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Microorganisms have evolved sophisticated sensor-actuator circuits to perform taxis in response to various environmental stimuli. How any given circuit can select between different taxis responses in noisy vs. saturated stimuli conditions is unclear. Here, we investigate how Euglena gracilis can select between positive vs. negative phototaxis under low vs. high light intensities, respectively. We propose three general selection mechanisms for phototactic microswimmers, and biophysical modeling demonstrates their effectiveness. Perturbation and high-speed imaging experiments show that of these three mechanisms, the "photoresponse inversion mechanism" is implemented in E. gracilis: a fast, light-intensity-dependent switching between two flagellar beat states responsible for swimming and turning causes positive vs. negative phototaxis at low vs. high light intensity via run-and-tumble vs. helical klinotaxis strategies, respectively. This coordinated beat-switching mechanism then also accounts for a larger set of previously reported E. gracilis behaviors; furthermore, it suggests key design principles for other natural as well as synthetic microswimmers. [ABSTRACT FROM AUTHOR]

Natural konjac glucomannan is an ideal candidate for hydrogels due to its excellent gel‐forming abilities, though its limited nutritional value somewhat restricts its applications. This project primarily explored the thermal and rheological properties of composite hydrogels formed by combining konjac glucomannan with Euglena. The hydrogels were created using a Euglena suspension processed through hydration, high‐speed shearing, and ultrasonic homogenization. This is the first report to document the creation of composite gels using konjac glucomannan and Euglena. This novel combination enhanced the thermal stability of the gels to 258.7°C, improved frost resistance to −19.9°C, increased the maximum activation energy to 24,179.6 J/mol, and raised maximum creep compliance to 0.6259 1/Pa. These characteristics significantly expand their potential for food preservation and active nutrient delivery while also offering new strategy for developing nutritionally rich gel foods and new resource food matrices. [ABSTRACT FROM AUTHOR]

Background: Obesity, a global disease, can lead to different chronic diseases and a series of social health problems. Lifestyle changes, especially dietary changes, are the most effective way to treat obesity. Euglena, a novel food, has attracted much attention. Previous studies have shown that Euglena is an important modulator of the host immune response. In this study, the effects of Euglena as a nutritional intervention in high-fat-diet-induced obese C57BL/6J mice were investigated regarding adipose tissue accumulation and lipid and glucose metabolism by gavage at the dose of 100 mg/kg bodyweight for 9 weeks. This study is one of the few to investigate, in detail, the preventive effects of dietary Euglena on obesity. Methods: Five-week-old male C57BL/6J mice were fed with a high-fat diet (HFD) to induce obesity. An obesity model was created by feeding the high-fat diet for a period of 10 weeks. Obese mice were randomized into 2 groups with the same mean body weight, and no significant differences were observed between the groups: (1) the mice in the HEG group were maintained on a high-fat diet and daily gavaged with Euglena (100 mg/kg body weight) dissolved in saline (n = 7); and (2) the mice in the HFD group were maintained on a high-fat diet and daily gavaged with saline with the same volume (n = 7). The experiment finished after a nine-week period. Results: The results showed that Euglena could reduce the accumulation of white body fat, including subcutaneous fat and visceral fat, and mainly targeted subcutaneous fat. Euglena also reduced adipocyte particle size expansion, promoted lipolysis in adipose (adipose triglyceride lipase and hormone-sensitive triglyceride lipase) and liver tissue (reduced non-esterified fatty acid content), and improved obesity-induced ectopic fat deposition and glucose tolerance. Conclusions: Our findings suggest that Euglena, as a nutritional intervention in HFDs, efficiently reduces body weight and white adipose tissue deposition. The mechanism of Euglena is mainly though enhancing lipolysis. It is worth noting that Euglena β-glucan recovers the hyperglycemia and accumulation of ectopic fat within the liver induced by HFD. Our study is one of the few studies to report in detail the preventive effects of dietary Euglena on obesity in vivo. This study revealed that Euglena also has an important ameliorative effect on obesity and metabolic disorders, which laid a theoretical foundation for its future application in functional foods. [ABSTRACT FROM AUTHOR]

Euglena gracilis is a unique microalga that lacks a cell wall and is able to grow under different trophic culture conditions. In this study, cell growth, biomass production, and changes in the ultrastructure of E. gracilis cells cultivated photoautotrophically, mixotrophically, and under sequential-heterotrophy-photoinduction (SHP) were assessed. Mixotrophy induced the highest cell growth and biomass productivity (6.27 ± 0.59 mg/L/d) in E. gracilis, while the highest content of fatty acids, 2.69 ± 0.04% of dry cell weight (DCW) and amino acids, 38.16 ± 0.08% of DCW was obtained under SHP condition. E. gracilis also accumulated significantly higher saturated fatty acids and lower unsaturated fatty acids when cultivated under SHP condition. Transcriptomic analysis showed that the expression of photosynthetic genes (PsbA, PsbC, F-type ATPase alpha and beta) was lower, carbohydrate and protein synthetic genes (glnA, alg14 and fba) were expressed higher in SHP-culture cells when compared to other groups. Different trophic conditions also induced changes in the cell ultrastructure, where paramylon and starch granules were more abundant in SHP-cultured cells. The findings generated in this study illustrated that aerobic SHP cultivation of E. gracilis possesses great potential in human and animal feed applications. [ABSTRACT FROM AUTHOR]

