Molecular data implicate bryozoans as hosts for PKX (Phylum Myxozoa) and identify a clade of bryozoan parasites within the Myxozoa

Parasitology ◽  
1999 ◽  
Vol 119 (6) ◽  
pp. 555-561 ◽  
Author(s):  
C. L. ANDERSON ◽  
E. U. CANNING ◽  
B. OKAMURA

Proliferative kidney disease (PKD), a condition associated with high mortality in salmonid fish, represents an abnormal immune response to the presence of an enigmatic myxozoan, which has been designated simply as PKX organism because its generic and specific status are obscure. Phylogenetic analyses of partial sequences of the 18S rDNA of PKX and of myxozoan parasites infecting the bryozoans Cristatella mucedo, Pectinatella magnifica and Plumatella rugosa, including the previously named Tetracapsula bryozoides from C. mucedo, showed that these taxa represent a distinct clade that diverged early in the evolution of the Myxozoa before the radiation of the other known myxozoan genera. A common feature of the myxozoans in this clade may be the electron-dense sporoplasmosomes with a lucent bar-like structure, which occur in T. bryozoides and PKX but not in the myxozoans belonging to the established orders Bivalvulida and Multivalvulida. Variation of 0·5–1·1% was found among the PKX 18S rDNA sequences obtained from fish from North America and Europe. The 18S rDNA sequence for T. bryozoides showed that it is a distinct taxon, not closely related to PKX but some sequences from myxozoans infecting 2 of the bryozoan species were so similar to those of PKX as to be indistinguishable. Other sequences from the new myxozoans in bryozoans at first appeared distinct from PKX in a maximum likelihood tree but, when analysed further, were also found to be phylogenetically indistinguishable from PKX. We propose that at least some variants of these new myxozoans from bryozoans are able to infect and multiply in salmonid fish, in which they stimulate the immune reaction and cause PKD but are unable to form mature spores to complete their development.

2019 ◽  
Vol 152 (3) ◽  
pp. 499-506 ◽  
Author(s):  
Oleg N. Shchepin ◽  
Martin Schnittler ◽  
Nikki H.A. Dagamac ◽  
Dmitry V. Leontyev ◽  
Yuri K. Novozhilov

Background and aims – Recent studies showed the position of two slime mould species with microscopic sporocarps, Echinosteliopsis oligospora and Echinostelium bisporum, within the class Myxomycetes. These minute species are seldom seen in studies based on detection of sporocarps and can easily be confused with protosteloid amoebozoans.Methods – We searched all published ePCR data sets that targeted myxomycete 18S rDNA for the presence of environmental sequences similar to E. oligospora and Echinosteliales in traditional circumscription, and performed phylogenetic analyses that included short environmental sequences and full-length 18S rDNA sequences representing all the major groups of myxomycetes.Key results – We report 19 unique sequences which are closely related to E. bisporum or E. oligospora based on sequence similarity (73.1–95.2% similarity) and which form well-supported monophyletic clades with these species in phylogenetic analyses. They may represent new species that are not yet described. Our phylogeny based on full-length 18S rDNA sequences further confirms the position of E. bisporum and E. oligospora within myxomycetes and the paraphyly of the order Echinosteliales in its traditional circumscription.Conclusions – Our results show that ePCR-based studies can reveal myxomycete taxa that often escape detection by traditional approaches, including potentially new species, and thus provide valuable new data on diversity and ecology of myxomycetes. As such, strategies for studying myxomycetes biodiversity should be revised, focusing also on molecular detection techniques in addition to the sporocarp-based ones.


Parasitology ◽  
2013 ◽  
Vol 141 (4) ◽  
pp. 522-530 ◽  
Author(s):  
NELA DVOŘÁKOVÁ ◽  
JANA KVIČEROVÁ ◽  
IVO PAPOUŠEK ◽  
HOSSEIN JAVANBAKHT ◽  
GHOULEM TIAR ◽  
...  

SUMMARYThe majority ofHaemogregarinaspecies have been based on the morphology of their erythrocytic stages and supposed strict host specificity. The quantity of species with a limited number of overlapping diagnostic traits has led to a considerable mess in haemogregarine taxonomy and significant synonymy. We analysed host specificity, intra- and interspecific variability, evolutionary relationships, and the distribution of the type species of the genusHaemogregarina–H. stepanowi.The morphology of blood stages and 18S rDNA sequences of this haemogregarine from four western Palaearctic hard-shelled freshwater turtles (Emys orbicularis, Mauremys caspica, Mauremys leprosaandMauremys rivulata) were compared withHaemogregarina balli. Additional sequences of 18S rDNA ofHaemogregarina-like isolates collected from three species of African hinged terrapins (genusPelusios) were used to enlarge the dataset for phylogenetic analyses. Thirteen sequences (1085 bp) ofHaemogregarinarepresenting all four western Palaearctic turtle species were identical, corresponding toH. stepanowi, which is closely related to the Nearctic speciesH. balli. In our analyses,Haemogregarinaspp. constituted a monophyletic clade sister to the genusHepatozoon. Haemogregarina stepanowipossesses a wide distribution range from the Maghreb, through Europe, Turkey and the Middle East to Iran. We consider that the genusHaemogregarinahas a low host specificity crossing the family level of its vertebrate hosts and that its distribution is likely to be linked to the vector and definitive host – the leech.


