scholarly journals Phylogenetic Analysis of Rhinosporidium seeberi’s 18S Small-Subunit Ribosomal DNA Groups This Pathogen among Members of the Protoctistan Mesomycetozoa Clade

1999 ◽  
Vol 37 (9) ◽  
pp. 2750-2754 ◽  
Author(s):  
Roger A. Herr ◽  
Libero Ajello ◽  
John W. Taylor ◽  
Sarath N. Arseculeratne ◽  
Leonel Mendoza
Keyword(s):  
Phylogenetic Analysis ◽  
Ribosomal Dna ◽  
Phylogenetic Analyses ◽  
Small Subunit ◽  
Fish Parasites ◽  
Distance Methods ◽  
Spherical Structures ◽  
Molecular Affinity ◽  
Phylogenetic Affinities ◽  
Small Subunit Ribosomal Dna

For the past 100 years the phylogenetic affinities ofRhinosporidium seeberi have been controversial. Based on its morphological features, it has been classified as a protozoan or as a member of the kingdom Fungi. We have amplified and sequenced nearly a full-length 18S small-subunit (SSU) ribosomal DNA (rDNA) sequence fromR. seeberi. Using phylogenetic analysis, by parsimony and distance methods, of R. seeberi’s 18S SSU rDNA and that of other eukaryotes, we found that this enigmatic pathogen of humans and animals clusters with a novel group of fish parasites referred to as the DRIP clade (Dermocystidium, rossete agent,Ichthyophonus, and Psorospermium), near the animal-fungal divergence. Our phylogenetic analyses also indicate thatR. seeberi is the sister taxon of the twoDermocystidium species used in this study. This molecular affinity is remarkable since members of the genusDermocystidium form spherical structures in infected hosts, produce endospores, have not been cultured, and possess mitochondria with flat cristae. With the addition of R. seeberi to this clade, the acronym DRIP is no longer appropriate. We propose to name this monophyletic clade Mesomycetozoa to reflect the group’s phylogenetic association within the Eucarya.

Systematic status of Campydora Cobb, 1920 (Nematoda: Campydorina)

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 699-711 ◽  
Author(s):  
Peter Mullin ◽  
Timothy Harris ◽  
Thomas Powers
Keyword(s):  
Maximum Likelihood ◽  
Ribosomal Dna ◽  
Dna Sequences ◽  
Maximum Parsimony ◽  
Phylogenetic Analyses ◽  
Small Subunit ◽  
Systematic Position ◽  
Nominal Species ◽  
Competing Hypotheses ◽  
Small Subunit Ribosomal Dna

AbstractThe systematic position of Campydora Cobb, 1920, which possesses many unique morphological features, especially in pharyngeal structure and stomatal armature, has long been a matter of uncertainty with the 'position of the Campydorinae' (containing only Campydora) being questionable. A review of the morphology of C. demonstrans, the only nominal species of Campydora concluded that the species warranted placement as the sole member of a monotypic suborder, Campydorina, in the order Dorylaimida. Others placed Campydorina in the order Enoplida. We conducted phylogenetic analyses, using 18s small subunit ribosomal DNA sequences generated from a number of taxa in the subclasses Enoplia and Dorylaimia, to evaluate these competing hypotheses. Although precise taxonomic placement of the genus Campydora and the identity of its closest living relatives is in need of further investigation, our analyses, under maximum parsimony, distance, and maximum likelihood criteria, unambiguously indicate that Campydora shares a common, more recent, ancestry with genera such as Alaimus, Pontonema, Tripyla and Ironus (Enoplida), rather than with any members of Dorylaimida, Mononchida or Triplonchida.

scholarly journals Sequences of psychrophilic fungi amplified from glacier-preserved ascolichens

