Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Keeling, Patrick J.; Doolittle, W. Ford

doi:10.1073/pnas.94.4.1270

Cited by 108 publications

(60 citation statements)

References 38 publications

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“…The phylogenetic affinities of the TPI gene family have been reinvestigated using data not available in 1997. An analysis of three ␣-proteobacterial homologues of TPI together with 50 other homologues from eukaryotes and bacteria extend the findings of Keeling and Doolittle (97). The data confirm the observation that there is no specific relationship between the TPIs of ␣-proteobacteria and those of eukaryotes (Canbäck et al, unpublished).…”

Section: Vol 64 2000supporting

confidence: 78%

“…The absence of strong support for a specific ␣-proteobacterial descent of eukaryotic TPI led them to subject the data to further statistical analyses. Here, they could find topologies in which the eukaryotic cluster of TPI was closest to ␣-proteobacterial TPI, but "the difference between R. etli specifically and all the proteobacteria was often insignificant" (97). Nevertheless, they summarize their data by suggesting that "TPI genes present in eukaryotic genomes were derived from an alpha-proteobacterial genome (possibly that of the protoendosymbiont)" (97).…”

Section: Vol 64 2000mentioning

confidence: 99%

“…Here, they could find topologies in which the eukaryotic cluster of TPI was closest to ␣-proteobacterial TPI, but "the difference between R. etli specifically and all the proteobacteria was often insignificant" (97). Nevertheless, they summarize their data by suggesting that "TPI genes present in eukaryotic genomes were derived from an alpha-proteobacterial genome (possibly that of the protoendosymbiont)" (97). They also note that among these putative descendants of ␣-proteobacterial TPI is that of the amitochondrial Giardia spp.…”

Section: Vol 64 2000mentioning

confidence: 99%

“…Keeling and Doolittle (97), in a much-cited paper, analyzed the phylogenetic descent of triosephosphate isomerase (TPI). They presented two phylogenetic reconstructions, one an unweighted parsimony tree and the other a neighbor-joining dis- FIG.…”

Section: Archaeazoamentioning

confidence: 99%

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Origin and Evolution of the Mitochondrial Proteome

Kurland

Andersson

2000

Microbiol Mol Biol Rev

364

272

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SUMMARY The endosymbiotic theory for the origin of mitochondria requires substantial modification. The three identifiable ancestral sources to the proteome of mitochondria are proteins descended from the ancestral α-proteobacteria symbiont, proteins with no homology to bacterial orthologs, and diverse proteins with bacterial affinities not derived from α-proteobacteria. Random mutations in the form of deletions large and small seem to have eliminated nonessential genes from the endosymbiont-mitochondrial genome lineages. This process, together with the transfer of genes from the endosymbiont-mitochondrial genome to nuclei, has led to a marked reduction in the size of mitochondrial genomes. All proteins of bacterial descent that are encoded by nuclear genes were probably transferred by the same mechanism, involving the disintegration of mitochondria or bacteria by the intracellular membranous vacuoles of cells to release nucleic acid fragments that transform the nuclear genome. This ongoing process has intermittently introduced bacterial genes to nuclear genomes. The genomes of the last common ancestor of all organisms, in particular of mitochondria, encoded cytochrome oxidase homologues. There are no phylogenetic indications either in the mitochondrial proteome or in the nuclear genomes that the initial or subsequent function of the ancestor to the mitochondria was anaerobic. In contrast, there are indications that relatively advanced eukaryotes adapted to anaerobiosis by dismantling their mitochondria and refitting them as hydrogenosomes. Accordingly, a continuous history of aerobic respiration seems to have been the fate of most mitochondrial lineages. The initial phases of this history may have involved aerobic respiration by the symbiont functioning as a scavenger of toxic oxygen. The transition to mitochondria capable of active ATP export to the host cell seems to have required recruitment of eukaryotic ATP transport proteins from the nucleus. The identity of the ancestral host of the α-proteobacterial endosymbiont is unclear, but there is no indication that it was an autotroph. There are no indications of a specific α-proteobacterial origin to genes for glycolysis. In the absence of data to the contrary, it is assumed that the ancestral host cell was a heterotroph.

