For the prenyltransferases, serving as gatekeepers to the various branches of terpenoid biosynthesis in land plants and algae, we explore the minimal inventory necessary for the formation of primary isoprenoids and present a preliminary analysis of their occurrence and phylogeny in algae with primary and secondary plastids. The review concludes with some perspectives on genetic engineering of the isoprenoid metabolism in algae.

  14. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P. PMID:26540532

  15. Biomass of algae growth on natural water medium.

    PubMed

    Ramaraj, Rameshprabu; Tsai, David Dah-Wei; Chen, Paris Honglay

    2015-01-01

    Algae are the dominant primary producers in aquatic ecosystems. Since algae are highly varied group organisms, which have important functions in ecosystem, and their biomass is an essential biological resource. Currently, algae have been applied increasingly to diverse range of biomass applications. Therefore, this study was aimed to investigate the ecological algae features of microalgal production by natural medium, ecological function by lab scale of the symbiotic reactor which is imitated nature ecosystem, and atmospheric CO2 absorption that was related the algal growth of biomass to understand algae in natural water body better. Consequently, this study took advantages of using the unsupplemented freshwater natural medium to produce microalgae. Algal biomass by direct measurement of total suspended solids (TSS) and volatile suspended solids (VSS) resulted as 0.14g/L and 0.08g/L respectively. The biomass measurements of TSS and VSS are the sensible biomass index for algae production. The laboratory results obtained in the present study proved the production of algae by the natural water medium is potentially feasible.

  16. Algae biomass cultivation in nitrogen rich biogas digestate.

    PubMed

    Krustok, I; Diaz, J G; Odlare, M; Nehrenheim, E

    2015-01-01

    Because microalgae are known for quick biomass growth and nutrient uptake, there has been much interest in their use in research on wastewater treatment methods. While many studies have concentrated on the algal treatment of wastewaters with low to medium ammonium concentrations, there are several liquid waste streams with high ammonium concentrations that microalgae could potentially treat. The aim of this paper was to test ammonium tolerance of the indigenous algae community of Lake Mälaren and to use this mixed consortia of algae to remove nutrients from biogas digestate. Algae from Lake Mälaren were cultivated in Jaworski's Medium containing a range of ammonium concentrations and the resulting algal growth was determined. The algae were able to grow at NH4-N concentrations of up to 200 mg L(-1) after which there was significant inhibition. To test the effectiveness of the lake water algae on the treatment of biogas digestate, different pre-cultivation set-ups and biogas digestate concentrations were tested. It was determined that mixing pre-cultivated suspension algae with 25% of biogas digestate by volume, resulting in an ammonium concentration of around 300 mg L(-1), produced the highest algal growth. The algae were effective in removing 72.8±2.2% of NH4-N and 41.4±41.4% of PO4-P.

  17. [Seasonal variation characteristics of algae biomass in Chaohu Lake].

    PubMed

    Jiang, Xia; Wang, Shu-Hang; Zhong, Li-Xiang; Jin, Xiang-Can; Sun, Shi-Qun

    2010-09-01

    The biomass and distribution of algae community in Chaohu Lake were investigated in 2008. At the same time, the seasonal variations of algae translocation between the sediment and overlying water were also quantitative studied by self-made "algae up/down trap". Chaohu Lake was dominated by Cyanobacteria all the year, and dominant Cyanobacteria species changed in different seasons. In spring, Anabaena was the dominant species, and Microcystis was the subdominant species; In the whole summer and autumn, the dominant species is Microcystis. Algae biomass increased significantly from May and the maximum appeared in August, was 146.37 mg x m(-3) with Chl-a. The value of algae biomass were 9.75-16.24 mg x kg(-1) in the surface sediments, and the minimum appeared in Summer, then the algae biomass increased gradually with the maximum value in winter. Translocation process between the sediment and the overlying water occurred throughout the study period. The recruitment rates increased at first with the maximum rates in early August, was 0.036 8 mg x (m2 x d) (-1), and then had a downward tendency. However the sedimentation rates increased slowly firstly with the maximum rate in early September, then it decreased sharply, was 0.032 1 mg x (m2 x d)(-1). Multiple stepwise regression showed that temperature was the most significant factor for the algae biomass in Chaohu Lake, Total nitrogen (TN) and Total phosphorus(TP) are sub-important factors.

  18. Photophysiology and cellular composition of sea ice algae

    SciTech Connect

    Lizotte, M.P.

    1989-01-01

    The productivity of sea ice algae depends on their physiological capabilities and the environmental conditions within various microhabitats. Pack ice is the dominant form of sea ice, but the photosynthetic activity of associated algae has rarely been studied. Biomass and photosynthetic rates of ice algae of the Weddell-Scotia Sea were investigated during autumn and winter, the period when ice cover grows from its minimum to maximum. Biomass-specific photosynthetic rates typically ranged from 0.3 to 3.0 {mu}g C {center dot} {mu}g chl{sup {minus}1} {center dot} h{sup {minus}1} higher than land-fast ice algae but similar to Antarctic phytoplankton. Primary production in the pack ice during winter may be minor compared to annual phytoplankton production, but could represent a vital seasonal contribution to the Antarctic ecosystem. Nutrient supply may limit the productivity of ice algae. In McMurdo Sound, congelation ice algae appeared to be more nutrient deficient than underlying platelet ice algae based on: lower nitrogen:carbon, chlorophyll:carbon, and protein:carbohydrate; and {sup 14}C-photosynthate distribution to proteins and phospholipids was lower, while distribution to polysaccharides and neutral lipids was higher. Depletion of nitrate led to decreased nitrogen:carbon, chlorophyll:carbon, protein:carbohydrate, and {sup 14}C-photosynthate to proteins. Studied were conducted during the spring bloom; therefore, nutrient limitation may only apply to dense ice algal communities. Growth limiting conditions may be alleviated when algae are released into seawater during the seasonal recession of the ice cover. To continue growth, algae must adapt to the variable light field encountered in a mixed water column. Photoadaptation was studied in surface ice communities and in bottom ice communities.

  19. Activated chemical defenses suppress herbivory on freshwater red algae.

    PubMed

    Goodman, Keri M; Hay, Mark E

    2013-04-01

    The rapid life cycles of freshwater algae are hypothesized to suppress selection for chemical defenses against herbivores, but this notion remains untested. Investigations of chemical defenses are rare for freshwater macrophytes and absent for freshwater red algae. We used crayfish to assess the palatability of five freshwater red algae relative to a palatable green alga and a chemically defended aquatic moss. We then assessed the roles of structural, nutritional, and chemical traits in reducing palatability. Both native and non-native crayfish preferred the green alga Cladophora glomerata to four of the five red algae. Batrachospermum helminthosum, Kumanoa holtonii, and Tuomeya americana employed activated chemical defenses that suppressed feeding by 30-60 % following damage to algal tissues. Paralemanea annulata was defended by its cartilaginous structure, while Boldia erythrosiphon was palatable. Activated defenses are thought to reduce ecological costs by expressing potent defenses only when actually needed; thus, activation might be favored in freshwater red algae whose short-lived gametophytes must grow and reproduce rapidly over a brief growing season. The frequency of activated chemical defenses found here (three of five species) is 3-20× higher than for surveys of marine algae or aquatic vascular plants. If typical for freshwater red algae, this suggests that (1) their chemical defenses may go undetected if chemical activation is not considered and (2) herbivory has been an important selective force in the evolution of freshwater Rhodophyta. Investigations of defenses in freshwater rhodophytes contribute to among-system comparisons and provide insights into the generality of plant-herbivore interactions and their evolution.

  20. Photobiological hydrogen production with switchable photosystem-II designer algae

    DOEpatents

    Lee, James Weifu

    2014-02-18

    A process for enhanced photobiological H.sub.2 production using transgenic alga. The process includes inducing exogenous genes in a transgenic alga by manipulating selected environmental factors. In one embodiment inducing production of an exogenous gene uncouples H.sub.2 production from existing mechanisms that would downregulate H.sub.2 production in the absence of the exogenous gene. In other embodiments inducing an exogenous gene triggers a cascade of metabolic changes that increase H.sub.2 production. In some embodiments the transgenic alga are rendered non-regenerative by inducing exogenous transgenes for proton channel polypeptides that are targeted to specific algal membranes.

  1. Application of synthetic biology in cyanobacteria and algae

    PubMed Central

    Wang, Bo; Wang, Jiangxin; Zhang, Weiwen; Meldrum, Deirdre R.

    2012-01-01

    Cyanobacteria and algae are becoming increasingly attractive cell factories for producing renewable biofuels and chemicals due to their ability to capture solar energy and CO2 and their relatively simple genetic background for genetic manipulation. Increasing research efforts from the synthetic biology approach have been made in recent years to modify cyanobacteria and algae for various biotechnological applications. In this article, we critically review recent progresses in developing genetic tools for characterizing or manipulating cyanobacteria and algae, the applications of genetically modified strains for synthesizing renewable products such as biofuels and chemicals. In addition, the emergent challenges in the development and application of synthetic biology for cyanobacteria and algae are also discussed. PMID:23049529

  2. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production. PMID:27598569

  3. Colourful Cultures: Classroom Experiments with the Unicellular Alga Haematococcus pluvialis.

    ERIC Educational Resources Information Center

    Delpech, Roger

    2001-01-01

    Describes an investigation into the photosynthetic potential of the different developmental stages of the green unicellular alga Haematococcus pluvialis. Reviews the biotechnological applications of astaxanthin, the red pigment which can be extracted from Haematococcus pluvialis. (Author/MM)

  4. Bicarbonate produced from carbon capture for algae culture.

    PubMed

    Chi, Zhanyou; O'Fallon, James V; Chen, Shulin

    2011-11-01

    Using captured CO(2) to grow microalgae is limited by the high cost of CO(2) capture and transportation, as well as significant CO(2) loss during algae culture. Moreover, algae grow poorly at night, but CO(2) cannot be temporarily stored until sunrise. To address these challenges, we discuss a process where CO(2) is captured as bicarbonate and used as feedstock for algae culture, and the carbonate regenerated by the culture process is used as an absorbent to capture more CO(2). This process would significantly reduce carbon capture costs because it does not require additional energy for carbonate regeneration. Furthermore, not only would transport of the aqueous bicarbonate solution cost less than for that of compressed CO(2), but using bicarbonate would also provide a superior alternative for CO(2) delivery to an algae culture system.

