Students can target a particular Euglena and try to control its movements using the LEDs.
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Riedel-Kruse's microbe of choice is Euglena, a tiny single-celled organism that's attracted to light.
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Most simply, kids can just watch their Euglena move around as they trigger the different light sources.
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Eu:CROPIS—short for the clunky Euglena and Combined Regenerative Organic-food Production in Space—will be outfitted with miniature automated green houses with tomato plants installed.
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According to a summary of the project from the college, the image above shows ciliates and single-celled euglena "acting" as Pac-Man by avoiding the multicellular rotifers that feed off of them.
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Scientists at the University of Southeast Norway have released microorganisms into a Pac-Man-style maze made out of fluid to observe how the single-celled euglena (in this case, Pac-Man) avoid their predators, the multi-celled rotifers.
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Using growth in personnel costs as rough guide, Mizuho identified some firms that might be candidates for an Abenomics ETF, including mobile game developer Colopl, sports-wear maker Asics Corp, office supplies firm Askul Corp and biofuel company Euglena Co Ltd.
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Undigested food is carried to the anal pore. Euglena Euglena is photosynthetic but also engulfs and digests microorganisms.
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Euglenophycin is an ichthyotoxic compound isolated from Euglena sanguinea, a protist of the genus Euglena. It exhibits anticancer and herbicidal activity in vitro.
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Euglena sanguinea is a species of the genus Euglena. The red colour is due to the presence of astaxanthin and the cells can be populous enough to colour water red. The pigment is used to protect the chloroplasts from light that is too intense, but as the light levels change the cells can take on a green colour as the red pigment is moved to the centre of the cells. Euglena sanguinea is known to make the potent icthyotoxin euglenophycin.
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Two life support systems (a nitrifying trickle filter system and the single-celled algae Euglena gracilis) within the satellite will be used for producing biomass out of artificial urine in a closed system. Furthermore, the algae Euglena gracilis will protect the biosystem against high levels of ammonia present in urine.
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Paramylon is a carbohydrate similar to starch. The chloroplasts found in Euglena contain chlorophyll which aids in the synthesis of carbohydrates to be stored as starch granules and paramylon. Paramylon is made in the pyrenoids of Euglena. The euglenoids have chlorophylls a and b and they store their photosynthate in an unusual form called paramylon starch, a β-1,3 polymer of glucose.
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Peranema, as drawn by William Saville-Kent in 1880 When Dujardin created the genus Peranema in 1841, he was unable to detect the second flagellum and classified it with other ostensibly uniflagellate "Eugléniens," Astasia and Euglena. In 1881 Georg Klebs drew a taxonomical distinction between colorless uniflagellates that live by phagotrophy (Peranema and Astasia) and the green uniflagellates that photosynthesize (Euglena). This distinction was generally abandoned after the publication, in 1952, of a major revision of the Euglenoids. In 1997, a combined morphological and molecular analysis of certain Euglenoids identified Peranama trichophorum, Euglena gracilis and Khawkinea quartana as a distinct monophyletic lineage, with P. trichophorum basal to the other two species.
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Berkelic acid is a fungal isolate with anticancer activity in vitro. It was first discovered in the fungal species Euglena Mutabilis, which evolved to live in the Berkeley Pit.
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Spliced leaders have been seen in trypanosomatids, Euglena, flatworms, Caenorhabditis. Some species contain only one spliced leader sequence found on all mRNAs. In C. elegans two are seen and are labeled SL1 and SL2.
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The unicellular alga Euglena gracilis converts exogenous tryptophol to two major metabolites: tryptophol galactoside and an unknown compound (a tryptophol ester), and to minor amounts of indole-3-acetic acid, tryptophol acetate, and tryptophol glucoside.