Nematology ◽  
2005 ◽  
Vol 7 (3) ◽  
pp. 363-373 ◽  
Author(s):  
S. Patricia Stock ◽  
Ana Caicedo ◽  
Paul Calatayud

AbstractRhabditis (Oscheius) colombiana n. sp. is described as a necromenic associate of the burrower bug Cyrtomenus bergi (Hemiptera: Cydnidae) collected in the Cauca Valley, Colombia. The new species resembles others of the insectivora-group, viz, Rhabditis (O.) insectivora Körner, 1954 and Rhabditis (O.) lucianii Maupas, 1919, in a number of morphological and life history traits, but can be separated by a combination of morphological and morphometric characters. The most distinctive morphological features that separate R. (O.) colombiana n. sp. from these two Rhabditis species are the total size of both males and females, which are much shorter and slimmer in the new species; the size of the male spicules and the values of ratios b and c. Additionally, molecular data (18S rDNA sequences) and phylogenetic analyses demonstrated the distinctiveness of this species when compared to a number of other Rhabditis (Oscheius) species.


2020 ◽  
Vol 70 (6) ◽  
pp. 3939-3952
Author(s):  
Harpreet Kaur ◽  
Shashi ◽  
Alan Warren ◽  
Ram Krishan Negi ◽  
Komal Kamra

The spirotrichean ciliate Stylonychia notophora has previously been recorded in India although the descriptions are lacking in detail. It has been suggested several times that the Indian population, S. notophora sensu Sapra and Dass, 1970 collected along the Delhi stretch of the River Yamuna, is identical to Tetmemena pustulata, but this has never been confirmed due to insufficient data for the former. The present study includes detailed descriptions (classical and molecular) of populations of Tetmemena isolated from six locations along the River Yamuna, India. These include four from the Delhi stretch including that from which Sapra and Dass, 1970 isolated their population of S. notophora. Due to the lack of a sufficiently detailed description, the taxonomic status of S. notophora sensu Sapra and Dass, 1970 was not clear. Comparisons among the populations isolated in the present study with previous descriptions of T. pustulata and S. notophora sensu Sapra and Dass, 1970 show only minor differences in morphometry, morphogenesis and in 18S rDNA sequences. The 18S rDNA sequences of all six populations had 99% similarity to both T. pustulata and S. notophora. These findings support the contention that S. notophora sensu Sapra and Dass, 1970 was misidentified and is a population of T. pustulata. This study supports the need for adopting an integrative approach based on morphological, morphogenetic and molecular data in order to understand species delimitation in ciliated protists.


2016 ◽  
Vol 2 ◽  
Author(s):  
MOSUN E. OGEDENGBE ◽  
JOSEPH D. OGEDENGBE ◽  
JULIA C. WHALE ◽  
KRISTIN ELLIOT ◽  
MARCO A. JUÁREZ-ESTRADA ◽  
...  

SUMMARYPartial mitochondrial cytochromecoxidase subunit I (mt COI) sequences were generated from:Toxoplasma gondii(strains CTG, GTI, MAS, ME49, PTG, TgCatBr5, TgCat, Br64, TgCgCal, TgToucan);Neospora caninum(Strain NC1);Hammondia hammondi(Strain H.H–20);H. heydorni; H. cf.triffittae; Cystoisospora felis; C. suis; C. canis; C. rivolta; C. cf.ohioensis; Caryospora bigenetica; Sarcocystis rileyi; andS. neurona. Nuclear 18S rDNA sequences were generated forH. heydorni, H. hammondi, C. suis, C. canis, C. felis, C. rivolta, C. cf.ohioensis, S. neurona, andS. rileyi. Aligned, concatenated 18S rDNA and COI sequences were Bayesian analysed using partitioned nucleotide substitution models [HKY + I + G for 18S; GTR + I + G codon (code = metmt) for COI]. Phylogenetic hypotheses supported a monophyletic Sarcocystidae and its subfamilie with two major clades within the Toxoplasmatinae: (1) a monophyletic clade ofCystoisosporaspp. withNephroisospora eptesici; and (2) a clade ofToxoplasma, NeosporaandHammondia. Within the latter,Hammondiawas shown to be paraphyletic;H. heydorniandH. triffittaewere monophyletic withN. caninum[canine definitive hosts (DHs)], whereasH. hammondiwas monophyletic withT. gondii(feline DHs). A new genus is erected to resolve the paraphyly of the genusHammondiaconfirmed using mt COI and combined 18S/COI sequence datasets.