  5. CONTROL TECHNOLOGY EXTRACTION OF MERCURY FROM GROUNDWATER IMMOBILIZED ALGAE

    EPA Science Inventory

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contamina...

  6. Harmful algae blooms removal from fresh water with modified vermiculite.

    PubMed

    Miao, Chunguang; Tang, Yi; Zhang, Hong; Wu, Zhengyan; Wang, Xiangqin

    2014-01-01

    Vermiculite and vermiculite modified with hydrochloric acid were investigated to evaluate their flocculation efficiencies in freshwater containing harmful algae blooms (HABs) (Microcystis aeruginosa). Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, converted fluorescence microscope, plasma-atomic emission spectrometry, and Zetasizer were used to study the flocculation mechanism of modified vermiculite. It was found that the vermiculite modified with hydrochloric acid could coagulate algae cells through charge neutralization, chemical bridging, and netting effect. The experimental results show that the efficiency of flocculation can be notably improved by modified vermiculite. Ninety-eight per cent of algae cells in algae solution could be removed within 10 min after the addition ofmodified vermiculite clay. The method that removal of HABs with modified vermiculite is economical with high efficiency, and more research is needed to assess their ecological impacts before using in practical application.

  7. Evaluation of filamentous green algae as feedstocks for biofuel production.

    PubMed

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production.

  8. Photobiological hydrogen production in green algae and photosynthetic bacteria

    SciTech Connect

    Greenbaum, E.

    1986-01-01

    We have shown that, under appropriate physiological conditions, certain freshwater and marine green algae are capable of splitting water to molecular hydrogen and oxygen in a sustained steady-state reaction. In these algae, the gaseous-fuel-producing reaction can be driven by light throughout the visible portion of the solar emission spectrum, including the long wavelength (red) 700-nm region. No external energy sources are required.

  9. Algae Reefs in Shark Bay, Western Australia, Australia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

  10. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential. PMID:22681590

  11. Development of Green Fuels From Algae - The University of Tulsa

    SciTech Connect

    Crunkleton, Daniel; Price, Geoffrey; Johannes, Tyler; Cremaschi, Selen

    2012-12-03

    The general public has become increasingly aware of the pitfalls encountered with the continued reliance on fossil fuels in the industrialized world. In response, the scientific community is in the process of developing non-fossil fuel technologies that can supply adequate energy while also being environmentally friendly. In this project, we concentrate on green fuels which we define as those capable of being produced from renewable and sustainable resources in a way that is compatible with the current transportation fuel infrastructure. One route to green fuels that has received relatively little attention begins with algae as a feedstock. Algae are a diverse group of aquatic, photosynthetic organisms, generally categorized as either macroalgae (i.e. seaweed) or microalgae. Microalgae constitute a spectacularly diverse group of prokaryotic and eukaryotic unicellular organisms and account for approximately 50% of global organic carbon fixation. The PI's have subdivided the proposed research program into three main research areas, all of which are essential to the development of commercially viable algae fuels compatible with current energy infrastructure. In the fuel development focus, catalytic cracking reactions of algae oils is optimized. In the species development project, genetic engineering is used to create microalgae strains that are capable of high-level hydrocarbon production. For the modeling effort, the construction of multi-scaled models of algae production was prioritized, including integrating small-scale hydrodynamic models of algae production and reactor design and large-scale design optimization models.

  12. Extraction of mercury from ground-water using immobilized algae

    SciTech Connect

    Barkley, N.P.

    1991-01-01

    Bio-recovery Systems Inc., conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to absorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algae biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into absorption columns, exhibited excellent flow characteristics, and functioned as a 'biological' ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of the product to absorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded non-repeatable results with samples collected at different times of the year. The strategy of extracting the groundwater through two columns containing different times of the year. The strategy of extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity. (Copyright (c) 1991--Air and Waste Management Association.)

  13. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  14. Modelling the effect of fluctuating herbicide concentrations on algae growth.

    PubMed

    Copin, Pierre-Jean; Coutu, Sylvain; Chèvre, Nathalie

    2015-03-01

    Herbicide concentrations fluctuate widely in watercourses after crop applications and rain events. The level of concentrations in pulses can exceed the water chronic quality criteria. In the present study, we proposed modelling the effects of successive pulse exposure on algae. The deterministic model proposed is based on two parameters: (i) the typical growth rate of the algae, obtained by monitoring growth rates of several successive batch cultures in growth media, characterizing both the growth of the control and during the recovery periods; (ii) the growth rate of the algae exposed to pulses, determined from a dose-response curve obtained with a standard toxicity test. We focused on the herbicide isoproturon and on the freshwater alga Scenedesmus vacuolatus, and we validated the model prediction based on effect measured during five sequential pulse exposures in laboratory. The comparison between the laboratory and the modelled effects illustrated that the results yielded were consistent, making the model suitable for effect prediction of the herbicide photosystem II inhibitor isoproturon on the alga S. vacuolatus. More generally, modelling showed that both pulse duration and level of concentration play a crucial role. The application of the model to a real case demonstrated that both the highest peaks and the low peaks with a long duration affect principally the cell density inhibition of the alga S. vacuolatus. It is therefore essential to detect these characteristic pulses when monitoring of herbicide concentrations are conducted in rivers. PMID:25499055

  15. An overview of algae biofuel production and potential environmental impact.

    PubMed

    Menetrez, Marc Y

    2012-07-01

    Algae are among the most potentially significant sources of sustainable biofuels in the future of renewable energy. A feedstock with virtually unlimited applicability, algae can metabolize various waste streams (e.g., municipal wastewater, carbon dioxide from industrial flue gas) and produce products with a wide variety of compositions and uses. These products include lipids, which can be processed into biodiesel; carbohydrates, which can be processed into ethanol; and proteins, which can be used for human and animal consumption. Algae are commonly genetically engineered to allow for advantageous process modification or optimization. However, issues remain regarding human exposure to algae-derived toxins, allergens, and carcinogens from both existing and genetically modified organisms (GMOs), as well as the overall environmental impact of GMOs. A literature review was performed to highlight issues related to the growth and use of algal products for generating biofuels. Human exposure and environmental impact issues are identified and discussed, as well as current research and development activities of academic, commercial, and governmental groups. It is hoped that the ideas contained in this paper will increase environmental awareness of issues surrounding the production of algae and will help the algae industry develop to its full potential.

  16. Radionuclides and trace metals in eastern Mediterranean Sea algae.

    PubMed

    Al-Masri, M S; Mamish, S; Budier, Y

    2003-01-01

    Three types of sea alga distributed along the Syrian coast have been collected and analyzed for radioactivity and trace elements. Results have shown that (137)Cs concentrations in all the analyzed sample were relatively low (less than 1.2 Bq kg(-1) dry weight) while the levels of naturally occurring radionuclides, such as (210)Po and (210)Pb, were found to be high in most samples; the highest observed value (27.43 Bq kg(-1) dry weight) for (210)Po being in the red Jania longifurca alga. In addition, most brown alga species were also found to accumulate (210)Po, which indicates their selectivity to this isotope. On the other hand, brown alga (Cystoseira and Sargassum Vulgare) have shown a clear selectivity for some trace metals such as Cr, As, Cu and Co, this selectivity may encourage their use as biomonitor for pollution by trace metals. Moreover, the red alga species were found to contain the highest levels of Mg while the brown alga species were found to concentrate Fe, Mn, Na and K and nonmetals such as Cl, I and Br. PMID:12660047

  17. Feeding preferences of mesograzers on aquacultured Gracilaria and sympatric algae

    PubMed Central

    Cruz-Rivera, Edwin; Friedlander, Michael

    2011-01-01

    While large grazers can often be excluded effectively from algal aquaculture operations, smaller herbivores such as small crustaceans and gastropods may be more difficult to control. The susceptibility of three Gracilaria species to herbivores was evaluated in multiple-choice experiments with the amphipod Ampithoe ramondi and the crab Acanthonyx lunulatus. Both mesograzers are common along the Mediterranean coast of Israel. When given a choice, the amphipod preferred to consume Gracilaria lemaneiformis significantly more than either G. conferta or G. cornea. The crab, however, consumed equivalent amounts of G. lemaneiformis and G. conferta, but did not consume G. cornea. Organic content of these algae, an important feeding cue for some mesograzers, could not account for these differences. We further assessed the susceptibility of a candidate species for aquaculture, G. lemaneiformis, against local algae, including common epiphytes. When given a choice of four algae, amphipods preferred the green alga Ulva lactuca over Jania rubens. However, consumption of U. lactuca was equivalent to those of G. lemaneiformis and Padina pavonica. In contrast, the crab showed a marked and significant preference for G. lemaneiformis above any of the other three algae offered. Our results suggest that G. cornea is more resistant to herbivory from common mesograzers and that, contrary to expectations, mixed cultures or epiphyte growth on G. lemaneiformis cannot reduce damage to this commercially appealing alga if small herbivores are capable of recruiting into culture ponds. Mixed cultures may be beneficial when culturing other Gracilaria species. PMID:22711945

  18. VEGA/CHARA interferometric observations of Cepheids. I. A resolved structure around the prototype classical Cepheid δ Cep in the visible spectral range

    NASA Astrophysics Data System (ADS)

    Nardetto, N.; Mérand, A.; Mourard, D.; Storm, J.; Gieren, W.; Fouqué, P.; Gallenne, A.; Graczyk, D.; Kervella, P.; Neilson, H.; Pietrzynski, G.; Pilecki, B.; Breitfelder, J.; Berio, P.; Challouf, M.; Clausse, J.-M.; Ligi, R.; Mathias, P.; Meilland, A.; Perraut, K.; Poretti, E.; Rainer, M.; Spang, A.; Stee, P.; Tallon-Bosc, I.; ten Brummelaar, T.

