Ultrastructure and phototactic action spectra of two genera of cryptophyte flagellate algae, Cryptomonas and Chroomonas

Erata, Mayumi; Kubota, Mamoru; Takahashi, Tetsuo; Inouye, Isao; Watanabe, Masakatsu

doi:10.1007/bf01280378

Cited by 25 publications

(20 citation statements)

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“…Action spectroscopy is a crucially important method that provides basic information for identification of photoreceptor molecules mediating a certain photochemical or photobiological response: if carefully determined, an action spectrum should match the absorption spectrum of the photoreceptor (Schfifer and Fukshansky 1984, Lipson 1995, Watanabe 1995. On the basis of action spectra determined for the photodispersal response (Diehn 1969a) and photoaccumulation (Checcucci et al 1976), flavin-like chromophores were suggested as candidates for the photoreceptor pigment mediating Euglena photomovements.…”

Section: Introductionmentioning

confidence: 99%

“…In this study we extended the spectral range of the action spectra into the UV-B/C region (260-320 nm). Action spectral data in the UV-B/C region are useful for determining the nature of the photoreceptor(s) in various plant and microbial organisms (Watanabe 1991(Watanabe , 1995. The extension into the UV-B/C region in a variety of organisms was made possible by using the Okazaki Large Spectrograph (OLS) at the National Institute for Basic Biology (NIBB).…”

Section: Introductionmentioning

confidence: 99%

“…Despite many attempts with photophysiological approaches such as action spectroscopy, the chemical identity of the photoreceptor has remained controversial (Watanabe 1995). Recently, by a T-DNA tagging technique, a gene (HY4) encoding a flavin-type blue-light photoreceptor was cloned and sequenced from a dicot plant, Arabidopsis thaliana (Ahmad and Cashmore 1993).…”

Section: Introductionmentioning

confidence: 99%

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Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the unicellular flagellate algaEuglena gracilis

et al. 1998

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Summary. Cultures of unicellular algal flagellate Euglena gracilisgrown in different conditions were subjected to action spectroscopy for step-down and step-up photophobic responses, respectively. The spectral region was extended into the UV-B/C as well as in the UV-A and visible regions with the Okazaki Large Spectrograph as the monochromatic light source. The photophobic responses of the cells were measured with an individual-cell assay method with the aid of a computerized video motion analyzer. In the UV-A and visible regions, the shapes of the action spectra were the so-called UV-A/blue type. In the newly studied UV-B/C region, new action peaks were found at 270 nm for the step-down response and at 280 nm for the step-up one. The absorption spectrum of flavin adenine dinucleotide (FAD) appeared to fit the action spectrum for the stepup response, whereas the shape of the step-down action spectrum, which has a UV-A peak (at 370 nm) higher than the blue peak (at 450 rim), appeared to be mimicked by the absorption spectrum of a mixed solution of 6-biopterin and FAD. These observations might also account for the fact that the UV-B/C peak wavelength at 270 nm of the action spectrum for the step-down response is shorter by 10 nm than the action spectrum for the step-up response at 280 nm.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the unicellular flagellate algaEuglena gracilis

et al. 1998

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“…Investigations of marine cryptophyte communities with a dilution cultures method (Cerino and Zingone 2006) and molecular techniques (Metfies et al 2010) revealed a pronounced seasonality of cryptophyte species, suggesting that the commonly used class-level approach is over-simplifying. Furthermore, species-specific aspects of cryptophyte ecology, such as mixotrophy (Tranvik et al 1989, Roberts andLaybourn-Parry 1999), vertical migrations (Erata et al 1995), high tolerance to environmental changes (Klaveness 1988) and interactions with other organisms such as dinoflagellates (Hackett et al 2003, Park et al 2006) and ciliates (Hansen and Fenchel 2006) indicate the ecological and physiological complexity of the group.…”

Section: Introductionmentioning

confidence: 99%

Cryptophyte bloom in a Mediterranean estuary: High abundance of <em>Plagioselmis</em> cf. <em>prolonga</em> in the Krka River estuary (eastern Adriatic Sea)