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Euglena sp. is a unicellular, flagellated microalga considered one of the most promising microalgal feedstock species for biofuels. Reducing the level of liquid waste pollutants can be done biologically by using microalgal organisms. Its metabolites, including lipids, proteins, carbohydrates, and pigments, are appropriate for producing biorefinery products such as biodiesel and jet fuels. They can be isolated from extreme environments, such as highly acidic and ammonia-rich environments, that are not conducive to their proliferation. This study sought to determine the effect of the photoperiod or (light: dark) cycle (24 L:0 D, 12 L:12 D, 14 L:10 D, and 16 L:8 D) on the growth, biomass, metabolite content consisting of lipids, carbohydrates, and proteins, and the rate of CO 2 uptake by Euglena sp. As stated previously, the study was conducted by cultivating Euglena sp. on a laboratory scale with four photoperiod regimens. The results indicated that optimal growth, biomass content, and metabolite content were obtained with a 24 D:0 L lighting cycle. The control treatment (24 L: 0 D) had the highest biomass productivity (0.032 g.L-1.day-1 ± 0.004), lipid content (0.387 g.L-1 ± 0.031), protein content (0.542 mg.Ml-1 ± 0.007), carbohydrate content (0.409 x104 g.L-1), chlorophyll a (6.237 g.L-1 ± 0.184), chlorophyll b (2.838 g.L-1 ± 0.253), and total carotenoid (1.566 g.L-1 ± 0.105). Full light illumination (24 L:0 D) was significantly producing carotenoid content, including phaeophytin a, phaeophytin b, violaxanthin, 9'-cis-neoxanthin, dino xanthin, and fucoxanthin. [ABSTRACT FROM AUTHOR]

Calcium hypochlorite (Ca(ClO)2), which can be stably stored in powder form for a long period, is widely used as a disinfectant in various fields. A new sterilization process was developed in the present study, where a microalgal medium was sterilized using 0.02% Ca(ClO)2, followed by complete neutralization of the Ca(ClO)2 within 8 h through catalytic reaction of an MnCl2–Na2EDTA complex and a synergistic effect of glucose. When comparing the growth of Chlorella vulgaris in the autoclaved medium, a 2.65 times greater maximum cell growth was observed in cells grown in the medium prepared by treatment of Ca(ClO)2. This result indicates that denaturation of the medium by heat can hinder the growth of some microorganisms. In the case of cultivation of Euglena gracilis, successful culture growth was achieved without growth inhibition or contamination on a medium prepared in the same manner. [ABSTRACT FROM AUTHOR]

Influenza is an acute respiratory illness caused by influenza virus infection, which is managed using vaccines and antiviral drugs. Recently, the antiviral effects of plants and foods have gained attention. Euglena is a motile unicellular alga and eukaryotic photosynthetic microorganism. It has secondary chloroplasts and is a mixotroph able to feed by photosynthesis or phagocytosis. This review summarizes the influenza treatment effects of Euglena from the perspective of a functional food that is attracting attention. While it has been reported that Euglena contributes to suppressing blood sugar levels and ameliorates symptoms caused by stress by acting on the autonomic nervous system, the immunostimulatory and antiviral activities of Euglena have also been reported. In this review, I focused on the immunostimulation of antiviral activity via the intestinal environment and the suppression of viral replication in infected cells. The functions of specific components of Euglena, which also serves as the source of a wide range of nutrients such as vitamins, minerals, amino acids, unsaturated fatty acids, and β-1,3-glucan (paramylon), are also reviewed. Euglena has animal and plant properties and natural compounds with a wide range of functions, providing crucial information for improved antiviral strategies. [ABSTRACT FROM AUTHOR]

Mercury accumulation in the aquatic environment can be highly harmful. The body takes mercury vapor through the lungs, then absorbs mercury metal through the digestive system, and then the blood carries the metal to the brain. Bioremediation is the process of breaking down or converting harmful compounds into non-toxic forms, which can be accomplished through phytoremediation or phycoremediation. The goal of this study was to examine the growth and anatomy of Euglena sp. after being cultured in the mercurycontaining FWS-CW waste treatment system. The ability of Euglena sp. and Echinodorus palifolius to bioremediate mercury at different concentration as well as association and non-association treatments. This study was carried out in a bioreactor known as FSW-CW (Free Water Surface-Constructed Wetlands). Plant growth (plant height and number of leaves), chlorophyll content, diameter of root and petiole, metaxylem diameter of root, petiole, and leaves, cortical thickness of root and leaves, and petiole anatomy were all measured. Water temperature, pH, salinity, and light intensity were all measured as environmental parameters. Mercury treatment reduced Euglena density (183.5 cells. mL-1103 in control and 12.6 cells. mL-1103 in 100 ppm mercury treatment) and number of E. palifolius leaves, but not plant height and chlorophyll. Root and petiole diameters were affected by the mercury treatment, petiole diameter decreased unless the concentration was 100 ppm, whereas root diameter actually increased. The diameter of the root metaxylem increased, but the petioles and leaves, as well as the thickness of the root cortex, did not provide a significant response. The growth of E. palifolius was still optimal in the presence of Euglena in mercury-containing medium. [ABSTRACT FROM AUTHOR]

