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1Author    BlahoslavM. Aršálek, Renata RojíčkováRequires cookie*
 Title    Stress Factors Enhancing Production of Algal Exudates: a Potential Self-Protective Mechanism?  
 Abstract    Algae are known to produce extracellular organic substances under optimum conditions and increase their production under stress. The changes in amount and composition of extra­ cellular carbohydrates and proteins of three green algae Scenedesmus quadricauda, Chlorella kessleri and Raphidocelis subcapitata (known as Selenastrum capricornutum) were studied after a 5-days' cultivation under the influence of different types o f stress factors (osm otic, organic, and heavy metal stressors). NaCl enhanced the quantity of carbohydrates more than proteins. A higher increase o f proteins than carbohydrates was observed after addition of 3,5-dichlorophenol, glyphosate and cadmium chloride to algal cultures. The production of dissolved organic matter differs from species to species, with the age of a culture and the type of stressor. 
  Reference    Z. Naturforsch. 51c, 646 (1996); received May 28/June 25. 1996 
  Published    1996 
  Keywords    Algae, Extracellular Products, Proteins, Carbohydrates 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0646.pdf 
 Identifier    ZNC-1996-51c-0646 
 Volume    51 
2Author    Henrik Laasch, Klaus Pfister, Wolfgang UrbachRequires cookie*
 Title    Comparative Binding of Photosystem II — Herbicides to Isolated Thylakoid Membranes and Intact Green Algae  
 Abstract    The binding of the photosystem II herbicides diuron (DCM U), atrazine (s-triazine), ioxynil and dinoseb (substituted phenols) to isolated spinach thylakoids was saturated in less than 2 min in the dark. In intact cells of the green alga Ankistrodesmus b. it took 10 to 20 min to reach the binding equilibrium. Binding affinity of diuron, atrazine, dinoseb, measured as equilibrium binding constants, was found to be comparable in isolated thylakoids and intact algal cells. For ioxynil, reduced binding affinity was observed in algae. The concentration of binding sites in thylakoids and intact cells was determined to be 300-500 chl/inhibitor binding site, suggesting a 1:1 stoichiometry between bound herbicide and electron transport chains. In intact cells only the phenol herbicides ioxynil and dinoseb showed increased concentrations of binding sites. Strong correlation of herbicide binding and inhibition o f electron transport was found for diuron in isolated thylakoids and intact cells. In thylakoids this is valid also for atrazine and dinoseb. For ioxynil a difference between the amount of binding and inhibition was found. This correlation o f herbicide binding and inhibition proves that binding specifically occurs at the inhibition site at photosystem H. In addition to the specific binding, for all four herbicides studied, (except for ioxynil in thylakoids) unspecific binding was observed in thylakoids as well as in algae, which was not related to inhibition. 
  Reference    Z. Naturforsch. 36c, 1041—1049 (1981); received July 13 1981 
  Published    1981 
  Keywords    Herbicides, Herbicide Binding, Photosynthesis, Thylakoids, Algae 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-1041.pdf 
 Identifier    ZNC-1981-36c-1041 
 Volume    36 
3Author    SeymourSteven Brody, Lisbeth StelzigRequires cookie*
 Title    Effect of Pressure on the Absorption Spectra of Phycobiliprotein and Porphyridium cruentum  
 Abstract    Changes in the absorption spectra o f P. cruentum and phycobiliprotein are observed as a function o f hydrostatic pressure. With phycobiliprotein both in solution and in algae, increasing hydrostatic pressure results in bathochrom ic shifts o f the absorption m axim a. In addition, there is a splitting o f the absorption band o f phycoerythrin. When P. cruentum is subjected to 250 bars there are increases in absorption by chlorophyll (at 700 and 698 nm), phycocyanin (at 640 nm) and phycoerythrin (at 580 and 550 nm). W hen a cell free solution o f phycobiliprotein is subjected to 300 bars there are increases in absorption by phycoerythrin (at 570 and 550 nm) and phycocyanin (at 634 nm). 