    2016-09-01

    Context. The B-W method is used to determine the distance of Cepheids and consists in combining the angular size variations of the star, as derived from infrared surface-brightness relations or interferometry, with its linear size variation, as deduced from visible spectroscopy using the projection factor. The underlying assumption is that the photospheres probed in the infrared and in the visible are located at the same layer in the star whatever the pulsation phase. While many Cepheids have been intensively observed by infrared beam combiners, only a few have been observed in the visible. Aims: This paper is part of a project to observe Cepheids in the visible with interferometry as a counterpart to infrared observations already in hand. Methods: Observations of δ Cep itself were secured with the VEGA/CHARA instrument over the full pulsation cycle of the star. Results: These visible interferometric data are consistent in first approximation with a quasi-hydrostatic model of pulsation surrounded by a static circumstellar environment (CSE) with a size of θCSE = 8.9 ± 3.0 mas and a relative flux contribution of fCSE = 0.07 ± 0.01. A model of visible nebula (a background source filling the field of view of the interferometer) with the same relative flux contribution is also consistent with our data at small spatial frequencies. However, in both cases, we find discrepancies in the squared visibilities at high spatial frequencies (maximum 2σ) with two different regimes over the pulsation cycle of the star, φ = 0.0 - 0.8 and φ = 0.8-1.0. We provide several hypotheses to explain these discrepancies, but more observations and theoretical investigations are necessary before a firm conclusion can be drawn. Conclusions: For the first time we have been able to detect in the visible domain a resolved structure around δ Cep. We have also shown that a simple model cannot explain the observations, and more work will be necessary in the future, both on observations and

  19. A near-infrared interferometric survey of debris-disc stars. III. First statistics based on 42 stars observed with CHARA/FLUOR

    NASA Astrophysics Data System (ADS)

    Absil, O.; Defrère, D.; Coudé du Foresto, V.; Di Folco, E.; Mérand, A.; Augereau, J.-C.; Ertel, S.; Hanot, C.; Kervella, P.; Mollier, B.; Scott, N.; Che, X.; Monnier, J. D.; Thureau, N.; Tuthill, P. G.; ten Brummelaar, T. A.; McAlister, H. A.; Sturmann, J.; Sturmann, L.; Turner, N.

    2013-07-01

    Context. Dust is expected to be ubiquitous in extrasolar planetary systems owing to the dynamical activity of minor bodies. Inner dust populations are, however, still poorly known because of the high contrast and small angular separation with respect to their host star, and yet, a proper characterisation of exozodiacal dust is mandatory for the design of future Earth-like planet imaging missions. Aims: We aim to determine the level of near-infrared exozodiacal dust emission around a sample of 42 nearby main sequence stars with spectral types ranging from A to K and to investigate its correlation with various stellar parameters and with the presence of cold dust belts. Methods: We use high-precision K-band visibilities obtained with the FLUOR interferometer on the shortest baseline of the CHARA array. The calibrated visibilities are compared with the expected visibility of the stellar photosphere to assess whether there is an additional, fully resolved circumstellar emission source. Results: Near-infrared circumstellar emission amounting to about 1% of the stellar flux is detected around 13 of our 42 target stars. Follow-up observations showed that one of them (eps Cep) is associated with a stellar companion, while another one was detected around what turned out to be a giant star (kap CrB). The remaining 11 excesses found around single main sequence stars are most probably associated with hot circumstellar dust, yielding an overall occurrence rate of 28+8-6 for our (biased) sample. We show that the occurrence rate of bright exozodiacal discs correlates with spectral type, K-band excesses being more frequent around A-type stars. It also correlates with the presence of detectable far-infrared excess emission in the case of solar-type stars. Conclusions: This study provides new insight into the phenomenon of bright exozodiacal discs, showing that hot dust populations are probably linked to outer dust reservoirs in the case of solar-type stars. For A-type stars, no

  20. Phosphorus-limited growth of a green alga and a blue-green alga

    SciTech Connect

    Lang, D.S.; Brown, E.J.

    1981-12-01

    The phosphorus-limited growth kinetics of the chlorophyte Scenedesmus quadricauda and the cyanophyte Synechococcus Nageli were studied by using batch and continuous culturing techniques. The steady-state phosphate transport capability and the phosphorus storage capacity is higher in S. Nageli than in S. quadricauda. Synechococcus Nageli can also deplete phosphate to much lower levels than can S. quadricauda. These results, along with their morphological characteristics, were used to construct partial physiological profiles for each organism. The profiles indicate that this unicellular cyanophyte (cyanobacterium) is better suited for growth in phosphorus-limited oligotrophic niches than is this chlorophyte (green alga). (Refs. 44).

  1. Comparative Transcriptome Analysis of Four Prymnesiophyte Algae

    PubMed Central

    Koid, Amy E.; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C.; Caron, David A.; Heidelberg, Karla B.

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists. PMID:24926657

  2. Microfluidic one-way streets for algae

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Goldstein, Raymond E.

    2012-02-01

    Controlling locomotion and transport of microorganisms is a key challenge in the development of future biotechnological applications. Here, we demonstrate the use of optimized microfluidic ratchets to rectify the mean swimming direction in suspensions of the unicellular green alga Chlamydomonas reinhardtii, which is a promising candidate for the photosynthetic production of hydrogen. To assess the potential of microfluidic barriers for the manipulation of algal swimming, we studied first the scattering of individual C. reinhardtii from solid boundaries. High-speed imaging reveals the surprising result that these quasi-spherical ``puller''-type microswimmers primarily interact with surfaces via direct flagellar contact, whereas hydrodynamic effects play a subordinate role. A minimal theoretical model, based on run-and-turn motion and the experimentally measured surface-scattering law, predicts the existence of optimal wedge-shaped ratchets that maximize rectification of initially uniform suspensions. We confirm this prediction in experimental measurements with different geometries. Since the mechano-elastic properties of eukaryotic flagella are conserved across many genera, we expect that our results and methods are applicable to a broad class of biflagellate microorganisms.

  3. Mixotrophy in red tide algae raphidophytes.

    PubMed

    Jeong, Hae Jin

    2011-01-01

    Marine raphidophytes are common red tide organisms that are distributed worldwide. They are known to be harmful to other plankton and fish and have often caused large-scale fish mortality in many countries. Thus, the population dynamics of raphidophytes is a critical concern for scientists, the aquaculture industry, and government officers from many countries. Raphidophyte growth and mortality should be investigated to understand bloom dynamics. Raphidophytes were thought to be exclusively autotrophic organisms. However, several recent studies have revealed that raphidophytes are able to feed on heterotrophic and autotrophic bacteria, i.e. raphidophytes are mixotrophic algae. Further, high-resolution video microscopy has revealed the mechanism by which raphidophytes feed on bacteria, which involves capturing prey cells in the mucus excreted by mucocysts and engulfing the cells through mucocysts. These discoveries may influence the conventional view on both raphidophyte bloom dynamics and plankton energy flow and carbon cycling. In the present study, I review prey, feeding mechanisms, and ingestion rates of mixotrophic marine raphidophytes. In addition, I examine the ecological significance of raphidophyte mixotrophy.

  4. Comparative transcriptome analysis of four prymnesiophyte algae.

    PubMed

    Koid, Amy E; Liu, Zhenfeng; Terrado, Ramon; Jones, Adriane C; Caron, David A; Heidelberg, Karla B

    2014-01-01

    Genomic studies of bacteria, archaea and viruses have provided insights into the microbial world by unveiling potential functional capabilities and molecular pathways. However, the rate of discovery has been slower among microbial eukaryotes, whose genomes are larger and more complex. Transcriptomic approaches provide a cost-effective alternative for examining genetic potential and physiological responses of microbial eukaryotes to environmental stimuli. In this study, we generated and compared the transcriptomes of four globally-distributed, bloom-forming prymnesiophyte algae: Prymnesium parvum, Chrysochromulina brevifilum, Chrysochromulina ericina and Phaeocystis antarctica. Our results revealed that the four transcriptomes possess a set of core genes that are similar in number and shared across all four organisms. The functional classifications of these core genes using the euKaryotic Orthologous Genes (KOG) database were also similar among the four study organisms. More broadly, when the frequencies of different cellular and physiological functions were compared with other protists, the species clustered by both phylogeny and nutritional modes. Thus, these clustering patterns provide insight into genomic factors relating to both evolutionary relationships as well as trophic ecology. This paper provides a novel comparative analysis of the transcriptomes of ecologically important and closely related prymnesiophyte protists and advances an emerging field of study that uses transcriptomics to reveal ecology and function in protists.