et al. 2014

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Summary:During the June 2010 survey of phytoplankton and physicochemical parameters in the Krka River estuary (eastern Adriatic Sea), a cryptophyte bloom was observed. High abundance of cryptophytes (maximum 7.9×10 6 cells l -1 ) and high concentrations of the class-specific biomarker pigment alloxanthine (maximum 2312 ng l -1 ) were detected in the surface layer and at the halocline in the lower reach of the estuary. Taxonomical analysis revealed that the blooming species was Plagioselmis cf. prolonga. Analysis of the environmental parameters in the estuary suggested that the bloom was supported by the slower river flow as well as the increased orthophosphate and ammonium concentrations. The first record of a cryptophyte bloom in the Krka River estuary may indicate that large-scale changes are taking place in the phytoplankton community. Such changes could have a major impact on the natural ecosystem dynamics and the mariculture production in the area.Keywords: estuarine ecosystem; phytoplankton bloom; cryptophytes; chemotaxonomy; Mediterranean Sea; Krka River estuary.Proliferación de una criptófita en un estuario mediterráneo: alta abundancia de Plagioselmis cf. prolonga en el estuario del río Krka (Adriático) Resumen: Se observó una proliferación de una criptófita durante el estudio del fitoplancton y de los parámetros fisicoquími-cos en el estuario del río Krka (Adriático) en junio de 2010. La abundancia más alta de criptofitas (máximo 7.9×10 6 células l -1 ) y las mayores concentraciones del pigmento marcador específico de la clase, la aloxantina (máximo 2312 ng l -1 ), fueron detectados en la capa superficial y en la haloclina en el tramo inferior de la ría. El análisis taxonómico reveló que la especie que proliferó fue Plagioselmis cf. prolonga. El análisis de los parámetros ambientales del estuario sugirió que la proliferación estaba favorecida por el caudal lento del río, así como el aumento de las concentraciones de ortofosfato y amonio. El hecho de registrar por primera vez una proliferación de una criptófita en el estuario del río Krka podría indicar cambios a gran escala en la comunidad de fitoplancton. Tales cambios podrían tener un impacto importante en la dinámica de los ecosistemas naturales y la producción de la maricultura en la zona.Palabras clave: estuario; proliferación de fitoplancton; criptófitas; quimiotaxonomía; mar Mediterráneo; estuario del río Krka.Citation/Como citar este artículo: Šupraha L., Bosak S.,

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“…Peranema rhodopsin joins the growing list of nonanimal eukaryotic rhodopsins, including those identified in dinoflagellates by the evaluation of protein sequences (30) and action spectral analysis (11,12,18), in cryptophytes by action spectra (9,12) and protein sequence evaluation (22), in fungi by shifted action spectra (34) and protein sequence evaluation (3), and in green algae by shifted action spectra (16) and protein sequence evaluation (20,38). Two other probable groups with rhodopsins suggested by action spectra are the ciliates (12,25) and foramins (12).…”

Section: Discussionmentioning

confidence: 99%

Photoreceptor for Curling Behavior in Peranema trichophorum and Evolution of Eukaryotic Rhodopsins

Saranak

Foster

2005

Eukaryot Cell

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When it is gliding, the unicellular euglenoid Peranema trichophorum uses activation of the photoreceptor rhodopsin to control the probability of its curling behavior. From the curled state, the cell takes off in a new direction. In a similar manner, archaea such as Halobacterium use light activation of bacterio-and sensory rhodopsins to control the probability of reversal of the rotation direction of flagella. Each reversal causes the cell to change its direction. In neither case does the cell track light, as known for the rhodopsin-dependent eukaryotic phototaxis of fungi, green algae, cryptomonads, dinoflagellates, and animal larvae. Rhodopsin was identified in Peranema by its native action spectrum (peak at 2.43 eV or 510 nm) and by the shifted spectrum (peak at 3.73 eV or 332 nm) upon replacement of the native chromophore with the retinal analog n-hexenal. The in vivo physiological activity of n-hexenal incorporated to become a chromophore also demonstrates that charge redistribution of a short asymmetric chromophore is sufficient for receptor activation and that the following isomerization step is probably not required when the rest of the native chromophore is missing. This property seems universal among the Euglenozoa, Plant, and Fungus kingdom rhodopsins. The rhodopsins of animals have yet to be studied in this respect. The photoresponse appears to be mediated by Ca 2؉ influx.Since rhodopsins sharing sequence similarities are found in bacteria, archaea, eukaryotic microorganisms, and animals, it is possible to gain insight into the evolutionary progression and diversification leading to the receptor proteins of human visual photoreceptors as well as other photoreceptors. As part of this continuing project on the evolution and mechanisms of visual systems, the light-dependent responses of Peranema have been studied with respect to behavior, action spectra, the mechanism of activation, and signaling to the cell.Peranema trichophorum is a colorless eukaryotic phagotroph of the Euglenophyta that lives in fresh water (8). It does not have a chloroplast but rapidly deforms in shape and is very effective at capturing and eating prey (41). Peranema voraciously takes any particles into its body by phagocytosis (1). This "feeding behavior" is clearly and commonly observed under the microscope. Its life cycle is not well studied, but from light microscopic observations Peranema appears to have several distinct stages of growth. After the cells are put into fresh medium, which is initially low on waste products, one sees small round cells of about 10 to 15 m in diameter. These cells elongate into oval cells that swim freely in solution and fast in a helical euglenoid motion. Over 2 weeks, these cells elongate further to 25 to 70 m in length, remaining 10 m wide, and are seen to glide forward on a surface pulled by their leading anterior cilium, which is about the length of the cell body. (We use the word "cilium" rather than "eukaryotic flagellum" to describe the leading appendage that enables the cell to glide to e...

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Ultrastructure and phototactic action spectra of two genera of cryptophyte flagellate algae, Cryptomonas and Chroomonas

Cited by 25 publications

References 25 publications

Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the unicellular flagellate algaEuglena gracilis

Discovery of signaling effect of UV-B/C light in the extended UV-A/blue-type action spectra for step-down and step-up photophobic responses in the unicellular flagellate algaEuglena gracilis

Cryptophyte bloom in a Mediterranean estuary: High abundance of <em>Plagioselmis</em> cf. <em>prolonga</em> in the Krka River estuary (eastern Adriatic Sea)

Photoreceptor for Curling Behavior in Peranema trichophorum and Evolution of Eukaryotic Rhodopsins

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