Recently, bioassay techniques have been gaining prominence in assessing water toxicity, offering comprehensive evaluations without identifying the individual chemical component. However, microscopic observation is a crucial component in microbioassays to know the critical features of the targeted microorganisms. However, as the microorganism’s size becomes smaller, observation becomes more difficult due to the narrower focal depth of the imaging system. To address this challenge, we propose a novel laser biospeckle non-imaging technique utilizing biospeckle patterns generated by microorganisms, enabling non-imaging assessments of their swimming ability. Paramecium and Euglena were used as microorganisms. Paramecium and Euglena were subjected to varying concentrations of heavy metal pollutants (Zn(NO3)2·6H2O and FeSO4·7H2O), and their swimming activity was quantified using a dynamic biospeckle analysis. The results show a concentration-dependent effect of Zn on both species, leading to decreased swimming ability at increased concentration. Conversely, Fe exhibited varying effects on Paramecia and Euglena, with the latter displaying tolerance at lower concentrations but a notable response at higher concentrations. The advantage of the method is that owing to the non-imaging system, an enormous number of microorganisms can be processed. Moreover, the method allows for an immediate and statistically significant estimation of their swimming ability in response to environmental pollution.

Photosynthetic organisms biosynthesize various carotenoids, a group of light-absorbing isoprenoid pigments that have key functions in photosynthesis, photoprotection, and phototaxis. Microalgae, in particular, contain diverse carotenoids and carotenoid biosynthetic pathways as a consequence of the various endosymbiotic events in their evolutionary history. Carotenoids such as astaxanthin, diadinoxanthin, and fucoxanthin are unique to algae. In microalgae, carotenoids are concentrated in the eyespot, a pigmented organelle that is important for phototaxis. A wide range of microalgae, including chlorophytes, euglenophytes, ochrophytes, and haptophytes, have an eyespot. In the chlorophyte Chlamydomonas reinhardtii, carotenoid layers in the eyespot reflect light to amplify the photosignal and shield photoreceptors from light, thereby enabling precise phototaxis. Our recent research revealed that, in contrast to the β-carotene-rich eyespot of C. reinhardtii, the euglenophyte Euglena gracilis relies on zeaxanthin for stable eyespot formation and phototaxis. In this review, we highlight recent advancements in the study of eyespot carotenoids and phototaxis in these microalgae, placing special emphasis on the diversity of carotenoid-dependent visual systems among microalgae.

An assessment of water quality in 8 urban lakes in South Tangerang City was conducted, as their condition was a concern. This research aims to assess water quality based on the condition of chemical-physical variables and phytoplankton composition. This research was conducted from late May to early October 2021 (the dry season until the inter-seasonal period). The Water Quality Index (WQI) ranged from 61.18-79.53 (medium-good). Phytoplankton composition consisted of 65 genera from 11 classes and 6 divisions. Oscillatoria, Euglena and Pediastrum were the dominant genera, meanwhile, Cyanophyceae and Chlorophyceae were the dominant class. Phytoplankton communities in all lakes were stable except RL and based on Jaccard index the value of inter-lakes show no identical similarities (1). In (Nygaard) values ranged from 2.50-undefined (slight-high eutrophication), and X (Saprobic indices) values ranged from 0.33-1.80 (very slight pollution-moderate pollution). The best correlations (both values were r = 0.53) in water quality between the variables were DO (ppm) and BOD (ppm) Urban lakes require further improvement in their lake management to be used as sources of drinking water. [ABSTRACT FROM AUTHOR]

Two-Photon Microscopy has become an invaluable tool for biological and medical research, providing high sensitivity, molecular specificity, inherent three-dimensional sub-cellular resolution and deep tissue penetration. In terms of imaging speeds, however, mechanical scanners still limit the acquisition rates to typically 10-100 frames per second. Here we present a high-speed non-linear microscope achieving kilohertz frame rates by employing pulse-modulated, rapidly wavelength-swept lasers and inertia-free beam steering through angular dispersion. In combination with a high bandwidth, single-photon sensitive detector, this enables recording of fluorescent lifetimes at speeds of 88 million pixels per second. We show high resolution, multi-modal - two-photon fluorescence and fluorescence lifetime (FLIM) - microscopy and imaging flow cytometry with a digitally reconfigurable laser, imaging system and data acquisition system. These high speeds should enable high-speed and high-throughput image-assisted cell sorting.

