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@article{faucris.260271621,
abstract = {Euglena gracilis (E. gracilis) is an attractive organism due to its evolutionary history and substantial potential to produce biochemicals of commercial importance. This study describes the establishment of an optimized protocol for the genetic transformation of E. gracilis mediated by Ag-robacterium (A. tumefaciens). E. gracilis was found to be highly sensitive to hygromycin and zeocin, thus offering a set of resistance marker genes for the selection of transformants. A. tumefaciens‐me-diated transformation (ATMT) yielded hygromycin‐resistant cells. However, hygromycin‐resistant cells hosting the gus gene (encoding β‐glucuronidase (GUS)) were found to be GUS‐negative, indi-cating that the gus gene had explicitly been silenced. To circumvent transgene silencing, GUS was expressed from the nuclear genome as transcriptional fusions with the hygromycin resistance gene (hptII) (encoding hygromycin phosphotransferase II) with the foot and mouth disease virus (FMDV)‐derived 2A self‐cleaving sequence placed between the coding sequences. ATMT of Euglena with the hptII‐2A–gus gene yielded hygromycin‐resistant, GUS‐positive cells. The transformation was verified by PCR amplification of the T‐DNA region genes, determination of GUS activity, and indirect immunofluorescence assays. Cocultivation factors optimization revealed that a higher number of transformants was obtained when A. tumefaciens LBA4404 (A600 = 1.0) and E. gracilis (A750 = 2.0) cultures were cocultured for 48 h at 19 °C in an organic medium (pH 6.5) containing 50 μM acetosyringone. Transformation efficiency of 8.26 ± 4.9% was achieved under the optimized cocul-tivation parameters. The molecular toolkits and method presented here can be used to bioengineer E. gracilis for producing high‐value products and fundamental studies.},
author = {Becker, Ina and Prasad, Binod and Ntefidou, Maria and Daiker, Viktor and Richter, Peter and Lebert, Michael},
doi = {10.3390/ijms22126299},
faupublication = {yes},
journal = {International Journal of Molecular Sciences},
keywords = {Agrobacterium tumefaciens; Euglena gracilis; Gene silencing; Genetic engineering; Transformation},
note = {CRIS-Team Scopus Importer:2021-06-18},
peerreviewed = {Yes},
title = {{Agrobacterium} tumefaciens‐mediated nuclear transformation of a biotechnologically important microalga—euglena gracilis},
volume = {22},
year = {2021}
}
@article{faucris.121086944,
abstract = {In recent times Euglena gracilis Z was employed as primary producer in closed environmental life-support system (CELSS), e.g. in space research. The photosynthetic unicellular flagellate is not capable of utilizing nitrate, nitrite, and urea as nitrogen source. Therefore, ammonium is supplied as an N-source in the lab (provided as diammonium-dihydrogenphosphate, (NH)HPO) to E. gracilis cultures. While nitrate exerts low toxicity to organisms, ammonium is harmful for many aquatic organisms especially, at high pH-values, which causes the ionic NH4+ (low toxicity) to be partially transformed into the highly toxic ammonia, NH. In earlier reports, Euglena gracilis was described to grow with various amino acids as sole N-source. Our aim was to investigate alternatives for (NH)HPO as N-source with lower toxicity for organisms co-cultivated with Euglena in a CELSS. The growth kinetics of Euglena gracilis cultures was determined in the presence of different amino acids (glycine, glutamine, glutamic acid, leucine, and threonine). In addition, uptake of those amino acids by the cells was measured. Cell growth in the presence of glycine and glutamine was quite comparable to the growth in (NH)HPO containing cultures while a delay in growth was observed in the presence of leucine and threonine. Unlike, aforementioned amino acids glutamate consumption was very poor. Cell density and glutamate concentration were almost unaltered throughout the experiment and the culture reached the stationary phase within 8 days. The data are compared with earlier studies in which utilization of amino acids in Euglena gracilis was investigated. All tested amino acids (glutamate with limitations) were found to have the potential of being an alternative N-source for Euglena gracilis. Hence, these amino acids can be used as a non-toxic surrogate for (NH)HPO.},