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Twintrons were discovered by Donald W. Copertino and Richard B. Hallick as a group II intron within another group II intron in Euglena chloroplast genome. They found that splicing of both the internal and external introns occurs via lariat intermediates. Additionally, twintron splicing was found to proceed by a sequential pathway, the internal intron being removed prior to the excision of the external intron. Since the original discovery, there have been other reports of Group III twintrons and GroupII/III twintrons in the chloroplast of Euglena gracilis.
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Microalgae have gained attention in recent years due to several reasons including their greater sensitivity to pollutants than many other organisms. In addition, they occur abundantly in nature, they are an essential component in very many food webs, they are easy to culture and to use in assays and there are few if any ethical issues involved in their use. Gravitactic mechanism of the microalgae Euglena gracilis (A) in the absence and (B) in the presence of pollutants. Euglena gracilis is a motile, freshwater, photosynthetic flagellate.
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The periplast is one of three types of cell-covering of three classes of algae. The Cryptomonads have the periplast covering. The Dinophyceae have a type called the amphiesma, and the Euglena covering is the pellicle.
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Euglena gracilis is a freshwater species of single-celled alga in the genus Euglena. It has secondary chloroplasts, and is a mixotroph able to feed by photosynthesis or phagocytosis. It has a highly flexible cell surface, allowing it to change shape from a thin cell up to 100 µm long, to a sphere of approximately 20 µm. Each cell has two flagella, only one of which emerges from the flagellar pocket (reservoir) in the anterior of the cell, and can move by swimming, or by so-called "euglenoid" movement across surfaces.
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The paramylon is stored in rod like bodies throughout the cytoplasm, called paramylon bodies, which are often visible as colorless or white particles in light microscopy. Their shape is often characteristic of the Euglena species that produces them.
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Dictyostelium cells and neutrophils can also swim, using a similar mechanism as for crawling. Another unicellular form of movement shown in Euglena is known as metaboly. The basis of sol gel theory is interconversion of sol and gel.
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Protist species used include Euglena gracilis (photosynthetic, green) and Physarum polycephalum (yellow-green). A technique called "bacteriography" involves selectively killing certain areas of a bacterial culture with radiation, in order to produce artistic patterns. After incubation, the culture is sealed with acrylic.
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Jane Elizabeth Parker was born in 1960 in Great Britain and completed her undergraduate degree at the University of Bradford in applied Biology in 1983. She went on to earn her PhD in 1986 from Swansea University on protein synthesis in Euglena.
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C. Barnes. The effect of heavy water of low concentration on Euglena. Science 79, 370 (1934) and then again in 1970sV. I. Lobyshev et al. Activation of Na,K-ATPasa by low concentration of D2O and inhibition by high concentrations, Biofizika 23, 397 (1978)V.
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The fluids are monitored with seven electrodes to measure ammonium, nitrite, nitrate, pH, chloride, sodium, and potassium. To monitor the health of Euglena gracilis, the system also analyse the microbes' mRNA to determine which proteins —and therefore which genes— are being commanded into action.
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Bracher studied Euglena Rose Bracher (1894 - 15 July 1941) was a British botanist and academic. She researched the ecology of the mud flats of the River Avon at Bristol and in particular the genus Euglena. Bracher was born in Salisbury and obtained a B.Sc. in 1917, followed by an M.Sc. in 1918 and a Ph.D. in 1927, all from the University of Bristol. She worked as a demonstrator at the London School of Medicine for Women (1918-1920), was a lecturer at the East London College (1921-1924), and took up a post of lecturer at the University of Bristol in 1924 which she held until her death in 1941.
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In most such organisms, one or more flagella are located at or near the anterior of the cell, e.g., Euglena. Often there is one directed forwards and one trailing behind. Among animals, fungi, which are part of a group called the opisthokonts, there is a single posterior flagellum.
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The most critical eyespot proteins are the photoreceptor proteins that sense light. The photoreceptors found in unicellular organisms fall into two main groups: flavoproteins and retinylidene proteins (rhodopsins). Flavoproteins are characterized by containing flavin molecules as chromophores, whereas retinylidene proteins contain retinal. The photoreceptor protein in Euglena is likely a flavoprotein.
