Euglena's atypical respiratory chain adapts to the discoidal cristae and flexible metabolism

Euglena gracilis, a model organism of the eukaryotic supergroup Discoba harbouring also clinically important parasitic species, possesses diverse metabolic strategies and an atypical electron transport chain. While structures of the electron transport chain complexes and supercomplexes of most other eukaryotic clades have been reported, no similar structure is currently available for Discoba, limiting the understandings of its core metabolism and leaving a gap in the evolutionary tree of eukaryotic bioenergetics. Here, we report high-resolution cryo-EM structures of Euglena's respirasome I + III2 + IV and supercomplex III2 + IV2. A previously unreported fatty acid synthesis domain locates on the tip of complex I's peripheral arm, providing a clear picture of its atypical subunit composition identified previously. Individual complexes are re-arranged in the respirasome to adapt to the non-uniform membrane curvature of the discoidal cristae. Furthermore, Euglena's conformationally rigid complex I is deactivated by restricting ubiquinone's access to its substrate tunnel. Our findings provide structural insights for therapeutic developments against euglenozoan parasite infections.

Euglena gracilis (Euglena) powder supplementation enhanced immune function through natural killer cell activity in apparently healthy participants: A randomized, double-blind, placebo-controlled trial

Euglena gracilis (Euglena) is a microalgae found in most freshwater environments that produces paramylon, an insoluble β-1,3-glucan linked to human immunity. We hypothesized that Euglena powder has effects on immune function in apparently healthy adults. The study included male or female volunteers between the ages of 20 and 70 years who had white blood cell counts ranging from 4 × 103/µL to 10 × 103/µL, a "severe" rating on the stress questionnaire from the Korea National Health and Nutrition Examination Survey, and at least 2 upper respiratory infections with cold-like symptoms in the previous year. Participants received either a placebo or 700 mg of Euglena powder daily for 8 weeks. The study measured natural killer cell activity, cytokine concentrations, and blood lipid profiles to confirm the immune effect of Euglena consumption. In conclusion, Euglena improved immunological function through natural killer cell activity. Safety assessment showed no significant changes in vital signs or clinical chemistry indicators, and there were no adverse events associated with Euglena consumption. Euglena supplementation may help boost the immune systems of healthy individuals.

The potential of Euglena species as a bioindicator for soil ecotoxicity assessment

Currently, there are no standard international test methods for assessing aquatic and soil toxicity, with aquatic toxicity tests based on limited Euglena species. Here, we proposed Euglena species as extended test species, especially as new soil test species for a paper-disc soil method, considering its ecologically important roles in providing highly bioavailable in-vivo nutrients to upper trophic level organisms. We conducted experiments to identify the optimal exposure duration for two Euglena species (Euglena viridis and Euglena geniculata). We demonstrated the toxic effects of nickel (model contaminant) on their photosynthetic parameters and growth in freshwater. The growth and photosynthetic activity of three Euglena species were significantly inhibited in nickel-contaminated soil during paper-disc soil tests, especially the test species adsorbed onto paper-disc soil. Euglena gracilis was more sensitive to nickel than E. viridis and E. geniculata in freshwater and soil. Thus, E. viridis and E. geniculata have potential as additional test species for improving test species diversity, while all three species have potential as new soil test species for soil toxicity assessment. Thus, results these species may be suitable for routine aquatic toxicity testing and new soil toxicity testing, addressing the current paucity of test species in freshwater and soil toxicity assessment.

Biofuel production from Euglena: Current status and techno-economic perspectives

Sustainable aviation fuels (SAFs) can contribute reduce greenhouse gas emissions compared to conventional fuel. With the increasing SAFs demand, various generations of resources have been shifted from the 1st generation (oil crops), the 2nd generation (agricultural waste), to the 3rd generation (microalgae). Microalgae are the most suitable feedstock for jet biofuel production than other resources because of their productivity and capability to capture carbon dioxide. However, microalgae-based biofuel has a limitation of high freezing point. Recently, a jet biofuel derived from Euglena wax ester has been paying attention due to its low freezing point. Challenges still remain to enhance production yields in both upstream and downstream processes. Studies on downstream processes as well as techno-economic analysis on biofuel production using Euglena are highly limited to date. Economic aspects for the biofuel production will be ensured via valorization of industrial byproducts such as food wastes.

