Recent data on the occurrence of species of the Paramecium aurelia complex in Europe

Among 15 species of the Paramecium aurelia complex known world-wide, 10 have been found in Europe, namely: P. primaurelia, P. biaurelia, P. triaurelia, P. tetraurelia, P. pentaurelia, P. sexaurelia, P. septaurelia, P. novaurelia, P. dodecaurelia, and P. tredecaurelia. Recent data on the frequency of occurrence of the species in Europe are given in the paper.     

Relationships of species of the Paramecium aurelia complex (Protozoa, Ph. Ciliophora, Cl. Oligohymenophorea) based on sequences of the histone H4 gene fragment

A fragment ofhistone H4 gene (160 bp long) was sequenced in the standard strains of P. primaurelia (DQ067620), P. biaurelia (DQ067621), P. tetraurelia (DQ067622), P. pentaurelia (DQ067623), P. septaurelia (DQ067624), P. octaurelia (DQ067625), P. decaurelia (DQ067626), P. undecaurelia (DQ067627), P. dodecaurelia (DQ067628), P. tredecaurelia (DQ067629), and P. quadecaurelia (DQ067630). The tree constructed according to the Kimura model presents two main species clusters, one comprising P. undecaurelia, P. octaurelia, P. septaurelia, and the second cluster with P. pentaurelia, P. tredecaurelia, P. quadecaurelia, P. tetraurelia, P. decaurelia, P. primaurelia, P. biaurelia. P. dodecaurelia was recovered as a separate branch. The tree constructed on the basis of the maximum likelihood method also presents two species clusters, one with P. undecaurelia, P. octaurelia, P. septaurelia, and the second with P. primaurelia, P. decaurelia, P. pentaurelia, P. tredecaurelia, P. quadecaurelia, P. tetraurelia. P. biaurelia forms a basal clade to the latter cluster, and P. dodecaurelia was recovered as a clearly distinct branch from the clusters.     

Molecular polymorphism of strains within Paramecium septaurelia (Ciliophora, Oligohymenophorea)

RAPD-PCR fingerprinting and ARDRA riboprinting revealed polymorphism within P. septaurelia strains from Russia (4 strains from Lower Volga Basin), and one strain from USA, Florida. However, the first method showed the existence of four RAPD genotypes while the second revealed only two groups of strains with different band patterns. All studied strains had a high percentage of surviving hybrid clones in the inter-strain crosses, with little differentiation of strains within species. Intra-species differentiation of strains in RAPD band patterns may be connected with the degree of inbreeding for the studied species. Species of the P. aurelia complex can be arranged according to the degree of inbreeding characteristic for each, which is correlated with the degree of DNA polymorphism revealed by the RAPD method from extreme inbreeders (e.g. P. sexaurelia), moderate inbreeders (e.g. P. triaurelia) to weak inbreeders (e.g. P. pentaurelia). P. septaurelia of the P. aurelia complex should be included in the group of extreme inbreeder.     

Occurrence of Paramecium species in Western Siberia, Russia

Paramecium strains collected in Central Russia, Western Siberia (the West Siberian Lowland and the Altai Mountains in the south) were studied. The presence of P. caudatum, P. bursaria, P. multimicronucleatum, P. polycaryum, and four species of the P. aurelia complex, i.e. P. primaurelia (in Omsk), P. biaurelia (in Krasnoyarsk and the Altai Mountains), P. triaurelia (in Krasnoyarsk), and P. pentaurelia (in Novosibirsk, Altai Foreland, and Altai Mountains) was revealed. P. triaurelia and P. pentaurelia were found for the first time in Asia.     

Polymorphism within Paramecium sexaurelia (Ciliophora, Oligohymenophorea) and description of a new stand of the species in China

The presence of Paramecium sexaurelia from the Paramecium aurelia complex was recorded for the first time in China (Beijing). RAPD fingerprints (band patterns) of P. sexaurelia strains, the new strain from China and others from Asia, as well as from Europe and Puerto Rico, showed polymorphism within the species as several groups of genotypes characterized by different band patterns.     

Interspecies Relationships in the Paramecium aurelia Complex: Acid Phosphatase Variation1

ABSTRACT. Up to five zones of acid phosphatase activity appear in gels after electrophoresis of detergent-treated extracts from 13 of the 14 species of the Paramecium aurelia complex. The overall pattern is somewhat similar for all species: differences in intensity and mobility of individual zones permit the grouping of these sibling species into eight groups. All 14 species can be identified using the procedure of enzyme electrophoresis, although two of them are more similar than is usually the case. Problems of misclassification are discussed in terms of the nature and frequency of variants. With the judicious choice of enzymes used to screen new stocks, these problems can be circumvented. Species relationships are updated using 11 enzymes. A dendrogram constructed from the matrix of genetic distances shows four clusters of species: (i) P. biaurelia, P. triaurelia; (ii) P. primaurelia, P. pentaurelia, P. sexaurelia, P. novaurelia; (iii) P. septaurelia, P. undecaurelia, P. tredecaurelia, P. quadecaurelia; and (iv) P. tetraurelia, P. octaurelia, P. decaurelia, P. dodecaurelia. Distances between the species are large, on the order of the differences between Drosophila species. The species are characterized by an extraordinary lack of geographical differentiation and great morphological similarity, which contrasts strongly with the molecular differentiation.     