Euglenophyta are a group of algae that occur in water polluted by organic matter, which makes them a good indicator for organic pollution. This study aimed to determine the diversity of Euglenophyta, the environmental conditions favourable to their development and their implication in the sustainability and quality of the water in Loumbila reservoir. Algal and chemical water samples were collected monthly between January 2015 and June 2015. Phytoplankton species were identified under a light microscope using a Fuchs-Rosenthal chamber for algal cell counting. In total, 34 species of Euglenophyta were identified, four of which are new to the algal flora of Burkina Faso. The abundance and number of species of the genera Euglena and Phacus were significantly (p < 0.05) higher in the dry season. Euglena deses, Euglena texta, Euglena caudata, Phacus lefevrei, Phacus ranula and Phacus orbicularis were identified as indicator species of high nutrient concentration. The abundance of these genera was positively correlated with pH, dissolved oxygen, water transparency, conductivity, nitrates and orthophosphates. This study on the diversity of Euglenophyta enabled us to identify indicator species of reservoir pollution and the environmental factors favourable to their development. This can be used to guide the future water quality monitoring and management of the reservoir. [ABSTRACT FROM AUTHOR]

Eight species of Euglenophyceae from Surma river in Bangladesh are reported in this paper. The species are: Euglena hyalina Klebs, E. robertilamii Lefèvre, Phacus gigas Da Cunha, P. pseudoplatalea Pochm., P. triqueter (Ehr.)Duj. var. oblonga Shi, Trachelomonas scabra Playf. var. labiata (Teiling) H.-P., T. spiculifera Palmer, and T. umbilicopora Conradare. After a careful review on the list of euglenoid algae of Bangladesh, all these eight species are found to be new addition, and hitherto described here for the first time in Bangladesh. [ABSTRACT FROM AUTHOR]

The phylogeny of Euglenophyceae (Euglenozoa, Euglenida) has been discussed for decades with new genera being described in the last few years. In this study, we reconstruct a phylogeny using 18S rDNA sequence and structural data simultaneously. Using homology modeling, individual secondary structures were predicted. Sequence–structure data are encoded and automatically aligned. Here, we present a sequence–structure neighbor‐joining tree of more than 300 taxa classified as Euglenophyceae. Profile neighbor‐joining was used to resolve the basal branching pattern. Neighbor‐joining, maximum parsimony, and maximum likelihood analyses were performed using sequence–structure information for manually chosen subsets. All analyses supported the monophyly of Eutreptiella, Discoplastis, Lepocinclis, Strombomonas, Cryptoglena, Monomorphina, Euglenaria, and Colacium. Well‐supported topologies were generally consistent with previous studies using a combined dataset of genetic markers. Our study supports the simultaneous use of sequence and structural data to reconstruct more accurate and robust trees. The average bootstrap value is significantly higher than the average bootstrap value obtained from sequence‐only analyses, which is promising for resolving relationships between more closely related taxa. [ABSTRACT FROM AUTHOR]

Simple Summary: Considering the current challenges facing the modern livestock industry and the food insecurity situation, there is an urgent need to find alternative, sustainable, climate-friendly, and safe feed ingredients. This study provides a novel solution with the mixture of Euglena gracilis and Asparagopsis taxiformis as a feed for ruminants. Euglena gracilis is a highly nutritive material that can be used to partially replace the expensive, high-quality ingredients in the diet. Due to its bromoform content, Asparagopsis taxiformis is efficacious in reducing methane emissions. However, there are some health concerns for animals and humans with regard to its usage, as well as some doubts about the mass production that is required to achieve effective methane reduction. Therefore, the current study evaluated a new formulation composed of the minimum effective levels of Euglena and Asparagopsis to partially replace the concentrate mixture in the ruminant diet and reduce methane emissions. This combination had a synergistic effect in reducing methane production that was better than supplementing these algae individually and had no adverse impacts on animal productivity indices. Therefore, this intervention has double-sided benefits, providing high-quality alternative feed and reducing methane emissions with lower amounts of Asparagopsis. This study was conducted to provide alternative high-quality feed and to reduce methane production using a mixture of the minimum effective levels of Euglena gracilis, EG, and Asparagopsis taxiformis, AT. This study was performed as a 24 h in vitro batch culture. Chemical analysis demonstrated that EG is a highly nutritive material with 26.1% protein and 17.7% fat. The results showed that the supplementation of AT as a feed additive at 1 and 2.5% of the diet reduced methane production by 21 and 80%, respectively, while the inclusion of EG in the diet at 10 and 25% through partially replacing the concentrate mixture reduced methane production by 4 and 11%, respectively, with no adverse effects on fermentation parameters. The mixtures of AT 1% with both EG 10% and EG 25% had a greater reductive potential than the individual supplementation of these algae in decreasing methane yield by 29.9% and 40.0%, respectively, without adverse impacts on ruminal fermentation characteristics. These results revealed that the new feed formulation had a synergistic effect in reducing methane emissions. Thus, this approach could provide a new strategy for a sustainable animal production industry. [ABSTRACT FROM AUTHOR]

Influenza is an acute respiratory illness caused by influenza virus infection, which is managed using vaccines and antiviral drugs. Recently, the antiviral effects of plants and foods have gained attention. Euglena is a motile unicellular alga and eukaryotic photosynthetic microorganism. It has secondary chloroplasts and is a mixotroph able to feed by photosynthesis or phagocytosis. This review summarizes the influenza treatment effects of Euglena from the perspective of a functional food that is attracting attention. While it has been reported that Euglena contributes to suppressing blood sugar levels and ameliorates symptoms caused by stress by acting on the autonomic nervous system, the immunostimulatory and antiviral activities of Euglena have also been reported. In this review, I focused on the immunostimulation of antiviral activity via the intestinal environment and the suppression of viral replication in infected cells. The functions of specific components of Euglena, which also serves as the source of a wide range of nutrients such as vitamins, minerals, amino acids, unsaturated fatty acids, and β-1,3-glucan (paramylon), are also reviewed. Euglena has animal and plant properties and natural compounds with a wide range of functions, providing crucial information for improved antiviral strategies.