  5. Is the Future Really in Algae?

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan

    2011-01-01

    Having just emerged from the warmest decade on record and watching as the oceans acidify, global resources peak, the world's population continues to climb, and nearly half of all known species face extinction by the end of the century. We stand on the threshold of one of the most important transition in human history-the transition from hunting-and-gathering our energy to cultivating sustainable, carbon-neutral, environmentally-friendly energy supplies. Can we "cultivate" enerm without competing with agriculture for land, freshwater, or fertilizer? Can we develop an "ecology of technology" that optimizes our use of limited resources? Is human activity compatible with improved conditions in the world's oceans? Will our ingenuity prevail in time to make a difference for our children and the children of all species? With support from NASA ARMD and the California Energy Commission, a group of dedicated scientists and engineers are working on a project called OMEGA (Offshore Membrane Enclosures for Growing Algae), to provide practical answers to these critical questions and to leave a legacy of hope for the oceans and for the future.

  6. Two-step evolution of endosymbiosis between hydra and algae.

    PubMed

    Ishikawa, Masakazu; Shimizu, Hiroshi; Nozawa, Masafumi; Ikeo, Kazuho; Gojobori, Takashi

    2016-10-01

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians. PMID:27404042

  7. Two-step evolution of endosymbiosis between hydra and algae.

    PubMed

    Ishikawa, Masakazu; Shimizu, Hiroshi; Nozawa, Masafumi; Ikeo, Kazuho; Gojobori, Takashi

    2016-10-01

    In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians.

  8. Plasticity predicts evolution in a marine alga.

    PubMed

    Schaum, C Elisa; Collins, Sinéad

    2014-10-22

    Under global change, populations have four possible responses: 'migrate, acclimate, adapt or die' (Gienapp et al. 2008 Climate change and evolution: disentangling environmental and genetic response. Mol. Ecol. 17, 167-178. (doi:10.1111/j.1365-294X.2007.03413.x)). The challenge is to predict how much migration, acclimatization or adaptation populations are capable of. We have previously shown that populations from more variable environments are more plastic (Schaum et al. 2013 Variation in plastic responses of a globally distributed picoplankton species to ocean acidification. Nature 3, 298-230. (doi:10.1038/nclimate1774)), and here we use experimental evolution with a marine microbe to learn that plastic responses predict the extent of adaptation in the face of elevated partial pressure of CO2 (pCO2). Specifically, plastic populations evolve more, and plastic responses in traits other than growth can predict changes in growth in a marine microbe. The relationship between plasticity and evolution is strongest when populations evolve in fluctuating environments, which favour the evolution and maintenance of plasticity. Strikingly, plasticity predicts the extent, but not direction of phenotypic evolution. The plastic response to elevated pCO2 in green algae is to increase cell division rates, but the evolutionary response here is to decrease cell division rates over 400 generations until cells are dividing at the same rate their ancestors did in ambient CO2. Slow-growing cells have higher mitochondrial potential and withstand further environmental change better than faster growing cells. Based on this, we hypothesize that slow growth is adaptive under CO2 enrichment when associated with the production of higher quality daughter cells.

  9. Anti-Phytopathogenic Activities of Macro-Algae Extracts

    PubMed Central

    Jiménez, Edra; Dorta, Fernando; Medina, Cristian; Ramírez, Alberto; Ramírez, Ingrid; Peña-Cortés, Hugo

    2011-01-01

    Aqueous and ethanolic extracts obtained from nine Chilean marine macro-algae collected at different seasons were examined in vitro and in vivo for properties that reduce the growth of plant pathogens or decrease the injury severity of plant foliar tissues following pathogen infection. Particular crude aqueous or organic extracts showed effects on the growth of pathogenic bacteria whereas others displayed important effects against pathogenic fungi or viruses, either by inhibiting fungal mycelia growth or by reducing the disease symptoms in leaves caused by pathogen challenge. Organic extracts obtained from the brown-alga Lessonia trabeculata inhibited bacterial growth and reduced both the number and size of the necrotic lesion in tomato leaves following infection with Botrytis cinerea. Aqueous and ethanolic extracts from the red-alga Gracillaria chilensis prevent the growth of Phytophthora cinnamomi, showing a response which depends on doses and collecting-time. Similarly, aqueous and ethanolic extracts from the brown-alga Durvillaea antarctica were able to diminish the damage caused by tobacco mosaic virus (TMV) in tobacco leaves, and the aqueous procedure is, in addition, more effective and seasonally independent. These results suggest that macro-algae contain compounds with different chemical properties which could be considered for controlling specific plant pathogens. PMID:21673886

  10. Boron uptake, localization, and speciation in marine brown algae.

    PubMed

    Miller, Eric P; Wu, Youxian; Carrano, Carl J

    2016-02-01

    In contrast to the generally boron-poor terrestrial environment, the concentration of boron in the marine environment is relatively high (0.4 mM) and while there has been extensive interest in its use as a surrogate of pH in paleoclimate studies in the context of climate change-related questions, the relatively depth independent, and the generally non-nutrient-like concentration profile of this element have led to boron being neglected as a potentially biologically relevant element in the ocean. Among the marine plant-like organisms the brown algae (Phaeophyta) are one of only five lineages of photosynthetic eukaryotes to have evolved complex multicellularity. Many of unusual and often unique features of brown algae are attributable to this singular evolutionary history. These adaptations are a reflection of the marine coastal environment which brown algae dominate in terms of biomass. Consequently, brown algae are of fundamental importance to oceanic ecology, geochemistry, and coastal industry. Our results indicate that boron is taken up by a facilitated diffusion mechanism against a considerable concentration gradient. Furthermore, in both Ectocarpus and Macrocystis some boron is most likely bound to cell wall constituent alginate and the photoassimilate mannitol located in sieve cells. Herein, we describe boron uptake, speciation, localization and possible biological function in two species of brown algae, Macrocystis pyrifera and Ectocarpus siliculosus. PMID:26679972

  11. Visualization of oxygen distribution patterns caused by coral and algae.

    PubMed

    Haas, Andreas F; Gregg, Allison K; Smith, Jennifer E; Abieri, Maria L; Hatay, Mark; Rohwer, Forest

    2013-01-01

    Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp.) and a hermatypic coral (Favia sp.) separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 ± 7.7 µmol O2 L(- 1)) and daylight (97.9 ± 27.5 µmol O2 L(- 1)) conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones.

  12. Application of algae-biosensor for environmental monitoring.

    PubMed

    Umar, Lazuardi; Alexander, Frank A; Wiest, Joachim

    2015-01-01

    Environmental problems including water and air pollution, over fertilization, insufficient wastewater treatment and even ecological disaster are receiving greater attention in the technical and scientific area. In this paper, a method for water quality monitoring using living green algae (Chlorella Kessleri) with the help of the intelligent mobile lab (IMOLA) is presented. This measurement used two IMOLA systems for measurement and reference simultaneously to verify changes due to pollution inside the measurement system. The IMOLA includes light emitting diodes to stimulate photosynthesis of the living algae immobilized on a biochip containing a dissolved oxygen microsensor. A fluid system is used to transport algae culture medium in a stop and go mode; 600s ON, 300s OFF, while the oxygen concentration of the water probe is measured. When the pump stops, the increase in dissolved oxygen concentration due to photosynthesis is detected. In case of a pollutant being transported toward the algae, this can be detected by monitoring the photosynthetic activity. Monitoring pollution is shown by adding emulsion of 0,5mL of Indonesian crude palm oil and 10mL algae medium to the water probe in the biosensor.

  13. Extraction of mercury from groundwater using immobilized algae

    SciTech Connect

    Barkley, N.P. )

    1991-10-01

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a biological ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity.

  14. Algae-bacteria interactions: Evolution, ecology and emerging applications.

    PubMed

    Ramanan, Rishiram; Kim, Byung-Hyuk; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2016-01-01

    Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae-roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal-bacterial interactions to various environmental and bio-technological applications. PMID:26657897

  15. Extraction of mercury from groundwater using immobilized algae.

    PubMed

    Barkley, N P

    1991-10-01

    Bio-Recovery Systems, Inc. conducted a project under the Emerging Technology portion of the United States Environmental Protection Agency's (EPAs) Superfund Innovative Technology Evaluation (SITE) Program to evaluate the ability of immobilized algae to adsorb mercury from contaminated groundwater in laboratory studies and pilot-scale field tests. Algal biomass was incorporated in a permeable polymeric matrix. The product, AlgaSORB, packed into adsorption columns, exhibited excellent flow characteristics, and functioned as a "biological" ion exchange resin. A sequence of eleven laboratory tests demonstrated the ability of this product to adsorb mercury from groundwater that contained high levels of total dissolved solids and hard water components. However, use of a single AlgaSORB preparation yielded nonrepeatable results with samples collected at different times of the year. The strategy of sequentially extracting the groundwater through two columns containing different preparations of AlgaSORB was developed and proved successful in laboratory and pilot-scale field tests. Field test results indicate that AlgaSORB could be economically competitive with ion exchange resins for removal of mercury, with the advantage that hardness and other dissolved solids do not appear to compete with heavy metals for binding capacity. PMID:1777231

  16. Actin gene family dynamics in cryptomonads and red algae.

    PubMed

    Tanifuji, Goro; Archibald, John M

    2010-09-01

    Here we present evidence for a complex evolutionary history of actin genes in red algae and cryptomonads, a group that acquired photosynthesis secondarily through the engulfment of a red algal endosymbiont. Four actin genes were found in the nuclear genome of the cryptomonad, Guillardia theta, and in the genome of the red alga, Galdieria sulphuraria, a member of the Cyanidiophytina. Phylogenetic analyses reveal that the both organisms possess two distinct sequence types, designated "type-1" and "type-2." A weak but consistent phylogenetic affinity between the cryptomonad type-2 sequences and the type-2 sequences of G. sulphuraria and red algae belonging to the Rhodophytina was observed. This is consistent with the possibility that the cryptomonad type-2 sequences are derived from the red algal endosymbiont that gave rise to the cryptomonad nucleomorph and plastid. Red algae as a whole possess two very different actin sequence types, with G. sulphuraria being the only organism thus far known to possess both. The common ancestor of Rhodophytina and Cyanidiophytina may have had two actin genes, with differential loss explaining the distribution of these genes in modern-day groups. Our study provides new insight into the evolution and divergence of actin genes in cryptomonads and red algae, and in doing so underscores the challenges associated with heterogeneity in actin sequence evolution and ortholog/paralog detection.