A two-locus molecular characterization of Paramecium calkinsi

Paramecium calkinsi (Ciliophora, Protozoa) is a euryhaline species which was first identified in freshwater habitats, but subsequently several strains were also collected from brackish water. It is characterized by clockwise spiral swimming movement and the general morphology of the "bursaria type." The present paper is the first molecular characterization of P. calkinsi strains recently collected in distant regions in Russia using ITS1-5.8S- ITS2-5'LSU rDNA (1100bp) and COI (620bp) mtDNA sequenced gene fragments. For comparison, our molecular analysis includes P. bursaria, exhibiting a similar "bursaria morphotype" as well as species representing the "aurelia type," i.e., P. caudatum, P. multimicronucleatum, P. jenningsi, and P. schewiakoffi, and some species of the P. aurelia species complex (P. primaurelia, P. tetraurelia, P. sexaurelia, and P. tredecaurelia). We also use data from GenBank concerning other species in the genus Paramecium and Tetrahymena (which used as an outgroup). The division of the genus Paramecium into four subgenera (proposed by Fokin et al. 2004) is clearly presented by the trees. There is a clear separation between P. calkinsi strains collected from different regions (races). Consequently, given the molecular distances between them, it seems that these races may represent different syngens within the species.     

Species of the Paramecium aurelia complex (Protozoa, Ciliophora) in the Middle Sudetes of Poland

Four species of the Paramecium aurelia complex were found in the studied territory (Klodzko Basin) of the Middle Sudetes in Poland, i.e. Paramecium primaurelia, P. biaurelia, P. tetraurelia and P. novaurelia . Of these, P. biaurelia and P. novaurelia appeared with greater frequency than P. primaurelia . Both species dominated over P. primaurelia in the number of determined habitats, as well as in the number of examined clones. Paramecium tetraurelia was rare in the area, being found in only one habitat.     

Species of the Paramecium aurelia complex in Russia (western region of European Russia) with molecular characteristics of Paramecium novaurelia

The presence of P. primaurelia, P. biaurelia, P. triaurelia, and P. novaurelia of the P. aurelia complex was revealed in the studied region of Russia. RAPD-PCR fingerprints (band patterns) of newly identified P. novaurelia strains from Russia were compared to those characteristic for the other chosen European strains of the species. The strains revealed intraspecific polymorphism as several groups of genotypes confirming the existence of polymorphism within P. novaurelia.     

Species of the Paramecium aurelia complex in Italy

New stands of Paramecium pentaurelia were recorded in Valmarana, Veneto region in Italy and one stand of P. primaurelia was found at the same locality.     

西藏温泉两种中国新记录纤毛虫第一双小核草履虫和明布雷斯四膜虫的形态学和系统发育学研究

研究利用活体观察、蛋白银和氨银染色技术对采自西藏温泉的寡膜纲咽膜类纤毛虫第一双小核草履虫(Paramecium primaurelia)和膜口类纤毛虫明布雷斯四膜虫(Tetrahymena mimbres)进行了形态学研究, 首次描述了这两种纤毛虫细胞核器的形态和位置、纤毛图式和口膜的排布模式; 并且测定了SSU rDNA和COXⅠ标记基因序列, 基于这两种基因的系统发育树均支持P. primaurelia聚在草履虫P. aurelia复合种中, T. mimbres聚在四膜虫T. borealis类群中。两种纤毛虫均为中国新记录种, 且首次在高原温泉中发现, 不仅为西藏地区温泉原生动物生物资源的发掘提供新的方法和思路, 也为原生动物环境适应性研究提供基础资料。     

Organization and closing of mitochondrial deoxyribonucleic acid from Paramecium tetraaurelia and Paramecium primaurelia.

Previously we showed that the mitochondrial deoxyribonucleic acid (DNA) from Paramecium aurelia consists of a linear genome and that replication of this genome is initiated at one terminus and proceeds unidirectionally to the other terminus. Analyses of mitochondria from four closely related species (1, 4, 5, and 7) indicated that the species 1, 5, and 7 DNAs are essentially completely homologous but that the species 4 mitochondrial DNA is only 40 to 50% homologous with that from species 1. The major regions of homology are those containing the genes for ribosomal ribonucleic acid (RNA). To understand the replication and organization of the linear mitochondrial genome better, we compared species 1 (Paramecium primaurelia) and 4 (Paramecium tetraaurelia) DNAs with regard to restriction fragment mapping and homology between initiation regions; we also identified the sites of the genes for ribosomal RNA. In general, the structures of the species 1 and 4 mitochondrial genomes were quite similar. Each ribosomal RNA gene was present in one copy per genome, with the large ribosomal RNA gene located near the terminal region of replication and the small ribosomal RNA gene located more centrally. These two genes were separated by about 10 kilobases in the species 1 genome and by about 12 kilobases in the species 4 genome. In contrast to our previous findings, by using nonstringent hybridization conditions we detected homology between the species 1 and 4 DNA fragments containing the initiation regions. We constructed recombinant DNA clones for many fragments, especially those containing the initiation region and the ribosomal RNA genes. We also constructed restriction enzyme maps for six enzymes for both P. primaurelia and P. tetraaurelia.     

