The Mitochondrion

Buetow, D.E.

doi:10.1016/b978-0-12-139904-7.50009-9

Cited by 20 publications

(29 citation statements)

References 269 publications

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“…This is regarded as a general strategy employed by animals that accumulate opines (107,169). The temporary accumulation and reoxidation, rather than the excretion, of end products are also encountered during lactate fermentations in humans (194) and during wax ester fermentation in Euglena (62,514). In addition to opines, large amounts of alanine and succinate are produced.…”

Section: Animalsmentioning

confidence: 99%

“…Euglenids are a broad and diverse group containing many typical flagellate inhabitants of shallow freshwater environments, but relatives can also be found in anoxic marine (38, 129a) and anoxic freshwater (457a) ecosystems, whereby some members possess organelles ultrastructurally similar to hydrogenosomes (129a, 457a). Only one member of the euglenids has been extensively studied from a biochemical standpoint: Euglena gracilis (62). Grown aerobically, Euglena gracilis expresses pyruvate dehydrogenase (PDH) in mitochondria (196) and respires O 2 but by using a slightly modified Krebs cycle that is also found among some alphaproteobacteria (168).…”

Section: Fig 13mentioning

confidence: 99%

“…Grown aerobically, Euglena gracilis expresses pyruvate dehydrogenase (PDH) in mitochondria (196) and respires O 2 but by using a slightly modified Krebs cycle that is also found among some alphaproteobacteria (168). The shunt involves the replacement of ␣-ketoglutarate dehydrogenase by ␣-ketoglutarate decarboxylase and succinate semialdehyde dehydrogenase (62). When grown under anaerobic conditions (Fig.…”

Section: Fig 13mentioning

confidence: 99%

“…When grown under anaerobic conditions (Fig. 15), Euglena uses acetyl-CoA as the terminal electron acceptor and produces wax esters as end products of metabolism (62,(213)(214)(215)514).…”

Section: Fig 13mentioning

confidence: 99%

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Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

Müller

Mentel

Hellemond

et al. 2012

Microbiol Mol Biol Rev

695

904

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SUMMARY Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified.

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Section: Animalsmentioning

confidence: 99%

Section: Fig 13mentioning

confidence: 99%

Section: Fig 13mentioning

confidence: 99%

“…When grown under anaerobic conditions (Fig. 15), Euglena uses acetyl-CoA as the terminal electron acceptor and produces wax esters as end products of metabolism (62,(213)(214)(215)514).…”

Section: Fig 13mentioning

confidence: 99%

See 2 more Smart Citations

Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

Müller

Mentel

Hellemond

et al. 2012

Microbiol Mol Biol Rev

695

904

View full text Add to dashboard Cite

show abstract

“…2). Meanwhile, a number of the lineages lacking Min proteins are known to possess reticulate mitochondria in at least one tissue and during at least one life stage, including opisthokonts (77), plants (78,79), the euglenozoan Euglena gracilis (80), and apicomplexa (81,82) (Fig. 2).…”

Section: Resultsmentioning

confidence: 99%

An ancestral bacterial division system is widespread in eukaryotic mitochondria

Leger

Petrů

Žárský

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Bacterial division initiates at the site of a contractile Z-ring composed of polymerized FtsZ. The location of the Z-ring in the cell is controlled by a system of three mutually antagonistic proteins, MinC, MinD, and MinE. Plastid division is also known to be dependent on homologs of these proteins, derived from the ancestral cyanobacterial endosymbiont that gave rise to plastids. In contrast, the mitochondria of model systems such as Saccharomyces cerevisiae, mammals, and Arabidopsis thaliana seem to have replaced the ancestral α-proteobacterial Min-based division machinery with host-derived dynamin-related proteins that form outer contractile rings. Here, we show that the mitochondrial division system of these model organisms is the exception, rather than the rule, for eukaryotes. We describe endosymbiont-derived, bacterial-like division systems comprising FtsZ and Min proteins in diverse less-studied eukaryote protistan lineages, including jakobid and heterolobosean excavates, a malawimonad, stramenopiles, amoebozoans, a breviate, and an apusomonad. For two of these taxa, the amoebozoan Dictyostelium purpureum and the jakobid Andalucia incarcerata, we confirm a mitochondrial localization of these proteins by their heterologous expression in Saccharomyces cerevisiae. The discovery of a proteobacterial-like division system in mitochondria of diverse eukaryotic lineages suggests that it was the ancestral feature of all eukaryotic mitochondria and has been supplanted by a host-derived system multiple times in distinct eukaryote lineages.

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Euglena

Buetow¹

2011

Encyclopedia of Life Sciences

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Euglena is a genus of single‐celled, free‐living microorganisms that show both plant‐ and animal‐like characteristics. Members of the genus are found widely in nature and mainly in fresh waters. Most are aerobic and use photosynthesis or many organic compounds as interchangeable sources of carbon and energy. The most studied species is the easily grown E. gracilis which, in spite of its relatively rigid surface, can be subfractionated to yield nuclei, mitochondria, chloroplasts, flagella and pellicles. Subfractions show some unusual characteristics: The nuclear envelope remains intact throughout mitosis and chromosomes are permanently condensed at all phases of the cell cycle, the mitochondrial respiratory chain has two terminal oxidases, and chloroplasts have three membranes reflecting their endosymbiotic evolutionary history. Various Euglena and some of their constituent molecules are useful for environmental biomediation and potentially useful biomedically. Key Concepts: Euglena is a genus of single‐celled, free living microorganisms that show both plant‐ and animal‐like characteristics. More than 250 Euglena species have been described, though the actual number is not known. The majority of Euglena species are green due to the presence of chloroplasts containing chlorophylls a and b . Members of the genus Euglena are found widely in nature, inhabiting freshwater pools, ponds and lakes. Euglena are able to use photosynthesis and heterotrophic oxidative assimilation as interchangeable and apparently equivalent sources of carbon and energy. How to classify Euglena has been a long‐standing problem; the genus has been claimed as photosynthetic protozoa by zoologists and as algae by botanists. Studies on the genus Euglena , and especially E. gracilis , have been significant for understanding the biochemistry and molecular biology of nuclei and subcellular organisms.

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The Mitochondrion

Cited by 20 publications

References 269 publications

Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

Biochemistry and Evolution of Anaerobic Energy Metabolism in Eukaryotes

An ancestral bacterial division system is widespread in eukaryotic mitochondria

Euglena

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