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Under the light microscope, eyespots appear as dark, orange-reddish spots or stigmata. They get their color from carotenoid pigments contained in bodies called pigment granules. The photoreceptors are found in the plasma membrane overlaying the pigmented bodies. The eyespot apparatus of Euglena comprises the paraflagellar body connecting the eyespot to the flagellum.
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Binary fission in organisms can occur in four ways, irregular, longitudinal, transverse, oblique.i.e.left oblique & right oblique # Irregular: In this fission, cytokinesis may take place along any plane but it is always perpendicular to the plane of karyokinesis. e.g. amoeba # Longitudinal: Here cytokinesis takes place along the longitudinal axis. e.g. in flagellates like Euglena.
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In 1993 a new type of complex twintron composed of four individual group III introns has been characterized. The external intron was interrupted by an internal intron containing two additional introns. In 1995 scientists discovered the first non-Euglena twintron in cryptomonad alga Pyrenomonas salina. In 2004, several twintrons were discovered in Drosophila.
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It can be seen in many microorganisms including Euglena. The response of planktonic larvae of Lithodes aequispinus (king crab) to gravity is another example of gravitaxis. They show both positive and negative gravitaxes in a way that they move either upward (negative) or downward (positive). Gravitaxis can also be observed in Drosophila.
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This is analogous to positive chemotaxis except that the attractant is light rather than a chemical. Phototactic responses are observed in many organisms such as Serratia marcescens, Tetrahymena, and Euglena. Each organism has its own specific biological cause for a phototactic response, many of which are incidental and serve no end purpose.
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Automatic bioassay is possible, using the flagellate Euglena gracilis in a device which measures their motility at different dilutions of the possibly polluted water sample, to determine the EC50 (the concentration of sample which affects 50 percent of organisms) and the G-value (lowest dilution factor at which no-significant toxic effect can be measured).
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Her thesis was An Unusual Pattern of Thymidine Incorporation in Euglena. In 1966 she moved to Boston University, where she taught biology for twenty-two years. She was initially an Adjunct Assistant Professor, then was appointed to Assistant Professor in 1967. She was promoted to Associate Professor in 1971, to full Professor in 1977, and to University Professor in 1986.
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The Euglena photoreceptor was identified as a blue-light-activated adenylyl cyclase. Excitation of this receptor protein results in the formation of cyclic adenosine monophosphate (cAMP) as a second messenger. Chemical signal transduction ultimately triggers changes in flagellar beat patterns and cell movement. The archaeal-type rhodopsins of Chlamydomonas contain an all-trans retinylidene chromatophore which undergoes photoisomerization to a 13-cis isomer.
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Green algae have been taken up by the euglenids, chlorarachniophytes, a lineage of dinoflagellates, and possibly the ancestor of the CASH lineage (cryptomonads, alveolates, stramenopiles and haptophytes) in three or four separate engulfments. Many green algal derived chloroplasts contain pyrenoids, but unlike chloroplasts in their green algal ancestors, storage product collects in granules outside the chloroplast. Euglena, a euglenophyte, contains secondary chloroplasts from green algae.
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Zablen et al.’s phylogenetic analysis conducted electrophoresis on chloroplast ribosomal RNA, specifically on the 16S rRNA of Euglena gracilis. In conducting this experiment, researchers compared the electrophoretic fingerprint of this RNA to other chloroplasts and prokarya. In comparing these results, it was found that generally, these chloroplasts show a close genomic relationship, while a more distant one is seen for algae, and subsequently prokaryotic organisms.
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Kiss received his Bachelor of Science degree in biology from Georgetown University. He received his Ph.D. in botany and plant physiology from Rutgers University in 1987. His doctoral work focused on biosynthesis of the storage carbohydrate paramylon in the alga Euglena. Kiss did post-doctoral work (1987–90) on gravitropism in plants at Ohio State University, where he was first introduced to NASA-related research.