  17. Boron uptake, localization, and speciation in marine brown algae.

    PubMed

    Miller, Eric P; Wu, Youxian; Carrano, Carl J

    2016-02-01

    In contrast to the generally boron-poor terrestrial environment, the concentration of boron in the marine environment is relatively high (0.4 mM) and while there has been extensive interest in its use as a surrogate of pH in paleoclimate studies in the context of climate change-related questions, the relatively depth independent, and the generally non-nutrient-like concentration profile of this element have led to boron being neglected as a potentially biologically relevant element in the ocean. Among the marine plant-like organisms the brown algae (Phaeophyta) are one of only five lineages of photosynthetic eukaryotes to have evolved complex multicellularity. Many of unusual and often unique features of brown algae are attributable to this singular evolutionary history. These adaptations are a reflection of the marine coastal environment which brown algae dominate in terms of biomass. Consequently, brown algae are of fundamental importance to oceanic ecology, geochemistry, and coastal industry. Our results indicate that boron is taken up by a facilitated diffusion mechanism against a considerable concentration gradient. Furthermore, in both Ectocarpus and Macrocystis some boron is most likely bound to cell wall constituent alginate and the photoassimilate mannitol located in sieve cells. Herein, we describe boron uptake, speciation, localization and possible biological function in two species of brown algae, Macrocystis pyrifera and Ectocarpus siliculosus.

  18. Method to transform algae, materials therefor, and products produced thereby

    DOEpatents

    Dunahay, T.G.; Roessler, P.G.; Jarvis, E.E.

    1997-08-26

    Disclosed is a method to transform chlorophyll C-containing algae. The method includes introducing a recombinant molecule comprising a nucleic acid molecule encoding a dominant selectable marker operatively linked to an algal regulatory control sequence into a chlorophyll C-containing alga in such a manner that the marker is produced by the alga. In a preferred embodiment the algal regulatory control sequence is derived from a diatom and preferably Cyclotella cryptica. Also disclosed is a chimeric molecule having one or more regulatory control sequences derived from one or more chlorophyll C-containing algae operatively linked to a nucleic acid molecule encoding a selectable marker, an RNA molecule and/or a protein, wherein the nucleic acid molecule does not normally occur with one or more of the regulatory control sequences. Further, specifically disclosed are molecules pACCNPT10, pACCNPT4.8 and pACCNPT5.1. The methods and materials of the present invention provide the ability to accomplish stable genetic transformation of chlorophyll C-containing algae. 2 figs.

  19. Method to transform algae, materials therefor, and products produced thereby

    DOEpatents

    Dunahay, Terri Goodman; Roessler, Paul G.; Jarvis, Eric E.

    1997-01-01

    Disclosed is a method to transform chlorophyll C-containing algae which includes introducing a recombinant molecule comprising a nucleic acid molecule encoding a dominant selectable marker operatively linked to an algal regulatory control sequence into a chlorophyll C-containing alga in such a manner that the marker is produced by the alga. In a preferred embodiment the algal regulatory control sequence is derived from a diatom and preferably Cyclotella cryptica. Also disclosed is a chimeric molecule having one or more regulatory control sequences derived from one or more chlorophyll C-containing algae operatively linked to a nucleic acid molecule encoding a selectable marker, an RNA molecule and/or a protein, wherein the nucleic acid molecule does not normally occur with one or more of the regulatory control sequences. Further specifically disclosed are molecules pACCNPT10, pACCNPT4.8 and pACCNPT5.1. The methods and materials of the present invention provide the ability to accomplish stable genetic transformation of chlorophyll C-containing algae.

  20. Algae-bacteria interactions: Evolution, ecology and emerging applications.

    PubMed

    Ramanan, Rishiram; Kim, Byung-Hyuk; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2016-01-01

    Algae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions - from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae-roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal-bacterial interactions to various environmental and bio-technological applications.

  1. Application of algae-biosensor for environmental monitoring.

    PubMed

    Umar, Lazuardi; Alexander, Frank A; Wiest, Joachim

    2015-01-01

    Environmental problems including water and air pollution, over fertilization, insufficient wastewater treatment and even ecological disaster are receiving greater attention in the technical and scientific area. In this paper, a method for water quality monitoring using living green algae (Chlorella Kessleri) with the help of the intelligent mobile lab (IMOLA) is presented. This measurement used two IMOLA systems for measurement and reference simultaneously to verify changes due to pollution inside the measurement system. The IMOLA includes light emitting diodes to stimulate photosynthesis of the living algae immobilized on a biochip containing a dissolved oxygen microsensor. A fluid system is used to transport algae culture medium in a stop and go mode; 600s ON, 300s OFF, while the oxygen concentration of the water probe is measured. When the pump stops, the increase in dissolved oxygen concentration due to photosynthesis is detected. In case of a pollutant being transported toward the algae, this can be detected by monitoring the photosynthetic activity. Monitoring pollution is shown by adding emulsion of 0,5mL of Indonesian crude palm oil and 10mL algae medium to the water probe in the biosensor. PMID:26737928

  2. Method and apparatus using an active ionic liquid for algae biofuel harvest and extraction

    DOEpatents

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2012-11-06

    The invention relates to use of an active ionic liquid to dissolve algae cell walls. The ionic liquid is used to, in an energy efficient manner, dissolve and/or lyse an algae cell walls, which releases algae constituents used in the creation of energy, fuel, and/or cosmetic components. The ionic liquids include ionic salts having multiple charge centers, low, very low, and ultra low melting point ionic liquids, and combinations of ionic liquids. An algae treatment system is described, which processes wet algae in a lysing reactor, separates out algae constituent products, and optionally recovers the ionic liquid in an energy efficient manner.

  3. An updated comprehensive techno-economic analysis of algae biodiesel.

    PubMed

    Nagarajan, Sanjay; Chou, Siaw Kiang; Cao, Shenyan; Wu, Chen; Zhou, Zhi

    2013-10-01

    Algae biodiesel is a promising but expensive alternative fuel to petro-diesel. To overcome cost barriers, detailed cost analyses are needed. A decade-old cost analysis by the U.S. National Renewable Energy Laboratory indicated that the costs of algae biodiesel were in the range of $0.53-0.85/L (2012 USD values). However, the cost of land and transesterification were just roughly estimated. In this study, an updated comprehensive techno-economic analysis was conducted with optimized processes and improved cost estimations. Latest process improvement, quotes from vendors, government databases, and other relevant data sources were used to calculate the updated algal biodiesel costs, and the final costs of biodiesel are in the range of $0.42-0.97/L. Additional improvements on cost-effective biodiesel production around the globe to cultivate algae was also recommended. Overall, the calculated costs seem promising, suggesting that a single step biodiesel production process is close to commercial reality.

  4. Importance of algae as a potential source of biofuel.

    PubMed

    Singh, A K; Singh, M P

    2014-12-24

    Algae have a great potential source of biofuels and also have unique importance to reduce gaseous emissions, greenhouse gases, climatic changes, global warming receding of glaciers, rising sea levels and loss of biodiversity. The microalgae, like Scenedesmus obliquus, Neochloris oleabundans, Nannochloropsis sp., Chlorella emersonii, and Dunaliella tertiolecta have high oil content. Among the known algae, Scenedesmus obliquus is one of the most potential sources for biodiesel as it has adequate fatty acid (linolenic acid) and other polyunsaturated fatty acids. Bio—ethanol is already in the market of United States of America and Europe as an additive in gasoline. Bio—hydrogen is the cleanest biofuel and extensive efforts are going on to bring it to market at economical price. This review highlights recent development and progress in the field of algae as a potential source of biofuel.

  5. Stable chloroplast transformation of the unicellular red alga Porphyridium species.

    PubMed

    Lapidot, Miri; Raveh, Dina; Sivan, Alex; Arad, Shoshana Malis; Shapira, Michal

    2002-05-01

    Red algae are extremely attractive for biotechnology because they synthesize accessory photosynthetic pigments (phycobilins and carotenoids), unsaturated fatty acids, and unique cell wall sulfated polysaccharides. We report a high-efficiency chloroplast transformation system for the unicellular red microalga Porphyridium sp. This is the first genetic transformation system for Rhodophytes and is based on use of a mutant form of the gene encoding acetohydroxyacid synthase [AHAS(W492S)] as a dominant selectable marker. AHAS is the target enzyme of the herbicide sulfometuron methyl, which effectively inhibits growth of bacteria, fungi, plants, and algae. Biolistic transformation of synchronized Porphyridium sp. cells with the mutant AHAS(W492S) gene that confers herbicide resistance gave a high frequency of sulfomethuron methyl-resistant colonies. The mutant AHAS gene integrated into the chloroplast genome by homologous recombination. This system paves the way for expression of foreign genes in red algae and has important biotechnological implications.