Microorganisms possess taxes, which are the behavioral response to stimuli. The interaction between taxis and fluid dynamic instability leads to a macroscopic flow called bioconvection. In this study, we demonstrated that an isolated, single, three-dimensional bioconvection cell can exist within Euglena suspension. The isolated convection cell was named a “bioconvection spot.” To reveal the formation of this bioconvection spot in a cylindrical container, position-control experiments were designed in a non-uniform light environment. Upon exposure of Euglena suspensions to varying light conditions with white and red regions, Euglena was determined to aggregate into the red (darker) region. This was attributed to its phototactic response of Euglena, causing its movement toward a darker environment and away from a strong light. Thus, the bioconvection spot was created by manipulating the local cell density of the suspension and the light environments. Using our experimental setup, we observed the structure of the spot and established that it radiated pulses of local cell densities of Euglena.

Cultivating microalgae as an alternative energy resource requires the optimization of the cultivation process. Euglena is a biofuel microalga with proteins, essential amino acids, vitamins C and E, lipids, beta carotene, and beta-1,3-glucan (paramylon). Light intensity and photoperiod are crucial factors in determining microalgae biomass production because of their relationship to maximum photosynthesis efficiency. As a result, optimising growth conditions in microalgae cultivation is critical for maximising productivity. This study looked at how different photoperiod treatments (12:12, 14:10, 16:8, 18:6, and 24:0 h) affected the growth, biomass, lipid, carbohydrates, and protein content of Euglena sp. cultures in a modified CM (Cramer-Myers) medium. The 18:6 photoperiod treatment produced the highest specific growth rate, biomass, lipid carbohydrate, and protein content, according to the study's findings. The biomass concentration was 0.4190.184 g/L, and the specific growth rate was 5.960.66 (OD680/OD680/hx10-3). The lipid concentration was 0.2030.078 g/L, the carbohydrate concentration was 378.061252.135 mg/mL, and the protein concentration was 371.142107.126 g/L. [ABSTRACT FROM AUTHOR]

Protein glycosylation, and in particular N -linked glycans, is a hallmark of eukaryotic cells and has been well-studied in mammalian cells and parasites. However, little research has been conducted to investigate the conservation and variation of protein glycosylation pathways in other eukaryotic organisms. Euglena gracilis is an industrially important microalga, used in the production of biofuels and nutritional supplements. It is evolutionarily highly divergent from green algae and more related to kinetoplastid pathogens. It was recently shown that E. gracilis possesses the machinery for producing a range of protein glycosylations and make simple N -glycans, but the modified proteins were not identified. This study identifies the glycosylated proteins, including transporters, extracellular proteases, and those involved in cell surface signalling. Notably, many of the most highly expressed and glycosylated proteins are not related to any known sequences and are, therefore, likely to be involved in important novel functions in Euglena. [ABSTRACT FROM AUTHOR]

Chloroplasts are cellular organelles specific to plants, containing pigments, including chlorophyll, necessary for photosynthesis. Our short paper is a discussion of cases of chloroplast-animal cell endosymbiosis, as well as the potential applications of chloroplast transfer to animals, something that has not yet been accomplished by the research groups involved in this challenge. [ABSTRACT FROM AUTHOR]

Human exploration of space and other celestial bodies bears a multitude of challenges. The Earth-bound supply of material and food is restricted, and in situ resource utilisation (ISRU) is a prerequisite. Excellent candidates for delivering several services are unicellular algae, such as the space-approved flagellate Euglena gracilis. This review summarizes the main characteristics of this unicellular organism. Euglena has been exposed on various platforms that alter the impact of gravity to analyse its corresponding gravity-dependent physiological and molecular genetic responses. The sensory transduction chain of gravitaxis in E. gracilis has been identified. The molecular gravi-(mechano-)receptors are mechanosensory calcium channels (TRP channels). The inward gated calcium binds specifically to one of several calmodulins (CaM.2), which, in turn, activates an adenylyl cyclase. This enzyme uses ATP to produce cAMP, which induces protein kinase A, followed by the phosphorylation of a motor protein in the flagellum, initiating a course correction, and, finally, resulting in gravitaxis. During long space missions, a considerable amount of food, oxygen, and water has to be carried, and the exhaled carbon dioxide has to be removed. In this context, E. gracilis is an excellent candidate for biological life support systems, since it produces oxygen by photosynthesis, takes up carbon dioxide, and is even edible. Various species and mutants of Euglena are utilized as a producer of commercial food items, as well as a source of medicines, as it produces a number of vitamins, contains numerous trace elements, and synthesizes dietary proteins, lipids, and the reserve molecule paramylon. Euglena has anti-inflammatory, -oxidant, and -obesity properties. [ABSTRACT FROM AUTHOR]