  Reference    Z. Naturforsch. 38c, 458—460 (1983); received January 21 1983 
  Published    1983 
  Keywords    Pressure, Phycobiliprotein, Algae, Pressure Induced Change in Absorption Spectra 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0458.pdf 
 Identifier    ZNC-1983-38c-0458 
 Volume    38 
4Author    BlahoslavM. Aršálek, Helena Zahradníčková, MarieH. RonkováRequires cookie*
 Title    Extracellular Production of Abscisic Acid by Soil Algae under Salt, Acid or Drought Stress  
 Abstract    The com m on soil green algae Chlorella vulgaris and Stichococcus hacillaris increase extra­ cellular abscisic acid (A BA) production under salt, acid or drought stress 5 -1 0 times. Produc­ tion o f A BA also increases from young to senescent cultures 2 -3 times. The relationship between age o f cultures and reaction to stress factors was found. Extra­ cellular A BA levels are 1 -2 times higher than cellular ones. Possible influence o f ABA to soil microbial associations, growth o f plants and soil fauna is discussed from an ecological point o f view. 
  Reference    Z. Naturforsch. 47c, 701 (1992); received June 10/July 21 1992 
  Published    1992 
  Keywords    Algae, Abscisic Acid, Extracellular Production, Stress Factors 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0701.pdf 
 Identifier    ZNC-1992-47c-0701 
 Volume    47 
5Author    Gerhard Sandmann, Karl-Josef Kunert, Peter BögerRequires cookie*
 Title    Biological Systems to Assay Herbicidal Bleaching  
 Abstract    Two strains of Scenedesmus acutus were found useful to study the influence of bleaching agents on either the greening process or the fully pigmented algal cell during growth. Both physiological conditions exhibit high sensitivity to bleaching herbicides. With this new assay, contrasting bleach­ ing effects with the same compound can be found allowing differentiation of the herbicidal action of bleaching agents which apparently is a multifunctional one. Furthermore, the I50 can be determined rather rapidly in a simple graphical method by a Dixon plot. A subsequent application of bleaching herbicides to cultures of the fungus Phycomyces blakesleeanus rules out a possible specific action of the compounds assayed on chlorophyll or photosynthetic redox carriers. This latter assay can show whether or not the herbicides synthesis as is the case with difunon or SAN 9789. 
  Reference    Z. Naturforsch. 34c, 1044—1046 (1979); received June 30 1979 
  Published    1979 
  Keywords    Bleaching Herbicides, Algae, Scenedesmus acutus, Wild-type and Mutant 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1044.pdf 
 Identifier    ZNC-1979-34c-1044 
 Volume    34 
6Author    Karl-JosefK. Unert, Peter BögerRequires cookie*
 Title    Influence of Bleaching Herbicides on Chlorophyll and Carotenoids  
 Abstract    Over 24 and 48 hour cultivation periods the influence of SAN 9789 (norflurazon), EMD-IT 5914 (difunon) and fluridone on growth, photosynthetic oxygen evolution and pigment content of the green alga Scenedesmus acutus was determined. Four effects were observed: a) Both carotenoid and chlorophyll formation were inhibited. b) Carotenoids were destroyed in the presence of air, but not nitrogen. The level of chlorophyll, however, did not change. c) ß-(and a-) carotene was markedly decreased in the presence of oxygen. d) Photosynthetic oxygen evolution was decreased with the disappearance of carotenoids. These effects, which are accompanied by reduced growth, are believed to represent primary herbicidal modes of action. The decrease of oxygen evolution is not due to a direct inhibition of photosynthetic electron transport by the herbicides applied. 