  6. [Immunostimulating activity of the lipopolysaccharides of blue-green algae].

    PubMed

    Besednova, N N; Smolina, T P; Mikheĭskaia, L V; Ovodova, R G

    1979-12-01

    The whole cells of blue-gree algae and lipopolysaccharides isolated from these cells were shown to stimulate the production of macro-(mainly) and microglobulin antibodies in rabbits. The macro- and microphage indices in rabbits increased significantly after the injection of LPS isolated from blue-green algae 24--48 hours before infecting the animals with a virulent Y. pseudotuberculosis strain. Besides, the inhibiting action of this strain on the migration of phagocytes to the site of infection was abolished immediately after the injection. The use of the indirect hemagglutination test allowed to prove the absence of close antigenic interrelations between blue-green algae and the following organisms: Spirulina platensis, Microcystis aeruginosa, Phormidium africanum and P. uncinatum. PMID:117655

  7. Algae from the arid southwestern United States: an annotated bibliography

    SciTech Connect

    Thomas, W.H.; Gaines, S.R.

    1983-06-01

    Desert algae are attractive biomass producers for capturing solar energy through photosynthesis of organic matter. They are probably capable of higher yields and efficiencies of light utilization than higher plants, and are already adapted to extremes of sunlight intensity, salinity and temperature such as are found in the desert. This report consists of an annotated bibliography of the literature on algae from the arid southwestern United States. It was prepared in anticipation of efforts to isolate desert algae and study their yields in the laboratory. These steps are necessary prior to setting up outdoor algal culture ponds. Desert areas are attractive for such applications because land, sunlight, and, to some extent, water resources are abundant there. References are sorted by state.

  8. Designer proton-channel transgenic algae for photobiological hydrogen production

    DOEpatents

    Lee, James Weifu

    2011-04-26

    A designer proton-channel transgenic alga for photobiological hydrogen production that is specifically designed for production of molecular hydrogen (H.sub.2) through photosynthetic water splitting. The designer transgenic alga includes proton-conductive channels that are expressed to produce such uncoupler proteins in an amount sufficient to increase the algal H.sub.2 productivity. In one embodiment the designer proton-channel transgene is a nucleic acid construct (300) including a PCR forward primer (302), an externally inducible promoter (304), a transit targeting sequence (306), a designer proton-channel encoding sequence (308), a transcription and translation terminator (310), and a PCR reverse primer (312). In various embodiments, the designer proton-channel transgenic algae are used with a gas-separation system (500) and a gas-products-separation and utilization system (600) for photobiological H.sub.2 production.

  9. A look at diacylglycerol acyltransferases (DGATs) in algae.

    PubMed

    Chen, Jit Ern; Smith, Alison G

    2012-11-30

    Triacylglycerols (TAGs) from algae are considered to be a potentially viable source of biodiesel and thereby renewable energy, but at the moment very little is known about the biosynthetic pathway in these organisms. Here we compare what is currently known in eukaryotic algal species, in particular the characteristics of algal diacylglycerol acyltransferase (DGAT), the last enzyme of de novo TAG biosynthesis. Several studies in plants and mammals have shown that there are two DGAT isoforms, DGAT1 and DGAT2, which catalyse the same reaction but have no clear sequence similarities. Instead, they have differences in functionality and spatial and temporal expression patterns. Bioinformatic searches of sequenced algal genomes reveal that most algae have multiple copies of putative DGAT2s, whereas other eukaryotes have single genes. Investigating whether these putative isoforms are indeed functional and whether they confer significantly different phenotypes to algal cells will be vital for future efforts to genetically modify algae for biofuel production.

  10. Synergistic cooperation between wastewater-born algae and activated sludge for wastewater treatment: influence of algae and sludge inoculation ratios.

    PubMed

    Su, Yanyan; Mennerich, Artur; Urban, Brigitte

    2012-02-01

    An algal-bacterial culture, composed of wastewater-born algae and activated sludge, was cultivated to treat domestic wastewater and accumulate biomass simultaneously. The influence of algae and sludge inoculation ratios on the treatment efficiency and the settleability of the accumulated biomass were investigated. There was no significant effect of the inoculation ratios on the chemical oxygen demand removal. Comparatively, the nutrients removal and related mechanism were varied with different inoculation ratios. The highest nitrogen and phosphorus removal efficiencies were observed with 5:1 (algae/sludge) culture (91.0±7.0% and 93.5±2.5%, respectively) within 10 days, which was 5-40% higher and 2-4 days faster than those with other inoculation ratios. The biomass settleability was improved with the assistance of sludge, and the 1:5 (algae/sludge) culture showed the best settleability. Furthermore, 16S rDNA gene analysis showed that the bacterial communities were varying with different algae and sludge inoculation ratios and some specific bacteria were enriched during operation.

  11. Oleosin of subcellular lipid droplets evolved in green algae.

    PubMed

    Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L; Huang, Anthony H C

    2013-04-01

    In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants. PMID:23391579

  12. Aragonitic Pennsylvanian phylloid algae from New Mexico: The missing link

    SciTech Connect

    Kirkland, B.L.; Moore, C.H. Jr. ); Dickson, J.A.D. )

    1991-03-01

    Remarkably well-preserved codiacean algae (Eugonophyllum and Anchicodium) retaining original aragonite are present in the Virgilian Holder Formation, Sacramento Mountains, south-central New Mexico. The algae are preserved in a 20-cm-thick packstone between two thick (> 5m) shale beds. Aragonite is preserved as a felt-like mesh of needles in the algal skeletons, in the shell fragments of molluscs, in the walls of sponges, and in botryoidal and isopachous marine cements. The aragonite is confirmed by X-ray diffraction, by visual inspection of pristine aragonite needles with SEM, and by a high content of Sr as revealed by microprobe analysis. The average Sr content of the algae (9,091 ppm, n = 21) is comparable to modern codiaceans. Preservation of internal structure in Eugonophyllum was previously unknown. The medullary (interior) region of the Eugonophyllum thallus is composed of an aragonite felt punctuated by small (20 {mu}m diameter), parallel utricles. As in modern codiaceans, the utricles in the cortical (exterior) region of the thallus increase in diameter and their bulbous tips coalesce to form the outer cortex of the plant. This occurrence provides a key piece of evidence in support of hypotheses concerning the nature and origin of phylloid algal bioherms. Because the internal structure of most fossil phylloid algae is replaced by sparry mosaic calcite, taxonomic classification has been difficult even at the fundamental level of division (phylum). The authors discovery confirms that at least some ancient phylloid algae resembled the modern green algae Halimeda or Udotea, and lends credibility to the suggestion that ancient phylloid algal mounds are analogous to modern Halimeda mounds of the South Pacific.

  13. [Sedimentary Phosphorus Forms Under Disturbances and Algae in Taihu Lake].

    PubMed

    Chen, Jun; Li, Da-peng; Zhu, Pei-ying; Huang, Yong; Wang, Ren

    2015-12-01

    Sedimentary phosphorus forms were investigated to clarify the release of sedimentary phosphorus forms under the repeated disturbance with the addition of algae at different initial concentrations. The sediments and overlying water were taken from the Meiliang Bay in Taihu Lake. The results showed that the concentrations of NH₄ Cl-P and Res-P decreased, while the content of Fe/Al-P and Ca-P increased without disturbance. In addition, the Ca-P increased with the increase of the initial concentration of algae and the net increase of Ca-P increased by 48% (30 µg · L⁻¹), 66% (60 µg · L⁻¹), 74% (120 µg · L⁻¹), respectively. However, under the disturbance, the NH₄Cl-P and Res-P were significantly reduced, the Fe/Al-P increased significantly. The percentage of Fe/Al-P to Tot-P was up to 66. 2% (average of the 3 experiments with the addition of algae of 30 µg · L⁻¹, 60 µg · L⁻¹ and 120 µg L-¹), it was higher than the value (53.%, average of the 3 experiments) without the disturbance. Moreover, under the disturbance, the percentage of Ca-P to Tot-P was 24.1% (average of the 3 experiments with the addition of algae of 30 µg · L⁻¹, 60 µg⁻¹ and 120 µg · L⁻¹) and it was slightly lower than that (33.0%, average of the 3 experiments) without the disturbance. It is suggested that the coexistence of disturbance and algae facilitated the formation of Fe/Al-P, but the algae accelerated the formation of Ca-P without disturbance.

  14. Oleosin of subcellular lipid droplets evolved in green algae.

    PubMed

    Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L; Huang, Anthony H C

    2013-04-01

    In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants.

