A New Algal Class — The Eustigmatophyceae

Hibberd, David J.; Leedale, Gordon F.

doi:10.2307/1218254

Cited by 66 publications

(30 citation statements)

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“…The major classes in this group comprised the phaeophytes, chrysophytes, synurophytes, xanthophytes, eustigmatophytes, raphidophytes, bacillariophytes, dictyochophytes, pelagophytes and phaeothamniophytes (Hibberd & Leedale, 1970, 1971, 1972Ettl, 1978 ;Silva, 1980 ;Andersen, 1987 ;Heywood, 1990 ;Andersen et al, 1993Andersen et al, , 1998Andersen et al, , 1999Potter et al, 1997 ;Bailey et al, 1998). The heterokont algae are thus a diverse assemblage of many different smaller groups of algae.…”

Section: Introductionmentioning

confidence: 99%

“…The heterokont algae, also referred to as 'stramenochromes ' (Leipe et al, 1994) and 'Ochrista' (Cavalier-Smith et al, 1994b), consist A. Ben Ali and others of different subgroups that share morphological features such as the possession of tripartite tubular flagellar hairs, similar flagellar anchorage systems (based on four microtubular roots) and electrondense mitochondria with short tubular cristae (Patterson, 1989). The major classes in this group comprised the phaeophytes, chrysophytes, synurophytes, xanthophytes, eustigmatophytes, raphidophytes, bacillariophytes, dictyochophytes, pelagophytes and phaeothamniophytes (Hibberd & Leedale, 1970, 1971, 1972 Ettl, 1978 ;Silva, 1980 ;Andersen, 1987 ;Heywood, 1990 ;Andersen et al, 1993Andersen et al, , 1998Andersen et al, , 1999Potter et al, 1997 ;Bailey et al, 1998). The heterokont algae are thus a diverse assemblage of many different smaller groups of algae.…”

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Phylogenetic relationships among algae based on complete large-subunit rRNA sequences.

Ali¹,

Baere²,

Auwera³

et al. 2001

International Journal of Systematic and Evolutionary Microbiology

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The complete or nearly complete large-subunit rRNA (LSU rRNA) sequences were determined for representatives of several algal groups such as the chlorarachniophytes, cryptomonads, haptophytes, bacillariophytes, dictyochophytes and pelagophytes. Our aim was to study the phylogenetic position and relationships of the different groups of algae, and in particular to study the relationships among the different classes of heterokont algae. In LSU rRNA phylogenies, the chlorarachniophytes, cryptomonads and haptophytes seem to form independent evolutionary lineages, for which a specific relationship with any of the other eukaryotic taxa cannot be demonstrated. This is in accordance with phylogenies inferred on the basis of the smallsubunit rRNA (SSU rRNA). Regarding the heterokont algae, which form a wellsupported monophyletic lineage on the basis of LSU rRNA, resolution between the different classes could be improved by combining the SSU and LSU rRNA data. Based on a concatenated alignment of both molecules, the phaeophytes and the xanthophytes are sister taxa, as well as the pelagophytes and the dictyochophytes, and the chrysophytes and the eustigmatophytes. All these sister group relationships are highly supported by bootstrap analysis and by different methods of tree construction.Keywords : heterokont algae, cryptophytes, chlorarachniophytes, haptophytes, large-subunit rRNA (LSU rRNA) INTRODUCTIONGenerally, on the basis of pigmentation, three main eukaryotic algal groups have been discerned, namely the chlorophytes or green algae (characterized by the presence of chlorophyll a and b), the rhodophytes or red algae (chlorophyll a and phycobilins), and the chromophytes or yellow-brown algae (chlorophyll a and c, and absence of chlorophyll b). The latter group, which is polyphyletic, is further subdivided into four taxa, namely the cryptophytes, the haptophytes, the dinoflagellates and the heterokont algae, on the basis of pigmentation and plastid ultrastructure, flagellar apparatus and small-subunit rRNA (SSU rRNA). phylogenies (Whatley, 1989 ; Bhattacharya et al., 1992 ;Leipe et al., 1994 ; Cavalier-Smith et al., 1994a ;Medlin et al., 1995).The cryptophytes or cryptomonads (Gillot, 1990) are unicellular biflagellated organisms for which the evolutionary history is unclear and controversial. In previous studies, they have been phylogenetically positioned with chlorobionts (Eschbach et al., 1991), other chromophytes (Cavalier-Smith et al., 1994a), glaucocystophytes (Bhattacharya et al., 1995a ;Ragan & Gutell, 1995 ;Van de Peer et al., 1996a) and Acanthamoeba (McFadden, 1993). The haptophytes or prymnesiophytes (Green et al., 1990) are unicellular flagellate cells, characterized by a filiform organelle associated with the flagella, called the haptonema. Also for this group of organisms, the phylogenetic status is rather unclear (Daugbjerg & Andersen, 1997a ; and references therein). The heterokont algae, also referred to as 'stramenochromes ' (Leipe et al., 1994) and 'Ochrista' (Cavalier-Smith et al., 1994b), consist A....

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Phylogenetic relationships among algae based on complete large-subunit rRNA sequences.

