Evidence for ciliary pigment localization in colored ciliates and implications for their photosensory transduction chain: A confocal microscopy study

Colombetti, Giuliano; Checcucci, Giovanni; Lucia, S.; Usai, Cesare; Ramoino, Paola; Bianchini, Paolo; Pesce, Mattia; Vicidomini, Giuseppe; Diaspro, Alberto

doi:10.1002/jemt.20508

Cited by 4 publications

(1 citation statement)

References 13 publications

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“…S. amethystinus collected from rich blooms was found to contain high concentrations of amethystin ( 4 ), whereas sparingly occurring organisms appear uncolored and contain more than 10-fold less pigment. From that, it could be speculated that the very small amounts of pigments are localized in the cilia responsible for photodetection, while larger amounts are concentrated in the granula during a bloom for defense.…”

Section: Resultsmentioning

confidence: 99%

Amethystin, the Coloring Principle of Stentor amethystinus

et al. 2014

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Among the ciliates, Stentor amethystinus stands out for its conspicuous red-violet color compared to its blue- and red-colored relatives Stentor coeruleus and Blepharisma japonicum. Rich blooms in German lakes allowed us to collect sufficient organisms to isolate the pigments and elucidate the structure of the main component amethystin (4) by spectroscopic methods as a carboxy derivative of blepharismin. Depending on conditions, the carboxy group appears as an orthoester or as a mixture of the orthoester and small amounts of a hydroxylactone. Derivatives of both isomeric forms were obtained by acetylation and methylation supporting the proposed structures. On reaction of amethystin with base in the presence of oxygen, oxyamethystin and, under vigorous conditions, p-hydroxybenzoic acid were formed. In addition to 4, two homologues, an isomer of amethystin, and stentorin F (1b) were identified in the primary extract. Further, a biosynthetic scheme is proposed linking stentorin, blepharismin, and amethystin type compounds to the hypothetical protostentorin as a common intermediate.

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Section: Resultsmentioning

confidence: 99%

Amethystin, the Coloring Principle of Stentor amethystinus

et al. 2014

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Unicellular Organisms with Versatile Solutions at the Micro‐Scale: Functional Materials and Principles in Ciliates

Dörr,

Kohl,

Schweikert

et al. 2023

Adv Funct Materials

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Nature's diversity offers an abundance of promising solutions for novel bioinspired functional materials and systems. In particular, single‐celled organisms exhibit solutions and material properties that are realized at the nano‐ and micro‐scales. Ciliates are ubiquitous unicellular eukaryotes that are well‐adapted to a wide range of environmental conditions. They have developed a large variety of interesting and highly specialized characteristics with unique properties and design. In this review, the background of selected ciliate characteristics is highlighted with respect to material properties and structure‐function relationships. Hierarchically complex mineralized structures, highly efficient sensors for movement and protection, shape‐memory structures, as well as survival and detoxification strategies are to be emphasized. Proposed future bioinspired applications of these properties of ciliates expand the possibilities to more sustainable materials and development processes.

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Fluorescence lifetime microscopy reveals the biologically-related photophysical heterogeneity of oxyblepharismin in light-adapted (blue) Blepharisma japonicum cells

Checcucci

Storti

Ghetti

et al. 2017

Photochem Photobiol Sci

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The step-up photophobic response of the heterotrich ciliate Blepharisma japonicum is mediated by a hypericinic pigment, blepharismin, which is not present in any of the known six families of photoreceptors, namely rhodopsins, phytochromes, xanthopsins, cryptochromes, phototropins, and BLUF proteins. Upon irradiation, native cells become light-adapted (blue) by converting blepharismin into the photochemically stable oxyblepharismin (OxyBP). So far, OxyBP has been investigated mainly from a photophysical point of view in vitro, either alone or complexed with proteins. In this work, we exploit the vivid fluorescence of OxyBP to characterize its lifetime emission in blue B. Japonicum cells, on account of the recognized role of the fluorescence lifetime to provide physicochemical insights into the fluorophore environment at the nanoscale. In a biological context, OxyBP modifies its emission lifetime as compared to isotropic media. The phasor approach to fluorescence lifetime microscopy in confocal mode highlights that fluorescence originates from two excited states, whose relative balance changes throughout the cell body. Additionally, Cilia and kinetids, i.e., the organelles involved in photomovement, display lifetime asymmetry between the anterior and posterior part of the cell. From these data, some hypotheses on the phototransduction mechanism are proposed.

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Evidence for ciliary pigment localization in colored ciliates and implications for their photosensory transduction chain: A confocal microscopy study

Cited by 4 publications

References 13 publications

Amethystin, the Coloring Principle of Stentor amethystinus

Amethystin, the Coloring Principle of Stentor amethystinus

Unicellular Organisms with Versatile Solutions at the Micro‐Scale: Functional Materials and Principles in Ciliates

Fluorescence lifetime microscopy reveals the biologically-related photophysical heterogeneity of oxyblepharismin in light-adapted (blue) Blepharisma japonicum cells

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