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1Author    Siegrid Schoch2, Hugo Scheer3, JeromeA. Schiff2, W. Olfhart, R. Ü D Ig Er3, H. Arold, W. SiegelmRequires cookie*
 Title    Pyropheophytin a Accompanies Pheophytin a in Darkened Light Grown Cells of Euglena1  
 Abstract    Chromatography Light-grown non-dividing cells of Euglena gracilis Klebs var. bacillaris Cori form pheophytin a like pigments from chlorophyll a without loss of viability when they are allowed to incubate in darkness without shaking. This is accompanied by the loss of long-wavelength components in the red absorption band of intact cells. After extraction of these cells with acetone, transfer of the pigments to ether and treatment of the ether solution with dilute acid, two pigments can be separated by high performance liquid chromatography on reverse phase silica gel (RP-8) using methanol: water = 95:5 (v/v) as the eluting solvent: In addition to pheophytin a, the eluate contains an unknown pigment. With increasing times of incubation of the cells in darkness, the proportion of pheophytin a decreases and the proportion of the unknown increases suggesting, that the unknown is formed from pheophytin a. This pigment has been identified as pyropheophytin a. It has the same absorption spectrum as pyropheophytin a (prepared by pyridine pyrolysis of pheophytin a) and contains phytol as the longchain esterifying alcohol. On conversion to the methyl ester, the resulting methyl phorbide is identical with authentic pyromethylpheophorbide a by tic, hplc, absorption, absorption difference and mass spectros­ copy. This is the first report of pyropheophytin a or any pyrochlorophyll derivative from plants or oxygenic plant-like microorganisms where it may serve as an intermediate in chlorophyll degradation. 
  Reference    Z. Naturforsch. 36c, 827—833 (1981); received June 191981 
  Published    1981 
  Keywords    Euglena, Chlorophyll Degradation, Pyropheophytin, Photosynthesis, High Performance 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0827.pdf 
 Identifier    ZNC-1981-36c-0827 
 Volume    36 
2Author    Wolfram Lork, Til Kreuels, Wolfgang Martin, Klaus BrinkmannRequires cookie*
 Title    System Analysis of the Circadian Rhythm of Euglena gracilis, I. Linearities and Non-Linearities in the Response to Temperature Signals  
 Abstract    The approach of control theory is used to describe the structure of the circadian system of Euglena gracilis. As a first step we discriminate linear and non linear properties of the dynamics. The cellular motility as measured via long time records of sedimentation parameters in cultures is defined as the system output; sinusoidal temperature signals are used as input. By means of non stationary signal processing procedures we estimate gain and phase of the output signal. The problem of defining an appropiate gain of a cell suspension with an undefinite number of cells is solved by using the superimposition of two different input signals and by keeping one of them fixed as a reference signal. Linear properties are shown with a linear frequency transfer and with the validity of the superposition principle at least within distinct regions of amplitude and frequency. Non linear properties are the signal distortion, the restriction of linear amplification to a distinct range of input temperature and the ambiguity of phase coupling near the circadian eigenfrequency. The apparent lack of a limit of entrainment -an unexpected linear property — is explained by the masking effect of thermokinesis. A model is proposed describing the simultaneous control of motility by thermokinesis and the circadian system. On the base of that model further experiments are outlined. 
  Reference    Z. Naturforsch. 37c, 1240—1252 (1982); received June 15 1982 
  Published    1982 
  Keywords    Circadian Rhythm, Euglena, Motility, Oscillator, Temperature 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1240.pdf 
 Identifier    ZNC-1982-37c-1240 
 Volume    37 
3Author    GeorgH. Schmid, Pierre ThibaultRequires cookie*
 Title    Studies on the S-State Distribution in Euglena gracilis  
 Abstract    When Euglena gracilis is dark adapted for 10 min or more, oxygen evolution as the conse­ quence of short (5 usee) saturating light flashes does not show the picture of a damped oscillation with a periodicity o f 4, as known from the literature. The overall picture of this flash pattern is given by the fact that 0 2-evolution in the First two flashes is practically zero and rises from there onward in a continuous manner to the steady state with barely any visible oscillation at all. However, a second flash sequence fired one to two minutes after this first sequence induces an oxygen evolution pattern which is barely distinguishable from the well known usual Chlorella vulgaris pattern. The phenomenon is not influenced by changes in the oxygen tension nor do additions of chemicals like CCCP, sodium azide, or reducing agents like hydroxylamine or hydrogen peroxide substantially alter the described behavior. Deactivation experiments give the overall impression that the deactivation of the S-states is slower than with Chlorella. Hydroxylamine strongly accelerates the deactivation. The analysis of the S-state distribution in a four and five state Kok-model suggests that dark adapted Euglena is in a more reduced condition than dark adapted Chlorella. It looks as if dark adapted Euglena were in a condition which would correspond to 60 percent S_|, 30 percent S0 and 10 percent S). The experimental flash sequence of such dark adapted cells fits best a synthetic sequence when the misses are in the region of 2 0 -2 5 percent, with double hitting playing practically no role at all (the first two flashes are zero!). The impression that dark adapted Euglena starts its oxygen evolution from a more reduced state is strengthened by the analysis of room temperature fluorescence induction (Kautsky effect). It can be shown that the fluorescence induction curve o f Euglena corresponds to that of Chlorella cells provided the latter have been briefly treated with a strong reductant such as sodium dithionite. 