2000 ◽  
Vol 78 (11) ◽  
pp. 1450-1459 ◽  
Author(s):  
Paula T DePriest ◽  
Natalia V Ivanova ◽  
Dianne Fahselt ◽  
Vagn Alstrup ◽  
Andrea Gargas
Keyword(s):  
Phylogenetic Analysis ◽  
Ribosomal Dna ◽  
Dna Sequences ◽  
Large Subunit ◽  
Ice Core ◽  
Small Subunit ◽  
Rdna Sequences ◽  
Three Samples ◽  
Tyrolean Iceman ◽  
Small Subunit Ribosomal Dna

Ribosomal DNA sequences were amplified from subfossils of the ascolichen Umbilicaria cylindrica (L.) Delise ex Duby collected at the ablating edges of Greenland glaciers. Surprisingly, phylogenetic analysis indicated that the amplified rDNA sequences were not closely related to those of the lichen-forming fungus but rather represented two groups of psychrophilic basidiomycetes (orders Cystofilobasidiales and Sporidiales) and one group of ascomycetes (order Leotiales). Two of these groups, the Sporidiales and the Leotiales, include other fungi previously detected in DNA extracted from the grass clothing of the Tyrolean Iceman desiccated and frozen for over 3000 years and also in 2000- and 4000-year-old ice core samples from northern Greenland. Large subunit ribosomal DNA sequences representing the group Cystofilobasidiales were nearly identical to those of the basidioyeast saprobe Mrakia frigida. The adjacent internal transcribed spacer sequence was more than 98% similar to those from three samples of U. cylindrica from different sites that had been subjected to ice burial for various lengths of time, suggesting they also were Mrakia sequences. Although ancient contamination of multiple U. cylindrica specimens with fungi such as Mrakia cannot be ruled out, it is more probable that saprobic colonization of the subfossil tissues by psychrophilic fungi proceeded during recent ice melt.Key words: ancient DNA, small subunit ribosomal DNA, 18S ribosomal DNA, phylogenetic analysis, psychrophilic fungi, lichen-forming fungi.

Small subunit ribosomal DNA phylogeny of microsporidia that infect Daphnia (Crustacea: Cladocera)

Parasitology ◽  
2002 ◽  
Vol 124 (4) ◽  
pp. 381-389 ◽  
Author(s):  
D. REFARDT ◽  
E. U. CANNING ◽  
A. MATHIS ◽  
S. A. CHENEY ◽  
N. J. LAFRANCHI-TRISTEM ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Ribosomal Dna ◽  
Small Subunit ◽  
Close Relative ◽  
Human Pathogen ◽  
Intermediate Hosts ◽  
Dna Phylogeny ◽  
Virulence Group ◽  
Small Subunit Ribosomal Dna ◽  
Glugoides Intestinalis

Glugoides intestinalis, Microsporidium sp., Ordospora colligata, Gurleya vavrai, Larssonia obtusa and Flabelliforma magnivora are microsporidian parasites of planctonic freshwater crustaceans Daphnia spp. We performed a phylogenetic analysis of the small subunit ribosomal DNA which revealed their positions as polyphyletic. G. intestinalis, Microsporidium sp. and O. colligata, which are horizontally transmitted gut parasites with small spores and low virulence, group with different lineages. G. intestinalis is related to 2 microsporidia infecting lepidopterans and to Vittaforma corneae, which has been described as a human pathogen. It is thought that V. corneae may have an invertebrate as its natural host. Microsporidium sp. is a relative of the genera Enterocytozoon and Nucleospora, pathogens of man and fish respectively. O. colligata is the first species found to be closely related to the genus Encephalitozoon, which is comprised of 3 species that are parasites of homeothermic vertebrates. G. vavrai and L. obtusa are sister taxa that branch close to the Amblyosporidae, the only microsporidia with known intermediate hosts. This finding supports the presumption of secondary hosts for G. vavrai and L. obtusa, as it has not been possible to maintain these species in Daphnia in the laboratory. F. magnivora roots deep at the base of the phylum microsporidia with no close relative found so far.

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