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Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) is a life science satellite developed by the German Aerospace Center (DLR) and is intended to investigate the possibility of growing plants (specifically tomatoes) in different levels of gravity, such as on the Moon and Mars, as a sustainable food source while using human urine for moisture and as the source of fixed nitrogen.
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Li was educated at Anhui Agricultural University in China where he was award a Bachelor's degree in Agronomy in 1982. He continued his education in the United States where he was awarded a PhD in 1991 from Brandeis University for his research into the enzymes involved in the reduction of sulfate (ATP sulfurylase and adenosine 5'-phosphosulfate sulfotransferase) in the single-celled organism Euglena.
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77 About 600 species of planktonic algae are known in the Sea of Azov.Kostianoy, p. 76 The number of species is dominated by diatoms and green algae; blue-green algae and pyrophites are significant, and euglena and yellow-green algae form only 5% of the species. Green algae are mostly responsible for the colour of the sea in the satellite images (see photos above).
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In an ecological context, phototrophs are often the food source for neighboring heterotrophic life. In terrestrial environments, plants are the predominant variety, while aquatic environments include a range of phototrophic organisms such as algae (e.g., kelp), other protists (such as euglena), phytoplankton, and bacteria (such as cyanobacteria). The depth to which sunlight or artificial light can penetrate into water, so that photosynthesis may occur, is known as the photic zone.
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The stigma (2) of the euglena hides a light-sensitive spot. The earliest predecessors of the eye were photoreceptor proteins that sense light, found even in unicellular organisms, called "eyespots". Eyespots can sense only ambient brightness: they can distinguish light from dark, sufficient for photoperiodism and daily synchronization of circadian rhythms. They are insufficient for vision, as they cannot distinguish shapes or determine the direction light is coming from.
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Euglena mutabilis, a photosynthetic flagellate Of eukaryotic groups, the protists are most commonly unicellular and microscopic. This is a highly diverse group of organisms that are not easy to classify. Several algae species are multicellular protists, and slime molds have unique life cycles that involve switching between unicellular, colonial, and multicellular forms. The number of species of protists is unknown since only a small proportion has been identified.
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During this process, acetyl-CoA and water are used as substrates. As a result, the cell does not lose 2 molecules of carbon dioxide as it does in the Krebs cycle. The glyoxylate cycle, facilitated by malate synthase and isocitrate lyase, allows plants and bacteria to subsist on acetyl-CoA or other two carbon compounds. For example, Euglena gracilis, a single-celled eukaryotic alga, consumes ethanol to form acetyl-CoA and subsequently, carbohydrates.
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Although Euglena is rather tolerant to acidity, it responds rapidly and sensitively to environmental stresses such as heavy metals or inorganic and organic compounds. Typical responses are the inhibition of movement and a change of orientation parameters. Moreover, this organism is very easy to handle and grow, making it a very useful tool for eco-toxicological assessments. One very useful particularity of this organism is gravitactic orientation, which is very sensitive to pollutants.
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The Nobel Prize in Physiology or Medicine 1905 Nobelprize.org Accessed 22 November 2006. Although these postulates cannot be applied in all cases, they do retain historical importance to the development of scientific thought and are still being used today. The discovery of microorganisms such as Euglena that did not fit into either the animal or plant kingdoms, since they were photosynthetic like plants, but motile like animals, led to the naming of a third kingdom in the 1860s.
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Peranema is a genus of free-living phagotrophic euglenids (Euglenida; Euglenozoa; Excavata). There are more than 20 nominal species, varying in size between 8 and 200 micrometers. Peranema cells are gliding flagellates found in freshwater lakes, ponds and ditches, and are often abundant at the bottom of stagnant pools rich in decaying organic material. Although they belong to the class Euglenoidea, and are morphologically similar to the green Euglena, Peranema have no chloroplasts, and do not conduct autotrophy.