Biodiesel production from Custard apple seeds and Euglena Sanguinea using CaO nano-catalyst

This short communication investigated biodiesel production from Euglena Sanguineamicroalgaeand custard appleusing nano CaO as a heterogeneous catalyst. Different solvents were used to extract the oil at a fixed speed, time, and temperature for the samples to estimate the optimized oil yield%. The catalyst was synthesized by sol gel method in nano-scale. It was further characterized by FTIR spectroscopy, SEM, and XRD. The algal oil was pre-treated and trans-esterified with a catalyst to produce alkyl esters. The optimized process variables were determined using response surface methodology by varying parameters such as methanol to oil ratio and catalyst weight% for algal bio-oil and MeOH to oil ratio, time, and catalyst weight% for seed oil. The GC-MS was done to characterize the presence of biodiesel. Kinetic studies were done for the optimized condition for the algal oil and seed oil and it follows the pseudo-first order reaction.

Euglena extract suppresses adipocyte-differentiation in human adipose-derived stem cells

Euglena gracilis Z (Euglena) is a unicellular, photosynthesizing, microscopic green alga. It contains several nutrients such as vitamins, minerals, and unsaturated fatty acids. In this study, to verify the potential role of Euglena consumption on human health and obesity, we evaluated the effect of Euglena on human adipose-derived stem cells. We prepared a Euglena extract and evaluated its effect on cell growth and lipid accumulation, and found that cell growth was promoted by the addition of the Euglena extract. Interestingly, intracellular lipid accumulation was inhibited in a concentration-dependent manner. Quantitative real-time PCR analysis and western blotting analysis indicated that the Euglena extract suppressed adipocyte differentiation by inhibiting the gene expression of the master regulators peroxisome proliferator-activated receptor-γ (PPARγ) and one of three CCAAT-enhancer-binding proteins (C/EBPα). Further Oil Red O staining experiments indicated that the Euglena extract inhibited the early stage of adipocyte-differentiation. Consistent with these results, we observed that down-regulation of gene expression was involved in the early stage of adipogenesis represented by the sterol regulatory element binding protein 1 c (SREBP1c), two of three CCAAT-enhancer-binding proteins (C/EBPβ, C/EBPδ), and the cAMP regulatory element-binding protein (CREB). Taken together, these data suggest that Euglena extract is a promising candidate for the development of a new therapeutic treatment for obesity.

Growth studies on microalgae Euglena sanguinea in various natural eco-friendly composite media to optimize the lipid productivity

The environmental and culture conditions of a potential microalgae Euglena sanguinea were optimized for maximizing the biomass productivity. It was found that the organic macronutrient from poultry litter and organic micronutrient of seaweed extract are very effective to enhance the lipid production. Complementing, these organic nutrients with commercial NPK fertilizer, boost up the lipid productivity by 30.9% in comparison with the established standard Euglena medium. The fatty acid profile of the extracted oil by GC-MS reveals its conformity with commercial diesel.

Assessment of environmental variables in Cauvery River and its tributaries

This research paper pertains to the variation in water quality with special reference to physicochemical and biological parameters in Cauvery River and its tributaries in India over a period of 1 year. The quality of water in four streams of Cauvery River in Mysore, Mandya and Chamaraja Nagar districts, where many small scale sugar, paper industries and agricultural lands are located were analyzed. Sampling was carried out from Cauvery and its tributaries which were designated as stations 1, 2, 3 & 4 (all towards down streams of Cauvery River). The river water composition is increasingly dominated by PO4, NO3 Cl at stations 3 & 4 compared to stations 1 & 2. Significant spatial variations were observed in water level, transparency, turbidity, colour, DO, BOD, NO3, NO2 and total hardness among the physico-chemical parameters at the study locations. The DO level at stations 3 & 4 was lower than 5.0 mg/L, which is the recommended minimum allowable limit for aquatic life. 30 species of phytoplanktons were identified under five classes: viz, Chlorophyceae, Bacillariophyceae, Cyanophyceae, Euglenophyceae and Desmidaceae. About 20 algal species were recorded at station 1, 16 at station 2,13 species at station 3 and 14 species at station 4. The overall diversity and density of algae at four stations was significantly different. A posterior comparison revealed that stations 3 and 4 are the cause of significant difference. The chlorophyceae members, which dominated the algal community, were found to tolerate the effluent effect at stations land 2. Low algal diversity and negative impact on the biotic and abiotic environment were experienced at stations 3 and 4 throughout the duration of sampling, because of man made activities.

The application of Fresnel zone plate based projection in optofluidic microscopy

Optofluidic microscopy (OFM) is a novel technique for low-cost, high-resolution on-chip microscopy imaging. In this paper we report the use of the Fresnel zone plate (FZP) based projection in OFM as a cost-effective and compact means for projecting the transmission through an OFM's aperture array onto a sensor grid. We demonstrate this approach by employing a FZP (diameter = 255 microm, focal length = 800 microm) that has been patterned onto a glass slide to project the transmission from an array of apertures (diameter = 1 microm, separation = 10 microm) onto a CMOS sensor. We are able to resolve the contributions from 44 apertures on the sensor under the illumination from a HeNe laser (wavelength = 633 nm). The imaging quality of the FZP determines the effective field-of-view (related to the number of resolvable transmissions from apertures) but not the image resolution of such an OFM system--a key distinction from conventional microscope systems. We demonstrate the capability of the integrated system by flowing the protist Euglena gracilis across the aperture array microfluidically and performing OFM imaging of the samples.