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Section: Vol 64 2000supporting

confidence: 78%

Section: Vol 64 2000mentioning

confidence: 99%

Section: Vol 64 2000mentioning

confidence: 99%

Section: Archaeazoamentioning

confidence: 99%

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Origin and Evolution of the Mitochondrial Proteome

Kurland

Andersson

2000

Microbiol Mol Biol Rev

364

272

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“…One of the mean features that strengthens the relationship between microsporidia and fungi is the presence of chitin and trehalose (2,4,15,22).…”

Section: Discussionmentioning

confidence: 99%

In Vitro Efficacy of Nikkomycin Z against the Human Isolate of the Microsporidian Species Encephalitozoon hellem

Bigliardi

Bernuzzi

Corona

et al. 2000

Antimicrob Agents Chemother

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Since 1985 microsporidia have been recognized as a cause of emerging infections in humans, mainly in immunocompromised human immunodeficiency virus-positive subjects. As chitin is a basic component of the microsporidian infective stage, the spore, we evaluated in vitro the susceptibility of a human-derived strain of Encephalitozoon hellem to nikkomycin Z, a peptide-nucleoside antibiotic known as a competitive inhibitor of chitin synthase enzymes. Transmission electron microscopy showed that this drug, at 25 g/ml, reduced the number of parasitic foci by about 35% ؎ standard deviation after 7 days of culture (P < 0.0001) and induced cell damage of both mature and immature spores and also other sporogonic and merogonic stages. In particular, an irregular outline of the cell shape and an abnormally condensed cytoplasm in meronts and sporonts were documented. Also, the polar tubule and the polaroplast membranes appeared disarrayed in the sporoblast stage. The spore wall showed an enlarged endospore and delaminated exospore. Mature spores had a complete cytoplasmic disorganization and a swollen and delaminated cell wall. No ultrastructural cell damage was observed in uninfected control cultures treated with the drug.Microsporidia are widespread, obligate intracellular parasites of most vertebrates and invertebrates. In addition to their causing infections in animals (19), there is great interest in studying these microorganisms because some genera and species have been recognized as a cause of opportunistic infections in immunocompromised humans, chiefly human immunodeficiency virus-positive subjects (9). Although albendazole, a benzimidazole derivative, has been found to be effective in vitro and in a series of patients infected by Encephalitozoon spp. to date there are no other drugs that are proved consistently efficacious against microsporidia infecting humans.The microsporidian spore is the stage of the parasite that contains chitin in the cell wall (2, 3, 4). Chitin provides high resistance to the environment and confers structural rigidity to the infective stage. Chitin is a carbohydrate polymer not present in mammalian cells, and chitin synthesis inhibition should be a target for microsporidian-specific therapy.Nikkomycin Z (NIK-Z) is a peptide-nucleoside antibiotic that was recovered as a potent competitive inhibitor of chitin synthase enzymes of fungi and insects and has structural similarity to UDP-N-acetylglucosamine (6, 7). In particular NIK-Z has been found to be effective in vitro and in vivo against some extracellular and intracellular fungal pathogens (5, 12, 13, 16). Moreover, this drug is well tolerated and easily degradable (11, 12) and therefore also might be considered as a potential candidate for therapeutic use against microsporidia. We present the results of a preliminary in vitro study on the sensitivity of NIK-Z on a human isolate of Encephalitozoon hellem. MATERIALS AND METHODSCulture system. The study was performed on a E. hellem isolate (PV-5-95) from a subject with asymptomatic microspo...

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A kingdom's progress: Archezoa and the origin of eukaryotes

Keeling

1998

Bioessays

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The taxon Archezoa was proposed to unite a group of very odd eukaryotes that lack many of the characteristics classically associated with nucleated cells, in particular the mitochondrion. The hypothesis was that these cells diverged from other eukaryotes before these characters ever evolved, and therefore they represent ancient and primitive eukaryotic lineages. The kingdom comprised four groups: Metamonada, Microsporidia, Parabasalia, and Archamoebae. Until recently, molecular work supported their primitive status, as they consistently branched deeply in eukaryotic phylogenetic trees. However, evidence has now emerged that many Archezoa contain genes derived from the mitochondrial symbiont, revealing that they actually evolved after the mitochondrial symbiosis. In addition, some Archezoa have now been shown to have evolved more recently than previously believed, especially the Microsporidia for which considerable evidence now indicates a relationship with fungi. In summary, the mitochondrial symbiosis now appears to predate all Archezoa and perhaps all presently known eukaryotes. BioEssays 20:87–95, 1998. © 1998 John Wiley & Sons, Inc.

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Evidence that eukaryotic triosephosphate isomerase is of alpha-proteobacterial origin

Cited by 108 publications

References 38 publications

Origin and Evolution of the Mitochondrial Proteome

Origin and Evolution of the Mitochondrial Proteome

In Vitro Efficacy of Nikkomycin Z against the Human Isolate of the Microsporidian Species Encephalitozoon hellem

A kingdom's progress: Archezoa and the origin of eukaryotes

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