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Eyespots are found in nearly all major animal groups, and are common among unicellular organisms, including euglena. The euglena's eyespot, called a stigma, is located at its anterior end. It is a small splotch of red pigment which shades a collection of light sensitive crystals. Together with the leading flagellum, the eyespot allows the organism to move in response to light, often toward the light to assist in photosynthesis, and to predict day and night, the primary function of circadian rhythms.
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The term protista was first used by Ernst Haeckel in 1866. Protists were traditionally subdivided into several groups based on similarities to the "higher" kingdoms such as: ;Protozoa: These unicellular "animal-like" (heterotrophic, and sometimes parasitic) organisms are further sub-divided based on characteristics such as motility, such as the (flagellated) Flagellata, the (ciliated) Ciliophora, the (phagocytic) amoeba, and the (spore-forming) Sporozoa. ;Protophyta: These "plant-like" (autotrophic) organisms are composed mostly of unicellular algae. The dinoflagelates, diatoms and Euglena-like flagellates are photosynthetic protists.
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Ehrenberg was appointed professor of medicine at Berlin University in 1827. In 1829 he accompanied Humboldt through eastern Russia to the Chinese frontier. After his return he began to concentrate his studies on microscopic organisms, which until then had not been systematically studied. For nearly 30 years Ehrenberg examined samples of water, soil, sediment, blowing dust and rock and described thousands of new species, among them well-known flagellates such as Euglena, ciliates such as Paramecium aurelia and Paramecium caudatum, and many fossils, in nearly 400 scientific publications.
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This elicits a positive photophobotactic response where the protobacteria moves towards blue and near-UV light. While the phobic response is classified as a photophobotactic response, the photochemical product of ferric complex in medium acts as a chemical stimulus, making this an example of chemotaxis as well. In the eukaryote Euglena, positive phototaxis and positive phobotaxis exhibit nearly the same action spectra, providing more evidence for their association. There also exists evidence to support photophobotaxis being coupled with electron transport needed in photosynthesis for two specific algaes: Phormidium uncinatum and Ph. autumnale.
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Osmotrophic euglenids are euglenids which have undergone osmotrophy. Due to a lack of characteristics that are useful for taxonomical purposes, the origin of osmotrophic euglenids is unclear, though certain morphological characteristics reveal a small fraction of osmotrophic euglenids is derived from phototrophic and phagotrophic ancestors. A prolonged absence of light or exposure to harmful chemicals may cause atrophy and absorption of the chloroplasts without otherwise harming the organism. A number of species exists where a chloroplast's absence was formerly marked with separate genera such as Astasia (colourless Euglena) and Hyalophacus (colourless Phacus).
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Haffkine began his scientific career as a protozoologist and protistologist, under the tutelage of Ilya Mechnikov at Imperial Novorossiya University in Odessa and later at the Pasteur Institute in Paris. p. 164–165 His early research was on protists such as Astasia, Euglena, and Paramecium, as well as the earliest studies on Holospora, a bacterial parasite of Paramecium. In the early 1890s, Haffkine shifted his attention to studies in practical bacteriology. The euglenid genus Khawkinea is named in honor of Haffkine's early studies of euglenids, first published in French journals with the author name translated from cyrillic as "Mardochée- Woldemar Khawkine".
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She joined the University of Wisconsin to study biology under Hans Ris and Walter Plaut, her supervisor, and graduated in 1960 with an MS in genetics and zoology. (Her first publication was with Plaut, on the genetics of Euglena, published in 1958 in the Journal of Protozoology.) She then pursued research at the University of California, Berkeley, under the zoologist Max Alfert. Before she could complete her dissertation, she was offered research associateship and then lectureship at Brandeis University in Massachusetts in 1964. It was while working there that she obtained her PhD from the University of California, Berkeley in 1965.