  Reference    Z. Naturforsch. 34c, 1047 (1979); received June 30 1979 
  Published    1979 
  Keywords    Bleaching Herbicides, Algae, Scenedesmus acutus, Carotenoids, Chlorophyll, Air/Nitrogen Gassing 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1047.pdf 
 Identifier    ZNC-1979-34c-1047 
 Volume    34 
7Author    Beate Klein, Hartmut FollmannRequires cookie*
 Title    Deoxyribonucleotide Biosynthesis in Green Algae. S Phase-Specific Thymidylate Kinase and Unspecific Nucleoside Diphosphate Kinase in Scenedesmus obliquus  
 Abstract    NDP kinase and thymidylate kinase are essential for DNA precursor formation in that they phosphorylate the products of de novo deoxyribonucleotide biosynthesis, deoxyribonucleoside 5'-diphosphates and thymidine 5'-monophosphate to the corresponding triphosphates which then serve as DNA polymerase substrates. The two enzymes have been measured in synchronous cultures of the green algae, S. obliquus. Thymidylate kinase exhibits an activity peak at the 11 —12th hour of the 24-hour cell cycle, coinciding with DNA synthesis. Enzyme activity is markedly stimulated in presence of fluorodeoxyuridine in the culture medium. This behaviour of dTMP kinase is very similar to that of three other S phase-specific peak enzymes previously analyzed in synchronous algae, viz. ribonucleotide reductase, thymidylate synthase, and dihydro-folate reductase. In contrast, NDP kinase exhibits high and constant activity through the entire cell cycle. The two kinases have been isolated from cell-free extracts, and separated from each other by chromatography on Blue Sepharose. The peak enzyme, dTMP kinase, has been purified to near homogeneity and its catalytic properties are described; the molecular weight is 56,000. NDP kinase activity is separable into two enzyme fractions, both of molecular weight 100,000 (or higher), which are unspecific with respect to ribonucleotide and deoxyribonucleotide substrates. Characterization and purification of the whole series of deoxyribonucleotide-synthesizing enzymes from one organism provides a basis for in vitro experiments towards reconstitution of an S phase-specific DNA precursor/DNA replication multien-».yme aggregate. 
  Reference    Z. Naturforsch. 43c, 377—385 (1988); received February 12/March 17 1988 
  Published    1988 
  Keywords    Algae, Cell Cycle, Deoxyribonucleotides, Nucleoside Diphosphate Kinase, Scenedesmus obliquus 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0377.pdf 
 Identifier    ZNC-1988-43c-0377 
 Volume    43 
8Author    M. Onika, Meyer, Christian WilhelmRequires cookie*
 Title    Reconstitution of Light-Harvesting Complexes from Chlorella fusca (Chlorophyceae) and Mantoniella squamata (Prasinophyceae)  
 Abstract    D edicated to Professor W. Rüdiger (München) on the occasion o f his 60 th anniversary Reconstitution experiments o f light-harvesting complexes were performed with the green alga Chlorella fusca and the chlorophyll c-eontaining prasinophyte M antoniella squamata using a modified method according to Plumley and Schmidt [Proc. N atl. Acad. Sei. U .S.A . 84, 146 -1 5 0 (1987)]. Changing the pigment supply quantitatively or qualitatively in the reconsti­ tution mixture hom ologous and heterologous reconstitutes were obtained. In contrast to higher plants, light-harvesting polypeptides from green algae are able to bind the chlorophylls as well as the xanthophylls in different stoichiometries. H eterologous reconstitutes o f M . squamata polypeptides give further evidence for a rather high flexibility o f pigment recog­ nition and binding. This is the first report o f successful reconstitution o f a chlorophyll c-binding protein. Contrary to chlorophyll c-less light-harvesting com plexes, the reconstitu­ tion o f M . squamata is strongly pH-controlled. In summary, the results give evidence for a high specificity o f porphyrin ring recognition and variability in xanthophyll binding capacity. Therefore, it is suggested that at least in algal light-harvesting proteins chlorophyll organiza­ tion may be determined by other mechanisms than xanthophyll binding. 
  Reference    Z. Naturforsch. 48c, 461 (1993); received December 12 1992/April 1 1993 
  Published    1993 
  Keywords    Algae, Reconstitution, Light-Harvesting Complex, Photosynthesis, Pigment-Protein Inter­ action 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0461.pdf 
 Identifier    ZNC-1993-48c-0461 
 Volume    48