  15. Smallest algae thrive as the Arctic Ocean freshens.

    PubMed

    Li, William K W; McLaughlin, Fiona A; Lovejoy, Connie; Carmack, Eddy C

    2009-10-23

    As climate changes and the upper Arctic Ocean receives more heat and fresh water, it becomes more difficult for mixing processes to deliver nutrients from depth to the surface for phytoplankton growth. Competitive advantage will presumably accrue to small cells because they are more effective in acquiring nutrients and less susceptible to gravitational settling than large cells. Since 2004, we have discerned an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae. If this trend toward a community of smaller cells is sustained, it may lead to reduced biological production at higher trophic levels. PMID:19900890

  16. Algae Biofuels Co-Location Assessment Tool for Canada

    2011-11-29

    The Algae Biofuels Co-Location Assessment Tool for Canada uses chemical stoichiometry to estimate Nitrogen, Phosphorous, and Carbon atom availability from waste water and carbon dioxide emissions streams, and requirements for those same elements to produce a unit of algae. This information is then combined to find limiting nutrient information and estimate potential productivity associated with waste water and carbon dioxide sources. Output is visualized in terms of distributions or spatial locations. Distances are calculated betweenmore » points of interest in the model using the great circle distance equation, and the smallest distances found by an exhaustive search and sort algorithm.« less

  17. Algae Biofuels Co-Location Assessment Tool for Canada

    SciTech Connect

    2011-11-29

    The Algae Biofuels Co-Location Assessment Tool for Canada uses chemical stoichiometry to estimate Nitrogen, Phosphorous, and Carbon atom availability from waste water and carbon dioxide emissions streams, and requirements for those same elements to produce a unit of algae. This information is then combined to find limiting nutrient information and estimate potential productivity associated with waste water and carbon dioxide sources. Output is visualized in terms of distributions or spatial locations. Distances are calculated between points of interest in the model using the great circle distance equation, and the smallest distances found by an exhaustive search and sort algorithm.

  18. ECOLOGY: California Algae May Be Feared European Species.

    PubMed

    Kaiser, J

    2000-07-14

    A volleyball-court-sized patch of bright green algae in a San Diego lagoon has set off alarm bells among ecologists and officials. Scientists strongly suspect that the algae, Caulerpa taxifolia, is the same fast-growing, non-native clone that has swept over the northwestern Mediterranean sea floor in the past decade with devastating ecological consequences. A consortium of agencies and private groups has cordoned off the lagoon and is laying plans to poison the seaweed, marking the first major U.S. attempt to stop an incipient marine species invasion. PMID:17750394

  19. Algae as promising organisms for environment and health

    PubMed Central

    2011-01-01

    Algae, like other plants, produce a variety of remarkable compounds collectively referred to as secondary metabolites. They are synthesized by these organisms at the end of the growth phase and/or due to metabolic alterations induced by environmental stress conditions. Carotenoids, phenolic compounds, phycobiliprotein pigments, polysaccharides and unsaturated fatty acids are same of the algal natural products, which were reported to have variable biological activities, including antioxidant activity, anticancer activity, antimicroabial activity against bacteria-virus-algae-fungi, organic fertilizer and bioremediation potentials. PMID:21862867

  20. Value of crops: Quantity, quality and cost price. [algae as a nutritional supplement

    NASA Technical Reports Server (NTRS)

    Meyer, C.

    1979-01-01

    Possibilities of using algae as a nutritional supplement are examined. The nutritional value and protein content of spirulines of blue algae are discussed. A cost analysis of growing them artificially is presented.

  1. Where Have All the Algae Gone, or, How Many Kingdoms Are There?

    ERIC Educational Resources Information Center

    Blackwell, Will H.; Powell, Martha J.

    1995-01-01

    Examined 10 introductory college-level, general biology survey textbooks for the coverage of algae to assess the efficacy of coverage. Describes a proposal of seven kingdoms and discusses the disposition of algae among five of these kingdoms. Contends that textbooks should highlight the concept of algae across the five kingdoms. Contains 59…

  2. MONITORING CHLOROPHYLL-A AS A MEASURE OF ALGAE IN LAKE WATER

    EPA Science Inventory

    Algae are an important quality component in water bodies. They are photosynthesizing organisms and are the foundation of most aquatic food webs; however, some algae (e.g. blue-green algae) can produce algal toxins. The presence of algal toxins in water bodies has important ...

  3. Biodegradation of phenols by the alga Ochromonas danica.

    PubMed Central

    Semple, K T; Cain, R B

    1996-01-01

    The eukaryotic alga Ochromonas danica, a nutritionally versatile, mixotrophic chrysophyte, grew on phenol as the sole carbon source in axenic culture and removed the phenol carbon from the growth medium. Respirometric studies confirmed that the enzymes involved in phenol catabolism were inducible and that the alga oxidized phenol; the amount of oxygen consumed per mole of oxidized substrate was approximately 65% of the theoretical value. [U-14C]phenol was completely mineralized, with 65% of the 14C label appearing as 14CO2, approximately 15% remaining in the aqueous medium, and the rest accounted for in the biomass. Analysis of the biomass showed that 14C label had been incorporated into the protein, nucleic acid, and lipid fractions; phenol carbon is thus unequivocally assimilated by the alga. Phenol-grown cultures of O. danica converted phenols to the corresponding catechols, which were further metabolized by the meta-cleavage pathway. This surprising result was rigorously confirmed by taking the working stock culture through a variety of procedures to check that it was axenic and repeating the experiments with algal extracts. This is, as far as is known, the first definitive identification of the meta-cleavage pathway for aromatic ring degradation in a eukaryotic alga, though its incidence in other eukaryotes has been (infrequently) suggested. PMID:8919787

  4. Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.

    PubMed

    Dembitsky, V M; Shkrob, I; Rozentsvet, O A

    2000-08-01

    Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%).

  5. Optimization of light use efficiency for biofuel production in algae.

    PubMed

    Simionato, Diana; Basso, Stefania; Giacometti, Giorgio M; Morosinotto, Tomas

    2013-12-01

    A major challenge for next decades is development of competitive renewable energy sources, highly needed to compensate fossil fuels reserves and reduce greenhouse gas emissions. Among different possibilities, which are currently under investigation, there is the exploitation of unicellular algae for production of biofuels and biodiesel in particular. Some algae species have the ability of accumulating large amount of lipids within their cells which can be exploited as feedstock for the production of biodiesel. Strong research efforts are however still needed to fulfill this potential and optimize cultivation systems and biomass harvesting. Light provides the energy supporting algae growth and available radiation must be exploited with the highest possible efficiency to optimize productivity and make microalgae large scale cultivation energetically and economically sustainable. Investigation of the molecular bases influencing light use efficiency is thus seminal for the success of this biotechnology. In this work factors influencing light use efficiency in algal biomass production are reviewed, focusing on how algae genetic engineering and control of light environment within photobioreactors can improve the productivity of large scale cultivation systems.

  6. A simple classification of the volvocine algae by formal languages.

    PubMed

    Yoshida, Hiroshi; Yokomori, Takashi; Suyama, Akira

    2005-11-01

    There are several explanations of why certain primitive multicellular organisms aggregate in particular forms and why their constituent cells cooperate with one another to a particular degree. Utilizing the framework of formal language theory, we have derived one possible simple classification of the volvocine algae-one of the primitive multicells-for some forms of aggregation and some degrees of cooperation among cells. The volvocine algae range from the unicellular Chlamydomonas to the multicellular Volvox globator, which has thousands of cells. The classification we use in this paper is based on the complexity of Parikh sets of families on Chomsky hierarchy in formal language theory. We show that an alga with almost no space closed to the environment, e.g., Gonium pectorale, can be characterized by PsFIN, one with a closed space and no cooperation, e.g., Eudorina elegans, by PsCF, and one with a closed space and cooperation, e.g., Volvox globator, by PslambdauSC. This classification should provide new insights into the necessity for specific forms and degrees of cooperation in the volvocine algae. PMID:16005503

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

    PubMed

    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.

  8. Effect of sonication frequency on the disruption of algae.

    PubMed

    Kurokawa, Masaki; King, Patrick M; Wu, Xiaoge; Joyce, Eadaoin M; Mason, Timothy J; Yamamoto, Ken

    2016-07-01

    In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption. PMID:26964936

  9. Settlement of marine periphytic algae in a tropical estuary

    NASA Astrophysics Data System (ADS)

    Nayar, S.; Goh, B. P. L.; Chou, L. M.

    2005-08-01

    This note describes settlement studies of marine periphytic algae on glass substrata in a tropical estuary in Singapore. The rates of production in terms of 14C radiotracer uptake, biomass in terms of chlorophyll a, community structure and cell abundance were measured from the settled periphytic algae at various depths in the water column and compared with the prevailing hydrographical conditions. Relatively higher periphytic algal settlement was observed at 1 m depth, even though it was not statistically different from other depths. Diatoms such as Skeletonema costatum and Thalassiosira rotula dominated the assemblage, together with the marine cyanobacteria Synechococcus sp. The three settlement parameters viz., periphytic algal production, chlorophyll a and cell counts showed significant differences between the days of settlement, with no significant differences observed for different depths. The periphytic algal community in this study comprised 30 microalgal species, dominated by diatoms (78%), followed by cyanobacteria (19% - primarily Synechococcus sp.), green flagellates (1%), dinoflagellates (1%) and other forms accounting for the remaining 1% of the total cell counts. Correlation studies and principal component analysis (PCA) revealed significant influence of silicate concentrations in the water column with the settlement of periphytic algae in this estuary. Though photoinhibited at the surface, photosynthetically available radiation did not seem to influence the overall settlement of periphytic algae. Diatoms and Synechococcus in the periphytic algal community were influenced by water temperature, PAR, pH and dissolved oxygen as seen in the PCA plots.

  10. Survey of Hydrogenase Activity in Algae: Final Report

    SciTech Connect

    Brand, J. J.

    1982-04-01

    The capacity for hydrogen gas production was examined in nearly 100 strains of Eukaryotic algae. Each strain was assessed for rate of H2 production in darkness, at compensating light intensity and at saturating Tight intensity. Maximum H2 yield on illumination and sensitivity to molecular oxygen were also measured.