author = {Richter, Peter and Liu, Y. and An, Y. and Li, X. and Nasir, Adeel and Strauch, Sebastian and Becker, Ina and Krüger, Julia and Schuster, Martin and Ntefidou, Maria and Daiker, Viktor and Haag, Ferdinand and Aiach, A. and Lebert, Michael},
doi = {10.1016/j.lssr.2014.11.001},
faupublication = {yes},
journal = {Life Sciences in Space Research},
keywords = {Amino-acids; CELSS; Euglena gracilis; Nitrogen source},
pages = {1-5},
peerreviewed = {Yes},
title = {{Amino} acids as possible alternative nitrogen source for growth of {Euglena} gracilis {Z} in life support systems},
volume = {4},
year = {2015}
}
@article{faucris.215902074,
abstract = {Tip growth of pollen tubes, root hairs, and apical cells of moss protonemata is controlled by ROP (Rho of plants) GTPases, which were shown to accumulate at the apical plasma membrane of these cells. However, most ROP localization patterns reported in the literature are based on fluorescent protein tagging and need to be interpreted with caution, as ROP fusion proteins were generally overexpressed at undefined levels, in many cases without assessing effects on tip growth. ROP-GEFs, important regulators of ROP activity, were also described to accumulate at the apical plasma membrane during tip growth. However, to date only the localization of fluorescent ROP-GEF fusion proteins strongly overexpressed using highly active promoters have been investigated. Here, the intracellular distributions of fluorescent PpROP1 and PpROP-GEF4 fusion proteins expressed at essentially endogenous levels in apical cells of Physcomitrella patens “knock-in” protonemata were analyzed. Whereas PpROP-GEF4 was found to associate with a small apical plasma membrane domain, PpROP1 expression was below the detection limit. Estradiol-titratable expression of a fluorescent PpROP1 fusion protein at the lowest detectable level, at which plant development was only marginally affected, was therefore employed to show that PpROP1 also accumulates at the apical plasma membrane, although within a substantially larger domain. Interestingly, RNA-Seq data indicated that the majority of all genes active in protonemata are expressed at lower levels than PpROP1, suggesting that estradiol-titratable expression may represent an important alternative to “knock-in” based analysis of the intracellular distribution of fluorescent fusion proteins in protonemal cells.
4 pathway.},
author = {Shiko, Glendis and Paulmann, Max Jonas and Feistel, Felix and Ntefidou, Maria and Hermann-Ene, Vanessa and Vetter, Walter and Kost, Benedikt and Kunert, Grit and Zedler, Julie A.Z. and Reichelt, Michael and Oelmüller, Ralf and Klein, Jan},
doi = {10.1111/nph.19163},
faupublication = {yes},
journal = {New Phytologist},
keywords = {androgens; Arabidopsis thaliana; Chlamydomonas reinhardtii; Hordeum vulgare; Physcomitrium patens; progestogens; Spirodela polyrhiza; steroidogenesis},
note = {CRIS-Team Scopus Importer:2023-08-18},
peerreviewed = {Yes},
title = {{Occurrence} and conversion of progestogens and androgens are conserved in land plants},
year = {2023}
}
@article{faucris.119414284,
abstract = {Euglena gracilis, a unicellular freshwater protist exhibits different photomovement responses, such as phototaxis (oriented movement toward or away from the light source) and photophobic (abrupt turn in response to a rapid increase [step-up] or decrease [step-down] in the light fluence rate) responses. Photoactivated adenylyl cyclase (PAC) has been isolated from whole-cell preparations and identified by RNA interference (RNAi) to be the photoreceptor for step-up photophobic responses but not for step-down photophobic responses (M. Iseki, S. Matsunaga, A. Murakami, K. Ohno, K. Shiga, C. Yoshida, M. Sugai, T. Takahashi, T. Hori, M. Watanabe [2002] Nature 415: 1047-1051). The present study shows that knockdown of PAC by RNAi also effectively suppresses both positive and negative phototaxis, indicating for the first time that PAC or a PAC homolog is also the photoreceptor for photoorientation of wild-type E. gracilis. Recovery from RNAi occurred earlier for step-up photophobic responses than for positive and negative phototaxis. In addition, we investigated several phototaxis mutant strains of E. gracilis with different cytological features regarding the stigma and paraxonemal body (PAB; believed to be the location for the phototaxis photoreceptor) as well as Astasia longa, a close relative of E. gracilis. All of the E. gracilis mutant strains had PAC mRNAs, whereas in A. longa, a different but similar mRNA was found and designated AlPAC. Consistently, all of these strains showed no phototaxis but performed step-up photophobic responses, which were suppressed by RNAi of the PAC mRNA. The fact that some of these strains possess a cytologically altered or no PAB demonstrates that at least in these strains, the PAC photoreceptor responsible for the step-up photophobic responses is not located in the PAB.},
author = {Lebert, Michael and Ntefidou, Maria and et al.},
author_hint = {Ntefidou M, Iseki M, Watanabe M, Lebert M, Hader DP},
doi = {10.1104/pp.103.034223},
faupublication = {yes},
journal = {Plant Physiology},
pages = {1517-1521},
peerreviewed = {Yes},
support_note = {Author relations incomplete. You may find additional data in field 'author{\_}hint'},
title = {{Photoactivated} adenylyl cyclase controls phototaxis in the flagellate {Euglena} gracilis},
volume = {133},
year = {2003}
}
@inproceedings{faucris.108818424,
abstract = {The unicellular, green flagellate wild-type Euglena gracilis ( strain Z) and its colorless phototaxis-mutant strains as well as the non-photosynthetic close relative, Astasia longa, possess several genes of the photoactivated adenylyl cyclase (PAC) family. The corresponding gene products were found to be responsible for step-up ( but not step-down) photophobic responses as well as both positive and negative phototaxis. The proteins consist of two PAC alpha (M-r 105 kDa) and two PAC beta ( 90 kDa) subunits. While the proteins were first believed all to be located in the paraxonemal body (PAB), confocal microscopy revealed that Astasia longa as well as some of the mutant strains do not contain a PAB. Immunofluorescence using PAC antibodies showed that the PAC proteins are also located along the total length of the flagellum at least in some of the strains. In order to determine if the genes responsible for the PAC proteins in the PAB and flagella are identical, sequences of all PAC proteins were analyzed in the Euglena and Astasia strains studied for PAC protein location. Full sequence analysis using PCR and 3' and 5' RACE indicated a substantial divergence between strains with a homology between strains of between 45 and 100%. Sequence alignment and sequence tree construction for the main functional groups (BLUF domain, which binds FAD, and adenylyl cyclase) showed that the paca and the pac beta gene products form clusters each with some of the mutants being closely related while others show a substantial degree of genetic diversity. The conclusion of these results is that there is a family of very dissimilar PAC proteins located in the PAB and the flagellum where they serve different functions in phototaxis and step-up photophobic reactions.},
author = {Ntefidou, Maria and Häder, Donat-Peter},
doi = {10.1039/b502002f},
faupublication = {yes},
month = {Jan},
pages = {732-739},
peerreviewed = {unknown},
publisher = {ROYAL SOC CHEMISTRY},
title = {{Photoactivated} adenylyl cyclase ({PAC}) genes in the agellate {Euglena} gracilis mutant strains},
volume = {4},
year = {2005}
}
@article{faucris.289677535,
