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David R A Hill - One of the best experts on this subject based on the ideXlab platform.
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Chroomonas and other blue green cryptomonads
Journal of Phycology, 1991Co-Authors: David R A HillAbstract:Examination of four selected Chroomonas species indicates significant structural diversity within the genus. The concept of Chroomonas is reviewed, and new observations are presented on C. collegionis sp. nov. and C. coerulea (Geitler) Skuja. Examination of two other species, Chroomonas caudata Geitler and Chroomonas daucoides Conrad et Kufferath, forms the basis for the description of two new genera, Komma and Falcomonas. The generic taxonomy is based on the nature of the furrow-gullet system, periplast structure, and features of the plastidial complex. Certain nomenclatural treatments were required: Cyanomonas americana (Davis) Oltmanns is transferred to Chroomonas, C. rosenbergiae Huber-Pestalozzi is relegated to synonymy with C. coerulea (Geitler) Skuja, and the descriptions of Butcher's species C. mesostigmatica sp. nov. and C. collegionis sp. nov. are completed.
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Chroomonas AND OTHER BLUE‐GREEN CRYPTOMONADS
Journal of Phycology, 1991Co-Authors: David R A HillAbstract:Examination of four selected Chroomonas species indicates significant structural diversity within the genus. The concept of Chroomonas is reviewed, and new observations are presented on C. collegionis sp. nov. and C. coerulea (Geitler) Skuja. Examination of two other species, Chroomonas caudata Geitler and Chroomonas daucoides Conrad et Kufferath, forms the basis for the description of two new genera, Komma and Falcomonas. The generic taxonomy is based on the nature of the furrow-gullet system, periplast structure, and features of the plastidial complex. Certain nomenclatural treatments were required: Cyanomonas americana (Davis) Oltmanns is transferred to Chroomonas, C. rosenbergiae Huber-Pestalozzi is relegated to synonymy with C. coerulea (Geitler) Skuja, and the descriptions of Butcher's species C. mesostigmatica sp. nov. and C. collegionis sp. nov. are completed.
Roger G Hiller - One of the best experts on this subject based on the ideXlab platform.
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amino acid sequence of the β subunit of phycoerythrin from the cryptophyte algae Chroomonas cs 24
Biochimica et Biophysica Acta, 1992Co-Authors: Jasminka Godovaczimmermann, Margaret Sheil, Pamela M Wrench, Roger G HillerAbstract:Abstract The full amino acid sequence of the s-subunit of Chroomonas CS24 phycoerythrin has been determined by conventional Edman degradation and mass spectrometry. The sequence compromises 177 amino acids with a molecular mass of 18669 Da. It is 91.5% identical to the deduced amino acid sequence of Cryptomonas Φ s-phycoerythrin (Reith, M. and Douglas, S. (1990) Plant Mol. Biology 15, 585–592). The chromophores are bound by single thioether linkages. No evidence of microheterogeneity was found confirming that both s-subunits of the holoprotein are identical.
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A genomic clone encoding a cryptophyte phycoerythrin α-subunit: Evidence for three α-subunits and an N-terminal membrane transit sequence
FEBS Letters, 1990Co-Authors: J Jenkins, Roger G Hiller, J Speirs, J Godovac-zimmermannAbstract:Abstract A genomic library of Chroomonas (Cryptophyceae) DNA has been constructed in λEMBL4. Using a synthetic oligomer as a hybridization probe, a clone containing a phycoerythrin α-subunit has been obtained and sequenced. The principal α 1 and α 2 -subunits of the holoprotein have been partially sequenced by sequential Edman degradation and differ from the DNA derived sequence, providing evidence for at least 3 α-subunit genes. The nucleotide sequence of the α-subunit gene is GC rich and encodes an N-terminal extension which is putatively thylakoid-lumen directing.
Jorg Brock - One of the best experts on this subject based on the ideXlab platform.