Cultured fat is an important component of cell-cultured meat, which furnishes essential fatty acids and phospholipids, as well as being abundant in cholesterol. However, few studies have been on regulating the nutritional composition of cell-cultured meat, especially concerning the deposition of polyunsaturated fatty acids (PUFAs) and cholesterol. Here, we use sodium alginate-gelatin scaffolds to generate cultured fat, and find that phosphatidylcholine (PC) can promote the adipogenic differentiation of fibro-adipogenic progenitors (FAPs), accelerate lipid accumulation, and facilitate cultured fat production in the sodium alginate-gelatin 3D culture system. Interestingly, when PC is loaded into Euglena (Eg-PC) for co-culture, the triglycerides (TGs) content in fat is further increased. Multi-omics analysis reveals that PC treatment significantly alters the lipid composition of cultured fat produced by FAPs and increases the content of TGs, especially PUFAs (alpha-linolenic acid and linolenic acid). More importantly, PC treatment also reduces the total cholesterol content of cultured fat. This study provides innovative approaches for producing cultured fat with "high PUFAs and low cholesterol". [Display omitted] • Production of cultured fat using sodium alginate-gelatin composite hydrogel system. • PC promotes the adipogenic differentiation of fibro-adipogenic progenitors (FAPs). • Euglena-PC enhances the efficiency of PC in regulating FAPs differentiation. • PC contributes to cultured meat production with "high PUFAs and low cholesterol". • PC decreases cholesterol deposition by regulating HIF1A-Insig2-HMGCR pathway. [ABSTRACT FROM AUTHOR]

The feasibility of preparing a novel wet‐spun multifilament derived from paramylon‐a linear β‐1,3‐glucan‐is investigated in this study. The decomposition temperature of the paramylon multifilament (∼300 °C) exceeds that of a wet‐spun cellulose one (∼270 °C). The distinctive feature of the paramylon multifilament is that its moisture regain is considerably higher than that of the cellulose multifilament (∼16 % vs ∼11 %). Scanning electron microscopy (SEM) observations of a homogenized aqueous dispersion containing paramylon multifilaments revealed that the shear‐force‐resistant and water‐insoluble fibrils detach from the paramylon multifilament, whereas the cellulose filament remains almost intact. SEM images provided two insights. First, the paramylon filament comprises many fibrils. Second, the adhesion between fibrils is susceptible to water molecules. The higher moisture regain is ascribable to this assembly architecture, i. e., the adhesion between the fibrils decreases upon exposure to moisture, which increases the surface area and fosters much more water absorption than that in the cellulose filament. [ABSTRACT FROM AUTHOR]

The following taxa belong to eight species under five genera of euglenoid algae, namely, Euglena anabaena Mainx., Phacus glaber Pochmann (Defl.) Posch, Phacus indicus Skvortzov, Protaspis obovata Skuja, Strombomonas lanceolata (Playfair) Deflandre, Trachelomonas hexangulata (Swir) Playf., T. obovata var. klebsiana Defl. and T. pseudocaudata Defl. are described here for the first time for Bangladesh. [ABSTRACT FROM AUTHOR]

Paramylon from Euglena gracilis is an insoluble crystalline β-1,3-glucan which have pharmaceutical and nutraceuticals applications. The present study aims to check the prebiotic potential of paramylon derived from heterotrophically grown E. gracilis in bioreactor. The Paramylon was extracted using sodium dodecyl sulfate from E. gracilis biomass. The Fourier Transform-Infra Red spectroscopy and scanning electron microscopy demonstrated the isolated paramylon to be equivalent to that of analytical standard. The prebiotic activity of E. gracilis cell extract and isolated paramylon was studied. E. gracilis cell extract as well as isolated paramylon led to cell number enhancement of Lacfid (Lactobacillus) strain exhibiting the prebiotic activities.

Summary: The coupling between mitochondrial respiration and photosynthesis plays an important role in the energetic physiology of green plants and some secondary‐red photosynthetic eukaryotes (diatoms), allowing an efficient CO2 assimilation and optimal growth.Using the flagellate Euglena gracilis, we first tested if photosynthesis–respiration coupling occurs in this species harbouring secondary green plastids (i.e. originated from an endosymbiosis between a green alga and a phagotrophic euglenozoan). Second, we tested how the trophic state (mixotrophy and photoautotrophy) of the cell alters the mechanisms involved in the photosynthesis–respiration coupling.Energetic coupling between photosynthesis and respiration was determined by testing the effect of respiratory inhibitors on photosynthesis, and measuring the simultaneous variation of photosynthesis and respiration rates as a function of temperature (i.e. thermal response curves). The mechanism involved in the photosynthesis–respiration coupling was assessed by combining proteomics, biophysical and cytological analyses.Our work shows that there is photosynthesis–respiration coupling and membrane contacts between mitochondria and chloroplasts in E. gracilis. However, whereas in mixotrophy adjustment of the chloroplast ATP/NADPH ratio drives the interaction, in photoautotrophy the coupling is conditioned by CO2 limitation and photorespiration. This indicates that maintenance of photosynthesis–respiration coupling, through plastic metabolic responses, is key to E. gracilis functioning under changing environmental conditions. [ABSTRACT FROM AUTHOR]