Does consciousness really collapse the wave function? A possible objective biophysical resolution of the measurement problem

An analysis has been performed of the theories and postulates advanced by von Neumann, London and Bauer, and Wigner, concerning the role that consciousness might play in the collapse of the wave function, which has become known as the measurement problem. This reveals that an error may have been made by them in the area of biology and its interface with quantum mechanics when they called for the reduction of any superposition states in the brain through the mind or consciousness. Many years later Wigner changed his mind to reflect a simpler and more realistic objective position which appears to offer a way to resolve this issue. The argument is therefore made that the wave function of any superposed photon state or states is always objectively and stochastically changed within the complex architecture of the eye in a continuous linear process initially for most of the superposed photons, followed by a discontinuous nonlinear collapse process later for any remaining superposed photons, thereby guaranteeing that only final, measured information is presented to the brain, mind or consciousness. An experiment to be conducted in the near future may enable us to simultaneously resolve the measurement problem and also determine if the linear nature of quantum mechanics is violated by the perceptual process.

Ecological effects of various toxic agents on the aquatic microcosm in comparison with acute ionizing radiation

The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of gamma-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation.

FOLIC ACID AND VITAMIN B12 LEVELS IN PREGNANCY AND THEIR RELATION TO MEGALOBLASTIC ANAEMIA

There is a significant fall in the serum folic acid level during pregnancy, reaching its lowest level at term. This is most pronounced in twin pregnancies. A similar but less spectacular fall occurs in the vitamin B(12) concentration. In megaloblastic anaemia both folic acid and vitamin B(12) levels are lower than in other pregnant women. The degree of megaloblastic change in the bone marrow, as measured by the type and number of megaloblasts, is reflected in the vitamin levels, cases with florid megaloblastosis showing the most marked depression of vitamin B(12) and folic acid activity. Although there is a significant difference in the mean folic acid levels between megaloblastic and normoblastic pregnant women, a considerable overlap exists between individual values in the two groups. When the labile folic-acid factor is determined separately the test becomes much more specific. In the present series, all cases of megaloblastic anaemia yielded labile-factor levels below 1.0 mmug. per ml., while a similar value was encountered in only one of 35 normal pregnancies. In five women with megaloblastic anaemia the vitamin B(12) concentration was less than 100 mumug. per ml. but rose to normal levels on folic acid therapy alone.

AMINO ACID COMPOSITION OF BULK PROTEIN OF EUGLENA GROWN IN WASTE WATER

The amino acid content of bulk protein in a sewage-grown Euglena sp. was examined. Concentrations of the essential amino acids, threonine, histidine, tryptophan, and valine, were similar to those found in other algae. The concentration of alanine was much higher. Methionine was not found at all, proline only in traces, and other amino acids at low concentrations. These results indicate that the amino acid content of bulk protein of the species of Euglena studied resembles that of plants far more closely than that of animals.

PLASTIDS AND MITOCHONDRIA: INHERITABLE SYSTEMS

Evidence has been cited which indicates that RNA and DNA are present in plastids and mitochondria. A multigenic apparatus in the plastid is deduced from the properties of bleached Euglena strains. Control mechanisms are present for the differentiation of proplastids to chloroplasts in Euglena and in higher plants, and for the differentiation of promitochondria to mitochondria in yeast. An operon-regulator mechanism for this control is suggested. A comparison of the hereditary cytoplasmic units of Euglena plastids and yeast mitochondria indicates cates great similarities in their properties. Because of these similarities in two unrelated organisms, we suggest that a DNA unit which is self-duplicating and which serves as a code for RNA is the basic hereditary unit of each plastid and mitochondrion. Much work must be done if this reasonable hypothesis is to be converted into well-founded theory. Some pressing problems await solution. We do not understand the nonrandom distribution of plastids in the mitotic divisions of variegated plants. A related unresolved problem is that of maternal inheritance, in which nonrandom segregation of cytoplasmic organelles occurs after fertilization, causing elimination of the organelles which are contributed by the male parent. How different are the gene components of one plastid in a cell from the gene components of other plastids in the same cell, and how do we test for these differences? Can gene exchange or recombination occur between organelles within the same cell? The answers to these questions may have to await development of more sophisticated techniques, such as the ability to transplant these organelles between different cells or to culture cellular organelles in vitro.