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Many species of Phacus are considered to be euplanktonic (free-floating organisms or open water plankton) because they are commonly found together with other genera of Euglenophyta. These species include members of the genera Lepocinclis, Trachelomonas, Euglena, and many different kinds of algae, which are typically found in similar aquatic habitats. The planktonic environments Phacus are generally found include swamps, ditches, trenches, ponds and even in many rice fields throughout North America and around the world. They are a small part of phytoplankton communities, but do serve important purposes such as nutrient cycling and food web stability.
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A protozoan species, Euglena mutabilis, was found to reside in the pit by Andrea A. Stierle and Donald B. Stierle, and the protozoans have been found to have adapted to the harsh conditions of the water. Intense competition for the limited resources caused these species to evolve the production of highly toxic compounds to improve survivability; natural products such as Berkeleydione, berkeleytrione, and Berkelic acid have been isolated from these organisms which show selective activity against cancer cell lines. Some of these species ingest metals and are being investigated as an alternative means of cleaning the water.
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Adenylyl cyclases are often activated or inhibited by G proteins, which are coupled to membrane receptors and thus can respond to hormonal or other stimuli. Following activation of adenylyl cyclase, the resulting cAMP acts as a second messenger by interacting with and regulating other proteins such as protein kinase A and cyclic nucleotide-gated ion channels. Photoactivated adenylyl cyclase (PAC) was discovered in Euglena gracilis and can be expressed in other organisms through genetic manipulation. Shining blue light on a cell containing PAC activates it and abruptly increases the rate of conversion of ATP to cAMP.
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Usually such organisms are planktonic (free-swimming) protists, and are nearly always viewed on microscope slides, where they appear essentially two-dimensional. In some cases a third axis can be defined, particularly where a non-terminal cytostome or other unique structure is present. Some elongated protists have distinctive ends of the body. In such organisms, the end with a mouth (or equivalent structure, such as the cytostome in Paramecium or Stentor), or the end that usually points in the direction of the organism's locomotion (such as the end with the flagellum in Euglena), is normally designated as the anterior end.
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Microbes then use nitrite () to convert the harmful ammonia () into nitrate (), which is then added to six tomato seeds as liquid fertiliser. In addition, the system incorporates a colony of the single-cell microorganism Euglena gracilis, which is a photosynthetic algae able to produce oxygen and biomass while protecting the whole system against high ammonia concentrations. This oxygen is necessary for the conversion of urine to nitrate until the photosynthetic oxygen production by the tomatoes is sufficient. Initially, the spacecraft will replicate lunar gravity on one greenhouse for a period of six months before simulating Martian gravity on the second greenhouse for the next six months.
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In Euglena gracilis, the rate of swimming has been shown to speed up with increased light intensity until the light reaches a certain saturation level, beyond which the swimming rate declines. The sea slug Discodoris boholiensis also displays positive photokinesis; it is nocturnal and moves slowly at night, but much faster when caught in the open during daylight hours. Moving faster in the exposed environment should reduce predation and enable it to conceal itself as soon as possible, but its brain is quite incapable of working this out. Photokinesis is common in tunicate larvae, which accumulate in areas with low light intensity just before settlement, and the behaviour is also present in juvenile fish such as sockeye salmon smolts.
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The genus was first established by the French biologist Felix Dujardin in 1841. Dujardin first published collective findings of the genus in the scientific journal Histoire naturelle des Zoophytes, Infusoires in 1841, separating them from the genus Euglena. The reason behind the separation was in order to create a group that correctly organizes their established morphological characteristics such as their rigid, flat, leaf-shape and small discoid chloroplasts with absent pyrenoids. Christian Ehrenberg was one of the first scientists to discover and classify members of the genus; his discovery of Phacus longicauda (Ehrenberg) was one of the first species of the genus to be discovered (1830) and was used as the holotype species when describing the genus.
