Ultrastructure of the apical zone of Euglena gracilis: Photoreceptors and motor apparatus

Rosati, Giovanna; Verni, Franco; Barsanti, Laura; Passarelli, Vincenzo; Gualtieri, Paolo

doi:10.1016/0892-0354(91)90008-z

Cited by 39 publications

(12 citation statements)

References 56 publications

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“…They are photosynthetic, as well as heterotrophic (Buetow 1982). They are freeliving, possess an eyespot, a food vacuole and two flagella-one short and one long, which play both locomotory and sensory functions (Rosati et al 1991). They also possess a chloroplast which arose as a result of secondary endosymbiosis (Gibbs 1978;McFadden 2001).…”

Section: Introductionmentioning

confidence: 99%

Euglena gracilis Genome and Transcriptome: Organelles, Nuclear Genome Assembly Strategies and Initial Features

Ebenezer

Carrington

Lebert

et al. 2017

Advances in Experimental Medicine and Biology

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Euglena gracilis is a major component of the aquatic ecosystem and together with closely related species, is ubiquitous worldwide. Euglenoids are an important group of protists, possessing a secondarily acquired plastid and are relatives to the Kinetoplastidae, which themselves have global impact as disease agents. To understand the biology of E. gracilis, as well as to provide further insight into the evolution and origins of the Kinetoplastidae, we embarked on sequencing the nuclear genome; the plastid and mitochondrial genomes are already in the public domain. Earlier studies suggested an extensive nuclear DNA content, with likely a high degree of repetitive sequence, together with significant extrachromosomal elements. To produce a list of coding sequences we have combined transcriptome data from both published and new sources, as well as embarked on de novo sequencing using a combination of 454, Illumina paired end libraries and long PacBio reads. Preliminary analysis suggests a surprisingly large genome approaching 2 Gbp, with a highly fragmented architecture and extensive repeat composition. Over 80% of the RNAseq reads from E. gracilis maps to the assembled genome sequence, which is comparable with the well assembled genomes of T. brucei and T. cruzi. In order to achieve this level of assembly we employed multiple informatics pipelines, which are discussed here. Finally, as a preliminary view of the genome architecture, we discuss the tubulin and calmodulin genes, which highlight potential novel splicing mechanisms.

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Section: Introductionmentioning

confidence: 99%

Euglena gracilis Genome and Transcriptome: Organelles, Nuclear Genome Assembly Strategies and Initial Features

Ebenezer

Carrington

Lebert

et al. 2017

Advances in Experimental Medicine and Biology

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“…Euglena gracilis is a fresh water flagellated unicellular alga used as a photobiology tool by laboratories around the world since the turn of the century. This organism possesses a simple but sophisticated light detecting system, consisting of an eyespot formed by carotenoid globules and a photoreceptor (1). The structure of the photoreceptor can be defined as a super lattice made up of closely stacked protein‐membrane lamellae separated by an aqueous phase.…”

Section: Introductionmentioning

confidence: 99%

In Vivo Absorption Spectra of the Two Stable States of the Euglena Photoreceptor Photocycle

Barsanti

Coltelli

Evangelista

et al. 2009

Photochem & Photobiology

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Euglena gracilis possesses a simple but sophisticated light detecting system, consisting of an eyespot formed by carotenoids globules and a photoreceptor. The photoreceptor of Euglena is characterized by optical bistability, with two stable states. In order to provide important and discriminating information on the series of structural changes that Euglena photoreceptive protein(s) undergoes inside the photoreceptor in response to light, we measured the in vivo absorption spectra of the two stable states A and B of photoreceptor photocycle. Data were collected using two different devices, i.e. a microspectrophotometer and a digital microscope. Our results show that the photocycle and the absorption spectra of the photoreceptor possess strong spectroscopic similarities with a rhodopsin-like protein. Moreover, the analysis of the absorption spectra of the two stable states of the photoreceptor and the absorption spectrum of the eyespot suggests an intriguing hypothesis for the orientation of microalgae toward light.

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“…The eyespot, composed of red‐orange pigment granules, lies in the adjacent cytoplasm. Only one flagellum emerges from the cell and consists of an axoneme, a paraxial rod running parallel to it, and a photoreceptor near its base [1].…”

Section: Introductionmentioning

confidence: 99%

The photoreceptor protein of Euglena gracilis

et al. 2000

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We isolated the photoactive protein Erh, isolated from the photoreceptor of the unicellular photosynthetic flagellate Euglena gracilis. It is a 27 kDa protein with a photocycle resembling that of sensory rhodopsin, but with at least one stable intermediate. We recorded the absorption spectrum of the parent form of this protein both under native form and in the presence of hydroxylamine and sodium borohydride, and the fluorescence spectra of both the parent and intermediate forms.We suggest that Erh is a rhodopsin-like protein and propose a simple photocycle. This protein shows optical bistability, without thermal deactivation. ß

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Ultrastructure of the apical zone of Euglena gracilis: Photoreceptors and motor apparatus

Cited by 39 publications

References 56 publications

Euglena gracilis Genome and Transcriptome: Organelles, Nuclear Genome Assembly Strategies and Initial Features

Euglena gracilis Genome and Transcriptome: Organelles, Nuclear Genome Assembly Strategies and Initial Features

In Vivo Absorption Spectra of the Two Stable States of the Euglena Photoreceptor Photocycle

The photoreceptor protein of Euglena gracilis

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