Ultrastructure of some developmental stages of Helicosporidium sp. in the navel orangeworm, Paramyelois transitella

Lindegren, James E.; Hoffmann, Darlene F.

doi:10.1016/0022-2011(76)90034-3

Cited by 18 publications

(19 citation statements)

References 7 publications

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“…This result suggests that the early attempt of Kudo (1931) to classify this organism within the Protozoa may have been wrong, but it is consistent with studies by Weiser (1970) and Kellen & Lindegren (1974), both of which proposed the removal of the Helicosporidia from the Protozoa. However, in the most recent study of which we are aware, Lindegren & Hoffman (1976) refused this suggestion and reaffirmed that the Helicosporidia have affinities with the Protozoa, based on the presence of well-defined Golgi bodies and mitotic division of the nucleus.…”

Section: Discussionmentioning

confidence: 96%

“…They agreed that this organism is not a protozoan but remained uncertain about its taxonomic position. Later, Lindegren & Hoffman (1976) proposed that the developmental stages of this organism placed it closer to the Protozoa than to the Fungi. Because of this uncertain taxonomic status, the Helicosporidia have not appeared in classification systems of either the Protozoa or the Fungi (Cavalier-Smith, 1998 ;Tehler et al, 2000).…”

Section: Abbreviationsmentioning

confidence: 99%

“…Members of this group are characterized by the formation of a cyst stage that contains a core of three ovoid cells and a single filamentous cell ( Fig. 1) (Kellen & Lindegren, 1974 ;Lindegren & Hoffman, 1976). The group is very poorly known and its taxonomic position has remained incertae sedis.…”

Section: Introductionmentioning

confidence: 99%

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Phylogenetic analysis identifies the invertebrate pathogen Helicosporidium sp. as a green alga (Chlorophyta).

Tartar

Boucias²,

Adams³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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Historically, the invertebrate pathogens of the genus Helicosporidium were considered to be either protozoa or fungi, but the taxonomic position of this group has not been considered since 1931. Recently, a Helicosporidium sp., isolated from the blackfly Simulium jonesi Stone & Snoddy (Diptera : Simuliidae), has been amplified in the heterologous host Helicoverpa zea. Genomic DNA has been extracted from gradient-purified cysts. The 18S, 28S and 5.8S regions of the Helicosporidium rDNA, as well as partial sequences of the actin and β-tubulin genes, were amplified by PCR and sequenced.Comparative analysis of these nucleotide sequences was performed using neighbour-joining and maximum-parsimony methods. All inferred phylogenetic trees placed Helicosporidium sp. among the green algae (Chlorophyta), and this association was supported by bootstrap and parsimony jackknife values. Phylogenetic analysis focused on the green algae depicted Helicosporidium sp. as a close relative of Prototheca wickerhamii and Prototheca zopfii (Chlorophyta, Trebouxiophyceae), two achlorophylous, pathogenic green algae. On the basis of this phylogenetic analysis, Helicosporidium sp. is clearly neither a protist nor a fungus, but appears to be the first described algal invertebrate pathogen. These conclusions lead us to propose the transfer of the genus Helicosporidium to Chlorophyta, Trebouxiophyceae.

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Section: Discussionmentioning

confidence: 96%

Section: Abbreviationsmentioning

confidence: 99%

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Phylogenetic analysis identifies the invertebrate pathogen Helicosporidium sp. as a green alga (Chlorophyta).

Tartar

Boucias²,

Adams³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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“…Based on morphological comparisons, Lindegren & Hoffman (1976) introduced the hypothesis that there may be more than one species of Helicosporidium. However, to date, there is only one named species (Helicosporidium parasiticum Keilin 1921), and few comparative analyses have occurred.…”

Section: Discussionmentioning

confidence: 99%

Comparison of plastid 16S rRNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta)

Tartar

Boucias

Becnel

et al. 2003

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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The Helicosporidia are invertebrate pathogens that have recently been identified as non-photosynthetic green algae (Chlorophyta). In order to confirm the algal nature of the genus Helicosporidium, the presence of a retained chloroplast genome in Helicosporidia cells was investigated. Fragments homologous to plastid 16S rRNA (rrn16) genes were amplified successfully from cellular DNA extracted from two different Helicosporidium isolates. The fragment sequences are 1269 and 1266 bp long, are very AT-rich (60?7 %) and are similar to homologous genes sequenced from non-photosynthetic green algae. Maximum-parsimony, maximum-likelihood and neighbour-joining methods were used to infer phylogenetic trees from an rrn16 sequence alignment. All trees depicted the Helicosporidia as sister taxa to the non-photosynthetic, pathogenic alga Prototheca zopfii. Moreover, the trees identified Helicosporidium spp. as members of a clade that included the heterotrophic species Prototheca spp. and the mesotrophic species Chlorella protothecoides. The clade is always strongly supported by bootstrap values, suggesting that all these organisms share a most recent common ancestor. Phylogenetic analyses inferred from plastid 16S rRNA genes confirmed that the Helicosporidia are non-photosynthetic green algae, close relatives of the genus Prototheca (Chlorophyta, Trebouxiophyceae). Such phylogenetic affinities suggest that Helicosporidium spp. are likely to possess Prototheca-like organelles and organelle genomes.

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“…Here, vegetative cells develop, undergo several cycles of replication, and eventually form mature cysts (Boucias et al, 2001). Of the few histological studies that have investigated diVerent stages of helicosporidial infection in invertebrate hosts (Boucias et al, 2001;Keilin, 1921;Kellen and Lindegren, 1974;Lindegren and HoVmann, 1976;Pekkarinen, 1993;Purrini, 1984;Weiser, 1970), only two have speciWcally described the early events of hemolymph colonization by the pathogen.…”

Section: Introductionmentioning

confidence: 99%

Pathogenesis of Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in susceptible noctuid larvae

Bläske-Lietze¹,

Boucias²

2005

Journal of Invertebrate Pathology

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Ultrastructure of some developmental stages of Helicosporidium sp. in the navel orangeworm, Paramyelois transitella

Cited by 18 publications

References 7 publications

Phylogenetic analysis identifies the invertebrate pathogen Helicosporidium sp. as a green alga (Chlorophyta).

Phylogenetic analysis identifies the invertebrate pathogen Helicosporidium sp. as a green alga (Chlorophyta).

Comparison of plastid 16S rRNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta)

Pathogenesis of Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) in susceptible noctuid larvae

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