Morphological relationship between paraflagellar swelling and paraxial rod in Euglena Gracilis

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

doi:10.1016/0739-6260(92)90071-k

Cited by 21 publications

(7 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11.2). A paraxonemal rod (PAR) inside the flagellum connects the PAB to the cell matrix (Banchetti et al 1980;Hyams 1982;Verni et al 1992;Karnkowska et al 2015). It consists of several proteins like in trypanosomes, the function of which is still unclear (Hyams 1982;Leedale 1982;Ngô and Bouck 1998).…”

Section: The Organismsmentioning

confidence: 97%

Photomovement in Euglena

Häder

Iseki

2017

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

Motile microorganisms such as the green Euglena gracilis use a number of external stimuli to orient in their environment. They respond to light with photophobic responses, photokinesis and phototaxis, all of which can result in accumulations of the organisms in suitable habitats. The light responses operate synergistically with gravitaxis, aerotaxis and other responses. Originally the microscopically obvious stigma was thought to be the photoreceptor, but later the paraxonemal body (PAB, paraflagellar body) has been identified as the light responsive organelle, located in the trailing flagellum inside the reservoir. The stigma can aid in light direction perception by shading the PAB periodically when the cell rotates helically in lateral light, but stigmaless mutants can also orient with respect to the light direction, and negative phototaxis does not need the presence of the stigma. The PAB is composed of dichroically oriented chromoproteins which is reflected in a pronounced polarotaxis in polarized light. There was a long debate about the potential photoreceptor molecule in Euglena, including carotenoids, flavins and rhodopsins. This discussion was terminated by the unambiguous proof that the photoreceptor is a 400 kDa photoactivated adenylyl cyclase (PAC) which consists of two α- and two β-subunits each. Each subunit possesses two BLUF (Blue Light receptor Using FAD) domains binding FAD, which harvest the light energy, and two adenylyl cyclases, which produce cAMP from ATP. The cAMP has been found to activate one of the five protein kinase s found in Euglena (PK.4). This enzyme in turn is thought to phosphorylate proteins inside the flagellum which result in a change in the flagellar beating pattern and thus a course correction of the cell. The involvements of PAC and protein kinase have been confirmed by RNA interference (RNAi). PAC is responsible for step-up photophobic responses as well as positive and negative phototaxis, but not for the step-down photophobic response, even though the action spectrum of this resembles those for the other two responses. Analysis of several colorless Euglena mutants and the closely related Euglena longa (formerly Astasia longa) confirms the results. Photokinesis shows a completely different action spectrum. Some other Euglena species, such as E. sanguinea and the gliding E. mutabilis, have been investigated, again showing totally different action spectra for phototaxis and photokinesis as well as step-up and step-down photophobic responses.

show abstract

Section: The Organismsmentioning

confidence: 97%

Photomovement in Euglena

Häder

Iseki

2017

Advances in Experimental Medicine and Biology

View full text Add to dashboard Cite

show abstract

“…Euglena uses sunlight as a source of energy and information. Its chloroplasts supply the energy for metabolic processes, whereas a simple but sophisticated system, consisting of a stigma and a photoreceptor, functions as a light detector (3–5). As the cell rotates while swimming, the stigma comes between the light source and the photoreceptor, thus modulating the light that reaches it and giving rise to the signal that regulates the steering of the locomotory flagellum.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence Behavior of Euglena Photoreceptor¶

Evangelista

Passarelli

Barsanti

et al. 2007

Photochemistry and Photobiology

Self Cite

View full text Add to dashboard Cite

To provide new information on the series of structural changes that Euglena photoreceptive proteins undergo inside the photoreceptor in response to light, we measured in vivo emission fluorescence spectra in the stable intermediates of its photocycle. Our emission spectra give a certain indication that fluorescent proteins are present in the Euglena photoreceptor and that they undergo a photocycle. On the basis of our data, we suggested that at least two stable intermediates, one of which is fluorescent, can be discriminated at room temperature and with our time resolution.

show abstract

“…In addition, we found 13 proteins of the paraflagellar rod, a structure observed in euglenids, kinetoplastids and dinoflagellates [109][110][111]. Such a structure is associated with the paraflagellar body (also called paraxonemal body, PAB) in E. gracilis [112]. We also found 49 transcripts coding for photoactivated adenylate cyclases (PAC), which are light-sensitive proteins of PAB [113].…”

Section: Functional Annotation Of Transcriptsmentioning

confidence: 91%

De Novo Transcriptome Meta-Assembly of the Mixotrophic Freshwater Microalga Euglena gracilis

Córdoba

Perez

Vlierberghe

et al. 2021

Genes

View full text Add to dashboard Cite

Euglena gracilis is a well-known photosynthetic microeukaryote considered as the product of a secondary endosymbiosis between a green alga and a phagotrophic unicellular belonging to the same eukaryotic phylum as the parasitic trypanosomatids. As its nuclear genome has proven difficult to sequence, reliable transcriptomes are important for functional studies. In this work, we assembled a new consensus transcriptome by combining sequencing reads from five independent studies. Based on a detailed comparison with two previously released transcriptomes, our consensus transcriptome appears to be the most complete so far. Remapping the reads on it allowed us to compare the expression of the transcripts across multiple culture conditions at once and to infer a functionally annotated network of co-expressed genes. Although the emergence of meaningful gene clusters indicates that some biological signal lies in gene expression levels, our analyses confirm that gene regulation in euglenozoans is not primarily controlled at the transcriptional level. Regarding the origin of E. gracilis, we observe a heavily mixed gene ancestry, as previously reported, and rule out sequence contamination as a possible explanation for these observations. Instead, they indicate that this complex alga has evolved through a convoluted process involving much more than two partners.

show abstract

Morphological relationship between paraflagellar swelling and paraxial rod in Euglena Gracilis

Cited by 21 publications

References 21 publications

Photomovement in Euglena

Photomovement in Euglena

Fluorescence Behavior of Euglena Photoreceptor¶

De Novo Transcriptome Meta-Assembly of the Mixotrophic Freshwater Microalga Euglena gracilis

Contact Info

Product

Resources

About