  11. MicroRNAs in a multicellular green alga Volvox carteri.

    PubMed

    Li, Jingrui; Wu, Yang; Qi, Yijun

    2014-01-01

    microRNAs (miRNAs) have emerged as key components in the eukaryotic gene regulatory network. We and others have previously identified many miRNAs in a unicellular green alga, Chlamydomonas reinhardtii. To investigate whether miRNA-mediated gene regulation is a general mechanism in green algae and how miRNAs have been evolved in the green algal lineage, we examined small RNAs in Volvox carteri, a multicellular species in the same family with Chlamydomonas reinhardtii. We identified 174 miRNAs in Volvox, with many of them being highly enriched in gonidia or somatic cells. The targets of the miRNAs were predicted and many of them were subjected to miRNA-mediated cleavage in vivo, suggesting that miRNAs play regulatory roles in the biology of green algae. Our catalog of miRNAs and their targets provides a resource for further studies on the evolution, biological functions, and genomic properties of miRNAs in green algae. PMID:24369344

  12. Intracellular invasion of green algae in a salamander host

    PubMed Central

    Kerney, Ryan; Kim, Eunsoo; Hangarter, Roger P.; Heiss, Aaron A.; Bishop, Cory D.; Hall, Brian K.

    2011-01-01

    The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell–cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures. PMID:21464324

  13. Decreased abundance of crustose coralline algae due to ocean acidification

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Andersson, Andreas J; Jokiel, Paul L.; Rodgers, Ku'ulei S.; Mackenzie, Fred T.

    2008-01-01

    Owing to anthropogenic emissions, atmospheric concentrations of carbon dioxide could almost double between 2006 and 2100 according to business-as-usual carbon dioxide emission scenarios1. Because the ocean absorbs carbon dioxide from the atmosphere2, 3, 4, increasing atmospheric carbon dioxide concentrations will lead to increasing dissolved inorganic carbon and carbon dioxide in surface ocean waters, and hence acidification and lower carbonate saturation states2, 5. As a consequence, it has been suggested that marine calcifying organisms, for example corals, coralline algae, molluscs and foraminifera, will have difficulties producing their skeletons and shells at current rates6, 7, with potentially severe implications for marine ecosystems, including coral reefs6, 8, 9, 10, 11. Here we report a seven-week experiment exploring the effects of ocean acidification on crustose coralline algae, a cosmopolitan group of calcifying algae that is ecologically important in most shallow-water habitats12, 13, 14. Six outdoor mesocosms were continuously supplied with sea water from the adjacent reef and manipulated to simulate conditions of either ambient or elevated seawater carbon dioxide concentrations. The recruitment rate and growth of crustose coralline algae were severely inhibited in the elevated carbon dioxide mesocosms. Our findings suggest that ocean acidification due to human activities could cause significant change to benthic community structure in shallow-warm-water carbonate ecosystems.

  14. NADPH oxidases in Eukaryotes: red algae provide new hints!

    PubMed

    Hervé, Cécile; Tonon, Thierry; Collén, Jonas; Corre, Erwan; Boyen, Catherine

    2006-03-01

    The red macro-alga Chondrus crispus is known to produce superoxide radicals in response to cell-free extracts of its green algal pathogenic endophyte Acrochaete operculata. So far, no enzymes involved in this metabolism have been isolated from red algae. We report here the isolation of a gene encoding a homologue of the respiratory burst oxidase gp91(phox) in C. crispus, named Ccrboh. This single copy gene encodes a polypeptide of 825 amino acids. Search performed in available genome and EST algal databases identified sequences showing common features of NADPH oxidases in other algae such as the red unicellular Cyanidioschyzon merolae, the economically valuable red macro-alga Porphyra yezoensis and the two diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. Domain organization and phylogenetic relationships with plant, animal, fungal and algal NADPH oxidase homologues were analyzed. Transcription analysis of the C. crispus gene revealed that it was over-transcribed during infection of C. crispus gametophyte by the endophyte A. operculata, and after incubation in presence of atrazine, methyl jasmonate and hydroxyperoxides derived from C20 polyunsaturated fatty acids (PUFAs). These results also illustrate the interest of exploring the red algal lineage for gaining insight into the deep evolution of NADPH oxidases in Eukaryotes.

  15. Controlled artificial upwelling in a fjord to combat toxic algae

    NASA Astrophysics Data System (ADS)

    McClimans, T. A.; Hansen, A. H.; Fredheim, A.; Lien, E.; Reitan, K. I.

    2003-04-01

    During the summer, primary production in the surface layers of some fjords depletes the nutrients to the degree that some arts of toxic algae dominate the flora. We describe an experiment employing a bubble curtain to lift significant amounts of nutrient-rich seawater to the light zone and provide an environment in which useful algae can survive. The motivation for the experiment is to provide a local region in which mussels can be cleansed from the effects of toxic algae. Three 100-m long, perforated pipes were suspended at 40 m depth in the Arnafjord, a side arm of the Sognefjord. Large amounts of compressed air were supplied during a period of three weeks. The deeper water mixed with the surface water and flowed from the mixing region at 5 to 15 m depth. Within a few days, the mixture of nutrient-rich water covered most of the inner portion of Arnafjord. Within 10 days, the plankton samples showed that the artificial upwelling produced the desired type of algae and excluded the toxic blooms that were occurring outside the manipulated fjord arm. The project (DETOX) is supported by the Norwegian ministries of Fisheries, Agriculture and Public Administration.

  16. Effect of sonication frequency on the disruption of algae.

    PubMed

    Kurokawa, Masaki; King, Patrick M; Wu, Xiaoge; Joyce, Eadaoin M; Mason, Timothy J; Yamamoto, Ken

    2016-07-01

    In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption.

  17. Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.

    PubMed

    Dembitsky, V M; Shkrob, I; Rozentsvet, O A

    2000-08-01

    Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%). PMID:11014298

  18. Antibiotic activity of lectins from marine algae against marine vibrios.

    PubMed

    Liao, W-R; Lin, J-Y; Shieh, W-Y; Jeng, W-L; Huang, R

    2003-07-01

    Saline and aqueous ethanol extracts of marine algae and the lectins from two red algal species were assayed for their antibiotic activity against marine vibrios. Experimental studies were also carried out on the influence of environmental factors on such activity, using batch cultures. The results indicated that many of the saline extracts of the algal species were active and that the activity was selective against those vibrios assayed. The algal extracts were active against Vibrio pelagius and the fish pathogen V. vulnificus, but inactive against V. neresis. Algal lectins from Eucheuma serra (ESA) and Galaxaura marginata (GMA) strongly inhibited V. vulnificus but were inactive against the other two vibrios. The antibacterial activity of algal extracts was inhibited by pretreatment with various sugars and glycoprotein. Extracts of the two red algae, E. serra and Pterocladia capillacea, in saline and aqueous ethanol, inhibited markedly the growth rate of V. vulnificus at very low concentrations. Culture results indicated that metabolites active against V. vulnificus were invariably produced in P. capillacea over a wide range of temperature, light intensity, and nutritional conditions. Enhanced antibacterial activity occurred when P. capillacea was grown under higher irradiance, severe nutrient stress and moderate temperature (20 degrees C), reflecting the specific antibiotic characteristics of this alga. The strong antibiotic activity of lectins towards fish pathogenic bacteria reveals one of the important roles played by algal lectins, as well as the potential high economic value of those marine algae assayed for aquaculture and for biomedical purposes. PMID:12884128

  19. Ecological assessments with algae: a review and synthesis.

    PubMed

    Stevenson, Jan

    2014-06-01

    Algae have been used for a century in environmental assessments of water bodies and are now used in countries around the world. This review synthesizes recent advances in the field around a framework for environmental assessment and management that can guide design of assessments, applications of phycology in assessments, and refinements of those applications to better support management decisions. Algae are critical parts of aquatic ecosystems that power food webs and biogeochemical cycling. Algae are also major sources of problems that threaten many ecosystems goods and services when abundances of nuisance and toxic taxa are high. Thus, algae can be used to indicate ecosystem goods and services, which complements how algal indicators are also used to assess levels of contaminants and habitat alterations (stressors). Understanding environmental managers' use of algal ecology, taxonomy, and physiology can guide our research and improve its application. Environmental assessments involve characterizing ecological condition and diagnosing causes and threats to ecosystems goods and services. Recent advances in characterizing condition include site-specific models that account for natural variability among habitats to better estimate effects of humans. Relationships between algal assemblages and stressors caused by humans help diagnose stressors and establish targets for protection and restoration. Many algal responses to stressors have thresholds that are particularly important for developing stakeholder consensus for stressor management targets. Future research on the regional-scale resilience of algal assemblages, the ecosystem goods and services they provide, and methods for monitoring and forecasting change will improve water resource management.

  20. Switchable photosystem-II designer algae for photobiological hydrogen production

    DOEpatents

    Lee, James Weifu

    2010-01-05

    A switchable photosystem-II designer algae for photobiological hydrogen production. The designer transgenic algae includes at least two transgenes for enhanced photobiological H.sub.2 production wherein a first transgene serves as a genetic switch that can controls photosystem II (PSII) oxygen evolution and a second transgene encodes for creation of free proton channels in the algal photosynthetic membrane. In one embodiment, the algae includes a DNA construct having polymerase chain reaction forward primer (302), a inducible promoter (304), a PSII-iRNA sequence (306), a terminator (308), and a PCR reverse primer (310). In other embodiments, the PSII-iRNA sequence (306) is replaced with a CF.sub.1-iRNA sequence (312), a streptomycin-production gene (314), a targeting sequence (316) followed by a proton-channel producing gene (318), or a PSII-producing gene (320). In one embodiment, a photo-bioreactor and gas-product separation and utilization system produce photobiological H.sub.2 from the switchable PSII designer alga.