Ali¹,

Baere²,

Auwera³

et al. 2001

International Journal of Systematic and Evolutionary Microbiology

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show abstract

“…Eustigmatophytes have been segregated from yellowgreen algae (xanthophytes) mainly on the basis of the ultrastructural characteristics of their chloroplasts and flagella (Hibberd and Leedale 1971). These organisms have chlorophyll a, but not chlorophyll b or c, and they do not possess any girdle lamella in their chloroplasts, but bear an eyespot at the anterior end of the motile cell (Hibberd 1989a).…”

Section: Introductionmentioning

confidence: 99%

Use of a deviant mitochondrial genetic code in yellow-green algae as a landmark for segregating members within the phylum

et al. 1997

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Several algae that were previously classified in the phylum Xanthophyta (yellow-green algae) were assigned in 1971 to a new phylum, Eustigmatophyta. It was anticipated that the number of algae reclassified to Eustigmatophyta would increase. However, due to the fact that the morphological characteristics that segregate eustigmatophytes from other closely related algae can be only obtained through laborious electron microscopic techniques, the number of members in this phylum have increased rather slowly. We attempted, therefore, to segregate two closely related groups of algae, eustigmatophytes and yellow-green algae, on the basis of a molecular phylogenetic tree as a means of providing an alternative method of distinguishing these phyla. We analyzed the mitochondrial cytochrome oxidase subunit I (COXI) gene sequences of eight algae classified as xanthophyceans and found that six manifested the expected deviant genetic code where AUA codes for methionine (AUA/Met), but not for isoleucine (AUA/Ile) as in the universal genetic code. The other two, Monodus sp. (CCMP 505) and Ophiocytium majus (CCAP 855/1), which were presumed to be yellow-green algae, and all the examined eustigmatophytes utilized AUA for Ile. In addition, the phylogenetic tree of COXI gene sequences showed that the six yellow-green algae bearing the AUA/Met deviant code composed a tight clade with a bootstrap value of 100%. The phylogenetic tree of the corresponding sequences from Monodus sp. and Ophiocytium majus and the eustigmatophytes also composed a tight cluster, but with a bootstrap value of 92%. These results strongly suggest that two previously classified members of yellow-green algae belong to the phylum Eustigmatophyta. Therefore, examination of the mitochondrial genetic code in algae appears to be a potentially very useful genetic marker for classifying these organisms, especially when it is considered with the results obtained through a molecular phylogenetic tree.

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“…The Eustigmatophyta was first recognized as a separate taxonomic group in 1971 (Hibberd & Leedale, 1971), and is a part of the Heterokonta, which is within the chromalveolates and contains many algal species. Based on molecular evidence, Takishita et al (2009) showed that the GAPDH sequence in another eustigmatophyte, Nannochloropsis oculata, is closely related to diatoms and chrysophytes.…”

Section: Phylogenetic Diversity In Gapdh Regulationmentioning

confidence: 99%

Regulation of glyceraldehyde-3-phosphate dehydrogenase in the eustigmatophytePseudocharaciopsis ovalisis intermediate between a chlorophyte and a diatom

Avilán

Maberly

Mekhalfi

et al. 2012

European Journal of Phycology

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The regulation of NADPH-dependent GAPDH was analysed in the chromalveolate (eustigmatophyte) Pseudocharaciopsis ovalis and compared with the well-studied chlorophyte Chlamydomonas reinhardtii and with another chromalveolate (diatom), Asterionella formosa. Optimal pH for GAPDH activity in P. ovalis and C. reinhardtii ranged between 8 and 9, but in A. formosa ranged between 6.2 and 8.1. Assuming dark pH values of about 7 in the plastids of all three species, GAPDH would be down-regulated in the dark in C. reinhardtii and P. ovalis, but fully active in A. formosa. The time required for halfmaximal GAPDH activity on transfer to reducing conditions, was significantly different in each species: 1.4, 4.0 and 5.9 min in A. formosa, P. ovalis and C. reinhardtii respectively. Under oxidized conditions in P. ovalis and A. formosa, NADPH caused a large inhibition in GAPDH activity even at very low concentrations (10 to 20 mM) unlike in C. reinhardtii. This inhibition was relieved by addition of a reducing agent suggesting that NADPH can control GAPDH activity under dark-light transitions. A small increase of GAPDH activity with NADP at concentrations higher than 0.5 mM was observed with P. ovalis and C. reinhardtii, while a greater than 1.5-fold stimulation was observed in A. formosa. Regulation of GAPDH in P. ovalis was intermediate between the diatom and the chlorophyte and the possible evolutionary reasons for this are discussed.

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A New Algal Class — The Eustigmatophyceae

Cited by 66 publications

References 6 publications

Phylogenetic relationships among algae based on complete large-subunit rRNA sequences.

Phylogenetic relationships among algae based on complete large-subunit rRNA sequences.

Use of a deviant mitochondrial genetic code in yellow-green algae as a landmark for segregating members within the phylum

Regulation of glyceraldehyde-3-phosphate dehydrogenase in the eustigmatophytePseudocharaciopsis ovalisis intermediate between a chlorophyte and a diatom

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