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Ehrenberg, Hubner, Dujardin, and Klebs were some of the earliest researchers of Phacus, but they all had different diagnostic criteria when classifying these organisms. Originally, Ehrenberg tried to classify three species he discovered as Euglena because of their color, but ultimately were moved to the genus Phacus by Dujardin due to the similarity they exhibited in other more prominent morphological characteristics such as shape and strip arrangement. Since the establishment of the genus, there has been difficulty in classifying organisms due to morphology because many species of Phacus have physiological traits that closely resemble other related genera. Even the most minor difference in certain physiological properties caused great confusion in determining the proper classification for many species.
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The majority of these twintrons have been characterized within the Euglena chloroplast genome but these elements have also been found in cryptomonad algae (Pyrenomonas salina), and group I intron based twintrons (group I inserted within a group I intron) have been described in Didymium iridis. Since the discovery of the psbF twintron, several categories of twintrons have been characterized. A twintron can be simple (external intron interrupted by 1 internal intron), or complex (external intron interrupted by multiple internal introns). Most probably, the internal and external introns comprising the twintron element are from the same category; group I internal to group I, group II internal to group II, and group III internal to group III.
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Schematic representation of a Euglena cell with red eyespot (9) Schematic representation of a Chlamydomonas cell with chloroplast eyespot (4) The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids. It allows the cells to sense light direction and intensity and respond to it, prompting the organism to either swim towards the light (positive phototaxis), or away from it (negative phototaxis). A related response ("photoshock" or photophobic response) occurs when cells are briefly exposed to high light intensity, causing the cell to stop, briefly swim backwards, then change swimming direction. Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis.
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Spirillum bacteria have helical bodies with flagella at either end, and they spin about the central axis of their bodies as they move through the water. Archaea, a group of prokaryotes separate from bacteria, also feature flagella – known as archaella – driven by rotary motor proteins, which are structurally and evolutionarily distinct from bacterial flagella: whereas bacterial flagella evolved from the bacterial Type III secretion system, archaella appear to have evolved from type IV pili. Some eukaryotic cells, such as the protist Euglena and animal sperm, possess a convergent, evolutionary distinct flagellum-like structure known as a cilium or undulipodium. Unlike bacterial flagella, these structures do not rotate at the base; rather, they bend in such a way that the tip whips in a circle.
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Mixed twintrons (consisting of introns belonging to different categories) were characterized from the Euglena gracilis rps3 gene in which an internal group II intron is found to interrupt an external group III intron. In Rhodomonas salina (=Pyrenomonas salina) twintrons (nested group II/group III introns) were identified where the internal intron lost its splicing capacity, essentially merging with the outer intron forming one splicing unit. Recently, two novel twintrons have been uncovered within the fungal mitochondrial genome, one at position mS917 of the Cryphonectria parasitica mt-rns gene, where a group ID intron encoding a LAGLIDADG ORF invaded another ORF-less group ID intron. Another twintron complex was detected at position mS1247 of the Chaetomium thermophilumhere mt-rns gene, a group IIA1 intron invaded the open reading frame embedded within a group IC2 intron.
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Clockwise from top left: Blepharisma japonicum, a ciliate; Giardia muris, a parasitic flagellate; Centropyxis aculeata, a testate (shelled) amoeba; Peridinium willei, a dinoflagellate; Chaos carolinense, a naked amoebozoan; Desmerella moniliformis, a choanoflagellate Protozoa (also protozoan, plural protozoans) is an informal term for a group of single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris. Historically, protozoans were regarded as "one-celled animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. Although the traditional practice of grouping protozoa with animals is no longer considered valid, the term continues to be used in a loose way to describe single-celled protists (that is, eukaryotes that aren't animals, plants, or fungi) that feed by heterotrophy. Some examples of protozoa are Amoeba, Paramecium, Euglena and Trypanosoma.
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