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lectin binding in cryptomonas and Chroomonas cryptophyceae
Protoplasma, 2012Co-Authors: Erhard Rhiel, Jorg BrockAbstract:The cell envelopes of Cryptomonas and Chroomonas exhibited significant fluorescence using FITC-labelled concanavalin A and wheat germ agglutinin when the cells were fixed prior to lectin binding. The periplast became intensely labelled in Chroomonas whereas Cryptomonas showed fluorescing granula in its gullet/furrow region and on the cell surface. Lectin labelling followed by fixation showed only label of periplast remnants of lysed cells and of the flagella of Chroomonas. Isolated periplasts of Cryptomonas and Chroomonas were intensively labelled with both concanavalin A and wheat germ agglutinin. Glycostaining of gels, onto which total cell protein extracts were loaded, showed a glycoprotein of high molecular weight for Cryptomonas and Chroomonas and an additional glycoprotein for Cryptomonas species.
Masakatsu Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Chapter 12 Yellow-light sensing phototaxis in cryptomonad algae
Comprehensive Series in Photosciences, 2007Co-Authors: Masakatsu Watanabe, Mayumi ErataAbstract:Cryptomonad algae (cryptophyte algae), originated from a eukaryotic host cell and a eukaryotic endosymbiont by secondary endosymbiosis, are unicellular biflagellate, freshwater or marine, eukaryotic algae, unique among flagellate algae in having phycobiliproteins (Cr-phycoerythrin or Cr-phycocyanin) as photosynthetic accessory pigments. An eyespot is found only in some species (e.g. Chroomonas coerulea) although most of the cryptomonad species are phototactic. Cryptomonad phototaxis may be exclusively positive (Cryptomonas sp. CR-1, cryptomonas rostratiformis and Chroomonas nordstedtii) or exclusively negative (Chroomonas coerulea) or positive at low fluence rates and negative at higher fluence rates (Cryptomonas maculata) or diaphototactic, i.e. orienting perpendicular to the direction of the light beam (Cryptomonas sp. S2). Action spectroscopy for positive phototaxis in Cryptomonas sp. CR-1 led to the discovery of its very unique yellow-light sensing with an action peak in the yellow light region at ca. 560 nm, which was later confirmed in the action spectrum for positive phototaxis in cryptomonas rostratiformis and Chroomonas nordstedtii, together with a new action peak at 460 nm (the former showing also a UV peak at 280 nm), strongly suggesting that the photoreceptor mediating positive phototaxis is common among these species, and not phycobilins. Analyses using repeated pulses of stimulus light showed that light is sensed by the ventral side of Cryptomonas sp. CR-1 cells. The striking similarity of the action spectra for photoaccumulation and light-induced membrane depolarization in the ciliate Paramecium with that for the cryptomonad phototaxis seems to suggest considerable common nature of their unidentified photoreceptors. Analyses of phototactic responses of Cryptomonas sp. CR-1 cells to intermittent light stimuli with variable light durations and dark intervals revealed a striking dark interval dependence, suggesting also considerable similarity in the photoreceptor-signal transduction processes between cryptomonads and the green alga Chlamydomonas, in which retinal-binding protein(s) are supposed to work as the photoreceptor(s) for its green-light sensing phototaxis, suggesting that a dark interval dependence of phototaxis is theoretically expected on the basis of kinetic analyses of the photoreceptor current. The presence of Ca2+ is crucially needefor phototactic orientation and antagonized by K+ ions, consistently with other phototactic organisms such as Chlamydomonas, Euglena and Paramecium. The ecological significance of cryptomonad phototaxis is demonstrated, in general accordance with other algae, as the means for the cells to locate themselves in photosynthetically advantageous light habitats and to avoid harmful strong light or UV radiation both horizontally and vertically. The molecular identification of the photoreceptor pigment(s) as well as the understanding of the ecological and biochemical meanings of the UV-sensing in Cryptomonas is a challenging subject of future studies.