abstract = {RHO guanosine triphosphatases are important eukaryotic regulators of cell differentiation and behavior. Plant ROP (RHO of plant) family members activate specific, incompletely characterized downstream signaling. The structurally simple land plant Physcomitrium patens is missing homologs of key animal and flowering plant RHO effectors but contains a single CRIB (CDC42/RAC interactive binding)-domain-containing RIC (ROP-interacting CRIB-containing) protein (PpRIC). Protonemal P. patens filaments elongate based on regular division and PpROP-dependent tip growth of apical initial cells, which upon stimulation by the hormone auxin differentiate caulonemal characteristics. PpRIC interacts with active PpROP1, co-localizes with this protein at the plasma membrane at the tip of apical initial cells, and accumulates in the nucleus. Remarkably, PpRIC is not required for tip growth but is targeted to the nucleus to block caulonema differentiation downstream of auxin-controlled gene expression. These observations establish functions of PpRIC in mediating crosstalk between ROP and auxin signaling, which contributes to the maintenance of apical initial cell identity.},
author = {Ntefidou, Maria and Eklund, D. Magnus and le Bail, Aude and Schulmeister, Sylwia and Scherbel, Franziska and Brandl, Lisa and Dörfler, Wolfgang and Eichstädt, Chantal and Bannmüller, Anna and Ljung, Karin and Kost, Benedikt},
doi = {10.1016/j.celrep.2023.112130},
faupublication = {yes},
journal = {Cell Reports},
keywords = {auxin; cell differentiation; CP: Developmental biology; CP: Plants; CRIB domain; initial cells; land plant evolution; nuclear targeting; Physcomitrium patens; RHO/ROP effectors; RHO/ROP GTPases; tip growth},
note = {CRIS-Team Scopus Importer:2023-02-24},
peerreviewed = {Yes},
title = {{Physcomitrium} patens {PpRIC}, an ancestral {CRIB}-domain {ROP} effector, inhibits auxin-induced differentiation of apical initial cells},
volume = {42},
year = {2023}
}
@article{faucris.122014464,
abstract = {Pollen tube tip growth is a widely used model ideally suited to study cellular processes underlying polarized cell expansion. Local secretion supplying material for plasma membrane (PM) and cell wall extension is essential for this process. Cell wall biogenesis requires fusion of secretory vesicles with the PM at an about 10× higher rate than PM extension. Excess material is therefore incorporated into the PM, which needs to be reinternalized through endocytosis. The classical model of tip growth proposes that exocytosis occurs at the apex and that newly incorporated PM material is transported to adjacent lateral regions, where excess material is endocytically recycled. This model was recently challenged based on studies indicating that lateral exocytosis may be balanced by apical endocytosis. This review provides an overview of published data pertaining to exocytosis, endocytosis and vesicular trafficking in pollen tubes. Its key aim is to present classical and alternative models of tip growth in the light of available experimental data. By necessity, the review focusses on pollen tubes of angiosperm models (Nicotiana tabacum, Arabidopsis, Lilium longiflorum), which have been studied far more extensively and grow much faster than structurally strikingly different gymnosperm pollen tubes. Only major transport pathways are considered, which substantially contribute to the mass-flow of membrane material at the pollen tube tip. Growth oscillation, which may be displayed in particular by fast-growing pollen tubes, are not discussed as their influence on the spatial organization of apical membrane traffic is not understood.},
author = {Grebnev, Gleb and Ntefidou, Maria and Kost, Benedikt},
doi = {10.3389/fpls.2017.00154},
faupublication = {yes},
journal = {Frontiers in Plant Science},
keywords = {pollen tube; tip growth; polarized growth; secretion/exocytosis; endocytosis; membrane recycling},
peerreviewed = {Yes},
title = {{Secretion} and {Endocytosis} in {Pollen} {Tubes}: {Models} of {Tip} {Growth} in the {Spot} {Light}},
volume = {8},
year = {2017}
}
@article{faucris.119421984,