Summary: The eukaryotic flagellum/cilium is a prominent organelle with conserved structure and diverse functions. Euglena gracilis, a photosynthetic and highly adaptable protist, employs its flagella for both locomotion and environmental sensing.Using proteomics of isolated E. gracilis flagella we identify nearly 1700 protein groups, which challenges previous estimates of the protein complexity of motile eukaryotic flagella.We not only identified several unexpected similarities shared with mammalian flagella, including an entire glycolytic pathway and proteasome, but also document a vast array of flagella‐based signal transduction components that coordinate gravitaxis and phototactic motility. By contrast, the pellicle was found to consist of > 900 protein groups, containing additional structural and signalling components.Our data identify significant adaptations within the E. gracilis flagellum, many of which are clearly linked to the highly flexible lifestyle. [ABSTRACT FROM AUTHOR]

Abstract Background Global demand for energy is on the rise at a time when limited natural resources are fast depleting. To address this issue, microalgal biofuels are being recommended as a renewable and eco-friendly substitute for fossil fuels. Euglena gracilis is one such candidate that has received special interest due to their ability to synthesize wax esters that serve as precursors for production of drop-in jet fuel. However, to realize economic viability and achieve industrial-scale production, development of novel methods to characterize algal cells, evaluate its culture conditions, and construct appropriate genetically modified strains is necessary. Here, we report a Raman microspectroscopy-based method to visualize important metabolites such as paramylon and ester during wax ester fermentation in single Euglena gracilis cells in a label-free manner. Results We measured Raman spectra to obtain intracellular biomolecular information in Euglena under anaerobic condition. First, by univariate approach, we identified Raman markers corresponding to paramylon/esters and constructed their time-lapse chemical images. However, univariate analysis is severely limited in its ability to obtain detailed information as several molecules can contribute to a Raman band. Therefore, we further employed multivariate curve resolution analysis to obtain chain length-specific information and their abundance images of the produced esters. Accumulated esters in Euglena were particularly identified to be myristyl myristate (C28), a wax ester candidate suitable to prepare drop-in jet fuel. Interestingly, we found accumulation of two different forms of myristyl myristate for the first time in Euglena through our exploratory multivariate analysis. Conclusions We succeeded in visualizing molecular-specific information in Euglena during wax ester fermentation by Raman microspectroscopy. It is obvious from our results that simple univariate approach is insufficient and that multivariate curve resolution analysis is crucial to extract hidden information from Raman spectra. Even though we have not measured any mutants in this study, our approach is directly applicable to other systems and is expected to deepen the knowledge on lipid metabolism in microalgae, which eventually leads to new strategies that will help to enhance biofuel production efficiency in the future.

Euglena gracilis, a green microalga known as a potential candidate for jet fuel producers and new functional food resources, is highly tolerant to antibiotics, heavy metals, and other environmental stresses. Its cells contain many high-value products, including vitamins, amino acids, pigments, unsaturated fatty acids, and carbohydrate paramylon as metabolites, which change contents in response to various extracellular environments. However, mechanism insights into the cellular metabolic response of Euglena to different toxic chemicals and adverse environmental stresses were very limited. We extensively investigated the changes of cell biomass, pigments, lipids, and paramylon of E. gracilis under several environmental stresses, such as heavy metal CdCl2, antibiotics paromomycin, and nutrient deprivation. In addition, global metabolomics by Ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) was applied to study other metabolites and potential regulatory mechanisms behind the differential accumulation of major high-valued metabolites. This study collects a comprehensive update on the biology of E. gracilis for various metabolic responses to stress conditions, and it will be of great value for Euglena cultivation and high-value [154mm][10mm]Q7metabolite production.

The carotenoids, including lycopene, lutein, astaxanthin, and zeaxanthin belong to the isoprenoids, whose basic structure is made up of eight isoprene units, resulting in a C40 backbone, though some of them are only trace components in Euglena. They are essential to all photosynthetic organisms due to their superior photoprotective and antioxidant properties. Their dietary functions decrease the risk of breast, cervical, vaginal, and colorectal cancers and cardiovascular and eye diseases. Antioxidant functions of carotenoids are based on mechanisms such as quenching free radicals, mitigating damage from reactive oxidant species, and hindering lipid peroxidation. With the development of carotenoid studies, their distribution, functions, and composition have been identified in microalgae and higher plants. Although bleached or achlorophyllous mutants of Euglena were among the earliest carotenoid-related microalgae under investigation, current knowledge on the composition and biosynthesis of these compounds in Euglena is still elusive. This review aims to overview what is known about carotenoid metabolism in Euglena, focusing on the carotenoid distribution and structure, biosynthesis pathway, and accumulation in Euglena strains and mutants under environmental stresses and different culture conditions. Moreover, we also summarize the potential applications in therapy preventing carcinogenesis, cosmetic industries, food industries, and animal feed.