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ultrastructure and phototactic action spectra of two genera of cryptophyte flagellate algae cryptomonas and Chroomonas
Protoplasma, 1995Co-Authors: M Erata, Mamoru Kubota, T Takahashi, Isao Inouye, Masakatsu WatanabeAbstract:A comparative action spectroscopical study was made on phototaxis in two genera of cryptomonads (cryptophyte flagellate algae), namely,Cryptomonas (rostratiformis) andChroomonas (nordstedtii andcoeruled). The two genera differ in their characteristic phycobilin pigmentation and, among three species, onlyChroomonas coerulea possesses an eyespot. The two species with no eyespot,Cryptomonas rostratiformis andChroomonas nordstedtii, exhibited positive phototaxis, showing very similar action spectra characterized by a broad band in the region from 450 nm to 650 nm, with an action maximum at about 560 nm; these features are essentially the same as those observed previously forCryptomonas strain CR-1. InCryptomonas rostratiformis, a small peak was also found at 280 nm in the UV-B/C region.Chroomonas coerulea, with eyespot, did not exhibit distinct positive phototaxis in a wide spectral region at any given, even very low, light intensity, but exhibited negative phototaxis of spectral sensitivity maximal at 400–450 nm. These results indicate that the positive phototaxis ofCryptomonas (rostratiformis and CR-1) andChroomonas nordstedtii is mediated by the same, yet unidentified photoreceptor(s).Chroomonas nordstedtii, possessing no phycoerythrin absorbing at 545 nm, also exhibits positive phototaxis at ca. 560 nm, and this result disfavors the so far proposed possibility that the positive phototaxis of the cryptophytes may be mediated by phycobilin pigments. On the other hand, the spectral characteristics of negative phototaxis ofChroomonas coerulea can possibly be ascribed to the presence of an eyespot.
Kerstin Hoefemden - One of the best experts on this subject based on the ideXlab platform.
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revision of the genus Chroomonas hansgirg the benefits of dna containing specimens
Protist, 2018Co-Authors: Kerstin HoefemdenAbstract:For years the genus Chroomonas was defined as being a cryptophyte with rectangular periplast plates, with a gullet and with biliprotein types PC 630 or 645. In phylogenetic trees the genus proved to be paraphyletic. Moreover, cells with hexagonal periplast plates were found in an SEM preparation from material of the type species C. nordstedtii. In this study, material of Hansgirg’s C. nordstedtii was subjected to PCR and to sequencing of two short DNA tags. These tags allowed for an unambiguous identification of the real C. nordstedtii in the phylogeny of the blue-green cryptophytes. The genus Chroomonas corresponds to subclade 1, whereas subclades 3 and 4 do not belong to Chroomonas, if Hemiselmis is maintained. Additional examination by light and scanning electron microscopy and by spectrophotometry demonstrate that subclade 1 comprises only cells with hexagonal periplast plates and PC 630, whereas rectangular periplast plates are found only in subclades 3 and 4. Consequently the genus Chroomonas and its type species, C. nordstedtii, are revised and two novel species, C. debatzensis and C. gentoftensis sp. nov., are described.
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osmotolerance in the cryptophyceae jacks of all trades in the Chroomonas clade
Protist, 2014Co-Authors: Kerstin HoefemdenAbstract:No detailed studies have been performed to date on osmotolerance in cryptophytes, although one species, Chroomonas africana, had previously been reported to grow in freshwater as well as seawater. This study focused on osmotolerance in Chroomonas. Growth at different osmolalities and parameters of contractile vacuole function were examined and compared across a high-resolution phylogeny. Two evolutionary lineages in the Chroomonas clade proved to be euryhaline. Ranges of osmotolerance depended not only on osmolality, but also on culture medium. All cryptophytes contained contractile vacuoles. In the euryhaline strain CCAP 978/08 contractile vacuoles could be observed even at an osmolality beyond that of seawater. In addition the cells accumulated floridoside, an osmoprotectant likely originating from the red algal carbohydrate metabolism of the complex rhodoplast. Further evidence for functional contractile vacuoles also in marine cryptophytes was provided by identification of contractile vacuole-specific genes in the genome of Guillardia theta.