abstract = {Euglena gracilis is a single-celled freshwater flagellate which shows, among other movement behaviors, a negative gravitaxis (cells swim upward in the water column) and a pronounced phototaxis. Gravitaxis is most likely an active physiological mechanism, and the influence of various inhibitors on the gravitaxis in Euglena gracilis was tested using the fully automatic image analysis system ECO-TOX to elucidate the possible cellular mechanism of gravity perception and signal transduction. Substances such as the phosphodiesterase inhibitors theophylline, IBM-X and forskolin, which increase the intracellular cAMP concentration, enhance the precision of graviorientation of the cells measured shortly after incubation. Indomethacin, which decreases the intracellular cAMP concentration by inhibition of the adenylate cyclase, inhibited graviorientation. All inhibitors of calmodulin metabolism tested reduced the precision of gravitaxis in Euglena gracilis. Heparin and LiCl, which inhibit the IP3-pathway (block IP3 channels or formation of IP3, respectively) had no effect. The potassium channel blockers BaCl2 and CsCl showed an effect on the orientation behavior, while tetraethylammonium (TEA) had no influence. The protein phosphatase inhibitor, ocadaic acid, inhibited graviorientation at low concentrations. The data are discussed with respect to the current working model for gravitaxis in Euglena gracilis.},
author = {Streb, Christine and Richter, Peter and Ntefidou, Maria and Lebert, Michael and Häder, Donat-Peter},
doi = {10.1078/0176-1617-00769},
faupublication = {yes},
journal = {Journal of Plant Physiology},
keywords = {calmodulin;cyclic nucleotides;Euglena gracilis;flagellates;gravitaxis;sensory transduction},
pages = {855-862},
peerreviewed = {Yes},
title = {{Sensory} transduction of gravitaxis in {Euglena} gracilis},
volume = {159},
year = {2002}
}
@article{faucris.123589664,
abstract = {The German Aerospace Center (DLR) enabled German participation in the joint space campaign on the unmanned Shenzhou 8 spacecraft in November 2011. In this report, the effect of microgravity on Euglena gracilis cells is described. Custom-made dual compartment cell fixation units (containing cells in one chamber and fixative - RNA lysis buffer - in another one) were enclosed in a small container and placed in the Simbox incubator, which is an experiment support system. Cells were fixed by injecting them with fixative at different time intervals. In addition to stationary experiment slots, Simbox provides a 1g reference centrifuge. Cell fixation units were mounted in microgravity and 1g reference positions of Simbox. Two Simbox incubators were used, one for space flight and the other as ground reference. Cells were fixed soon after launch and shortly before return of the spaceship. Due to technical problems, only early in-flight samples (about 40min after launch microgravity and corresponding 1g reference) were fully mixed with fixative, therefore only data from those samples are presented. Transcription of several genes involved in signal transduction, oxidative stress defence, cell cycle regulation and heat shock responses was investigated with quantitative PCR. The data indicate that Euglena cells suffer stress upon short-term exposure to microgravity; various stress-induced genes were up-regulated. Of 32 tested genes, 18 were up-regulated, one down-regulated and the rest remained unaltered. These findings are in a good agreement with results from other research groups using other organisms.},
author = {Nasir, Adeel and Strauch, Sebastian and Becker, Ina and Sperling, Anna and Schuster, Martin and Richter, Peter and Weißkopf, Matthias and Ntefidou, Maria and Daiker, Viktor and An, Y. A. and Li, X. Y. and Liu, Y. D. and Lebert, Michael},
doi = {10.1111/plb.12067},
faupublication = {yes},
journal = {Plant Biology},
keywords = {Euglena gracilis;gene expression;microgravity;qPCR;space flight;unicellular flagellate},
month = {Jan},
pages = {113-119},
peerreviewed = {Yes},
title = {{The} influence of microgravity on {Euglena} gracilis as studied on {Shenzhou} 8},
volume = {16},
year = {2014}
}