Euglenids have long been studied due to their unique physiology and versatile metabolism, providing underpinnings for much of our understanding of photosynthesis and biochemistry, and a growing opportunity in biotechnology. Until recently there has been a lack of genetic studies due to their large and complex genomes, but recently new technologies have begun to unveil their genetic capabilities. Whilst much research has focused on the model organism Euglena gracilis, other members of the euglenids have now started to receive due attention. Currently only poor nuclear genome assemblies of E. gracilis and Rhabdomonas costata are available, but there are many more plastid genome sequences and an increasing number of transcriptomes. As more assemblies become available, there are great opportunities to understand the fundamental biology of these organisms and to exploit them for biotechnology., Competing Interests: Declaration of interests The authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Lipopolysaccharide (LPS), an endotoxin, is known to induce inflammatory response and oxidative stress in rodents. We evaluated the protective role of Euglena tuba extract (ETME) against LPS induced inflammatory response and oxidative stress in male Balb/c mice. Male Balb/c mice were divided into 4 groups. Group 1 (control) were intraperitoneally administered 0.5 mL PBS. Group 2, 3 and 4 were treated with a single dose of LPS (i.p. 40 mg/kg body weight). Prior 1 h, Group 3 and 4 received orally 100 mg/kg body weight and 200 mg/kg body weight ETME respectively. Biomarkers of oxidative stress including TBARS, SOD, Catalase, Liver marker enzyme (SGPT and SGOT), Nitric Oxide, and inflammatory cytokines including IL-6 and TNF-α, were estimated in serum. Oxidative stress and inflammatory markers were significantly increased in the LPS treated group, whereas ETME treated group at different concentrations protected mice from pro inflammatory cytokines and oxidative stress. Our results indicate that 70% methanolic extract of Euglena tuba can efficiently counteract free radical generation and increased level of inflammatory cytokine in an LPS induced mice model. [ABSTRACT FROM AUTHOR]

Green euglenophytes are a group of eukaryotes with ancient origin. In order to understand the evolution of the group, it is interesting to know which characteristics are more primitive. Here, a phylogenetic tree of green euglenophytes based on the 18S rRNA gene was constructed, and ancestral states were reconstructed based on eight morphological characters. This research clarifies the phylogenetic relationships of green euglenophytes and provides a basis for the study of the origin of these plants. The phylogenetic tree, which was constructed by Bayesian inference, revealed that: Eutreptia and Eutreptiella were sister groups and that Lepocinclis, Phacus, and Discoplastis were close relatives; Euglena, Cryptoglena, Monomorphina, and Colacium were closely related in addition to Trachelomonas and Strombomonas; and Euglena was not monophyletic. An ancestral reconstruction based on morphological characters revealed seven primitive character states: ductile surface, spirally striated, slightly narrowing or sharp elongated cauda, absence of a lorica, chloroplast lamellar, shield or large discoid, pyrenoid with sheath, and with many small paramylon grains. However, the ancestral state of the length of the flagellum could not be inferred. Euglena and Euglenaria, which both possessed all of the ancestral character states, might represent the most ancient lineages of green euglenophytes. [ABSTRACT FROM AUTHOR]

An earlier proposal of euglenid affinity for the acritarch Moyeria was based primarily on the pattern of bi-helical striate ornamentation as seen in scanning electron microscopy and light microscopy. Examination of specimens using transmission electron microscopy reveals that the 'striae' are actually integral components of the microfossil wall itself, corresponding to the pellicle strips of some euglenid species today. A Silurian specimen from Scotland preserves an articulated wall composed of thickened arches and thinner U-shaped interconnecting segments paralleling that seen in some modern photosynthetic euglenids. A second specimen from the Moyeria holotype section (Silurian of New York State) shows fused articulation, again compatible with some extant euglenids. This evidence is sufficient to transfer Moyeria out of the Incertae sedis group, Acritarcha, and into the Euglenida. This proposal helps establish the morphological basis for the recognition of euglenid microfossils and ultimately provides evidence of a lengthy fossil record of the eukaryotic supergroup Excavata. [ABSTRACT FROM AUTHOR]

Asymmetrical flow field-flow fractionation (AF4) and high-resolution Orbitrap mass spectrometry (HRMS) were used to separate and characterize cellular fractions of the dark- and light-grown Euglena gracilis cellular material. Biological replicates analyzed by HRMS shared 21–73% of commonly detected m/z values. Greater variability in shared features was found in light-grown cellular fractions (p < 0.05), likely due to small variations in growth stage. Significant differences in molecular composition were observed between AF4 cellular fractions, with dark cell fractions showing a propensity towards carbohydrate-like and tannin-like compounds, and higher double-bond equivalent (DBE) and modified aromatic index (AImod) were associated with light-grown cell fractions. Fractionation and high-resolution mass spectrometry aided characterization demonstrated the power of the AF4 to selectively cater to certain compounds/cellular entities with distinct compositional classes and double-bond equivalents and aromaticity index characteristics. [ABSTRACT FROM AUTHOR]