2017 ◽  
Vol 39 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Nguyen Thi Huong Giang ◽  
Tran Duc Hoan ◽  
Nguyen Thi Thu Huyen ◽  
Nguyen Thi Kim Lan ◽  
Pham Ngoc Doanh

The genus Strongyloides is a group of parasitic nematodes of vertebrates comprised of over 50 species. A large numbers of nucleotide sequences of Strongyloides species have been deposited in GenBank. The vast majority of them are of Strongyloides from human beings, non-human primates, rats and cattle, but there are few molecular data of Strongyloides species isolated from pigs. The aim of this study is to identify Strongyloides species collected from pigs from Bac Giang Province, Vietnam, and analyze their molecular phylogenetic relationship within the genus Strongyloides based on 18S rDNA sequences. The morphological and molecular analyses revealed that the Strongyloides samples collected from pigs from Bac Giang Province, Vietnam, were in fact S. ransomi. The 18S rDNA sequences of S. ransomi from Vietnam were completely identical with that from Cambodia, but slightly different (0.3%) from that of Japan. In comparison to other Strongyloides species, S. ransomi was genetically close to S. venezuelensis. Citation: Nguyen Thi Giang, Tran Duc Hoan, Nguyen Thi Thu Huyen, Nguyen Thi Kim Lan, Phạm Ngọc Doanh, 2017. Morphological and molecular characterisation of Strongyloides ransomi (Nematoda: Strongyloididae) collected from domestic pigs in Bac Giang province, Vietnam. Tap chi Sinh hoc, 39(3): 270- 275. DOI: 10.15625/0866-7160/v39n3.10796.*Corresponding author: [email protected] 18 May 2017, accepted 20 August 2017 


Zootaxa ◽  
2013 ◽  
Vol 3599 (2) ◽  
pp. 161-177 ◽  
Author(s):  
REGINA WETZER ◽  
MARCOS PÉREZ-LOSADA ◽  
NIEL L. BRUCE

Based on 18S-rDNA sequences of 97 isopods including 18 Sphaeromatidea, we show Sphaeromatidae, Valvifera, Serolidae, and Ancinidae is a well supported clade. The within clade relationships of these taxa are not as definitively demonstrated because taxon sampling for some groups is still limited. In our analyses the Sphaeromatidae are shown to be unequivocally monophyletic. This is contrary to the morphology-based analysis by A. Brandt and G. Poore in 2003, which included only five Sphaeromatidae and found the family to be paraphyletic. The Ancinidae are also upheld, and the Valvifera is the sister taxon to Serolidae. Surprisingly Plakarthrium (Plakarthiidae) is nested within the Sphaeromatidae in most analyses. We point out short-comings in our sampling and suggest areas which would benefit from better sampling. We also review the long and convoluted nomenclatural history of the Sphaeromatidea, Sphaeromatoidea, and Sphaeromatidae.


Author(s):  
Rebecca J. Rundell ◽  
Brian S. Leander

The spaces between sand grains are home to a myriad of microscopic marine eukaryotes, including kalyptorhynch rhabdocoels equipped with an eversible proboscis that enables them to capture microscopic prey living in these environments. The structure of the kalyptorhynch proboscis separates the two major subclades within the group: the Schizorhynchia (bifurcated proboscis) and the Eukalyptorhynchia (unbranched proboscis). A survey of meiofaunal metazoans in the Pacific north-west led to the discovery of three new schizorhynch species (Undicola tofinoensisgen. nov., sp. nov.,Schizorhinos vancouverensisgen. nov., sp. nov. andLinguabana tulaigen. nov., sp. nov.) and two new eukalyptorhynch species (Thinodactylaina tlaoquiahtensisgen. nov., sp. nov. andRostracilla nuuchahnulthensisgen. nov., sp. nov.). This survey also recovered the putative cosmopolitan eukalyptorhynch (Polycystididae)Gyratrix hermaphroditusEhrenberg, 1831. We performed molecular phylogenetic analyses on 18S rDNA sequences from all five novel isolates and from all available kalyptorhynch species in GenBank. The molecular data supported the monophyly of the Eukalyptorhynchia and Schizorhynchia and helped demonstrate the boundaries between different species within the Kalyptorhynchia.


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