  Reference    Z. Naturforsch. 38c, 60—6 (1983); received September 1982 
  Published    1983 
  Keywords    Flash Yield, Oxygen, Euglena, Fluorescence Induction 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0060.pdf 
 Identifier    ZNC-1983-38c-0060 
 Volume    38 
4Author    Margarete Hoffmans-Hohn, W. Olfgang, M. Artin, Klaus BrinkmRequires cookie*
 Title    Multiple Periodicities in the Circadian System of Unicellular Algae  
 Abstract    Three periodicities in the circadian range are observed when m easuring circadian parameters of unicellular organisms in long running experim ents (m ore than 15 days). This is dem onstrated for different organisms (Chlamydomonas, Euglena, C hlorella) and different parameters (auto­ kinesis, extracellular pH, C 0 2-and 0 2-partial pressure). H aving excluded analytical and experimental artefacts {i.e. filter leakage and subpopulation effects), the m ultiple periodicities have to be interpreted in a physiological m odel. The three p eriod icities always exhibit two common features: The locations o f the side peaks are sym m etrical to the m iddle peak and their energy contribution is always the same. W e therefore favour the m odel o f m ultiplicative coupling between the circadian oscillator and a low frequency oscillator m odulating the am plitude o f the circadian rhythm. Since the low frequency rhythm is not correlated to any exogenously running periodicity o f the experim ental surroundings, it is considered as generated by an endogenous oscillator. This shows the existence o f different biological long tim e oscillators in one single cell and contradicts the so-called m aster-clock hypothesis stating that one cell has only one clock related oscillator. 
  Reference    Z. Naturforsch. 39c, 791—8 (1984); received D ecem ber 5 1983/M arch 17 1984 
  Published    1984 
  Keywords    Circadian Rhythm, pH-Rhythm, Chlamydomonas, Euglena, Chlorella 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0791.pdf 
 Identifier    ZNC-1984-39c-0791 
 Volume    39 
5Author    A. Aiach, U. Bodner, U. JohanningmRequires cookie*
 Title    A Herbicide Resistant Euglena Mutant Carrying a Ser to Thr Substitution at Position 265 in the D 1 Protein of Photosystem II  
 Abstract    A herbicide resistant Euglena mutant (M SI) has been obtained by adapting wild type cells to increasing concentrations o f D C M U (3-(3',4'-dichlorophenyl)-l ,1-dimethylurea). Lower re­ sistance levels towards D C M U and metribuzin were observed in MSI when compared with Euglena or C hlam ydom onas mutants with Ser 264 to Ala substitutions. RNA-sequence analysis identified a Ser to Thr change at position 265 (equivalent to position 264 in other organisms), thus making it possible to compare the influence o f amino acids Ser, Ala and Thr at identical positions on the inhibitory effect o f structurally different herbicides in the same species. 
  Reference    Z. Naturforsch. 47c, 245 (1992); received October 31 1991 
  Published    1992 
  Keywords    Herbicides, D 1-Protein, Point M utation, Resistance, Euglena 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0245.pdf 
 Identifier    ZNC-1992-47c-0245 
 Volume    47 
6Author    Jack Farineaua, DanielleM. Laval-, ArtinbRequires cookie*
 Title    Characteristics of Thermoluminescence Bands of Euglena Cells Belonging to 2 Lines Presenting Different Degrees of Diuron-Resistance  
 Abstract    We have analysed the thermoluminescence (TL) properties of two lines o f Euglena exhibit­ ing two degrees of resistance to diuron, by a factor of 100 (Z R 25) and 1000 (Z R 250) respectively, as compared to wild type line (Z). In addition, the two ZR lines developped an identical resistance to atrazine since the I50 for this herbicide in each line was 75 times larger than in wild type. Special TL characteristics were evidenced in the two lines. Bands after 2 flashes (or more) showed a shift o f the peak maximum towards low temperature, the shift being the largest in the most DCM U-resistant cells. Similar results were obtained with isolated thylakoids, except that the TL bands appeared at a temperature higher than in corresponding cells. Oscillations in the amplitude of the bands in a flash sequence were largely damped in cells (and thylakoids), particularly in the most DCM U-resistant lines. The results are interpreted as indicating accumulation of Q a "Qb after flashes due to a decrease of the equilibrium constant for the reaction Q a ~Qb ^ QaQb~ accompanying the D CM U resistance. 
  Reference    Z. Naturforsch. 50c, 86—9 (1995); received October 12/November 21 1994 
  Published    1995 
  Keywords    Diuron, Euglena, Herbicide-Resistance, Photosystem II, Thermoluminescence 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0086.pdf 
 Identifier    ZNC-1995-50c-0086 
 Volume    50