Paramecium aurelia species complex in the catchment area of the River Raba mountain course (the Carpathians)

In the water bodies of the Beskid Wyspowy Mts three species of the Paramecium aurelia complex have been found, i.e. P. biaurelia, P. tetraurelia and P. novaurelia. P. tetraurelia, which in Europe is a very rare species, was for the first time recorded in this region of the Carpathians.     

New, world-wide data on the distribution of species of the Paramecium aurelia complex (Ciliophora, Protozoa)

This is the first report on the presence of P. biaurelia in Tasmania, an island that has probably never been investigated before for the occurrence of the P. aurelia species. P. tetraurelia was recorded in Brazil, another very poorly investigated country in terms of this species complex. New stands of P. biaurelia and P. tetraurelia were also recorded in Japan. We present data concerning the occurrence and distribution of the P. aurelia species on different continents as a background for the newly described stands of P. aurelia spp.     

Phylogenetic relationships of the genus Paramecium inferred from small subunit rRNA gene sequences

The genus Paramecium includes species that are well known and very common in freshwater environments. Species of Paramecium are morphologically divided into two distinct groups: the "bursaria" subgroup (foot-shaped) and the "aurelia" subgroup (cigar-shaped). Their placement within the class Oligohymenophorea has been supported by the analysis of the small subunit rRNA gene sequence of P. tetraurelia. To confirm the stability of this placement and to resolve relationships within the genus, small subunit rRNA gene sequences of P. bursaria, P. calkinsi, P. duboscqui, P. jenningsi, P. nephridiatum, P. primaurelia, and P. polycaryum were determined and aligned. Trees constructed using distance-matrix, maximum-likelihood, and maximum-parsimony methods all depicted the genus as a monophyletic group, clustering with the other oligohymenophorean taxa. Within the Paramecium clade, P. bursaria branches basal to the other species, although the remaining species of the morphologically defined "bursaria" subgroup do not group with P. bursaria, nor do they form a monophyletic subgroup. However, the species of the "aurelia" subgroup are closely related and strongly supported as a monophyletic group.     

Paramecium sexaurelia in Croatia

The presence of Paramecium sexaurelia (two strains) was recorded in the National Park "Krka" in Croatia. This is the first record of the species, rare in Europe, in Croatia.     

Comparison of the evolutionary distances among syngens and sibling species of Paramecium

The morphospecies of the genus Paramecium have several mating type groups, so-called syngens, composed of cells of complementary mating types. The Paramecium aurelia complex is composed of 15 sibling species assigned to the species from the syngen. To increase our understanding of the evolutionary relationships among syngen and sibling species of the genus Paramecium, we investigated the gene sequences of cytosol-type hsp70 from 7 syngens of Paramecium caudatum and 15 sibling species of P. aurelia. Molecular phylogenetic trees indicated that the P. aurelia complex could be divided into four lineages and separated into each sibling species. However, we did not find any obvious genetic distance among syngens of P. caudatum, and they could only be separated into two closely related groups. These results indicated that the concept of syngens in P. caudatum differs quite markedly from that of the P. aurelia complex. In addition, we also discuss the relationships among these species and other species, Paramecium jenningsi and Paramecium multimicronucleatum, which were once classified as varieties of P. aurelia.     

Electrokaryotypes of macronuclei of several Paramecium species

A comparative study of macronuclear DNA molecules from the following Paramecium species: the P. aurelia complex, P. caudatum, P. bursaria, P. putrinum and P. multimicronucleatum was performed using pulsed-field gel electrophoresis. The electrophoretic pattern was constant and unique for each species, and is referred to herein as its electrokaryotype. Large differences were observed between Paramecium species according to the range and major size of macronuclear DNA fragments, while different strains of the same species, even belonging to different syngens, were characterized by the same electrokaryotype. In this respect sibling species from the P. aurelia complex are as similar as syngens in other Paramecium species, but are unlike conventional species. The principles and value of electrokaryotype analysis for application to ciliates are discussed.     

Comparison of the Esterases and Acid Phosphatases in Paramecium multimicronucleatum,Syngens 1–5, P. jenningsi,P. caudatum,and the P. aurelia Complex1

ABSTRACT. Forty-eight stocks in Paramecium jenningsi, syngens 1–5 of P. multimicronucleatum, P. caudatum, P. primaurelia, P. biaurelia, and P. tetraurelia were grown axenically and tested for their esterases and acid phosphatases using starch gel electrophoresis. The five esterases and the acid phosphatases previously characterized in species of the P. aurelia complex were also found in P. jenningsi, and three to four of the esterases and the acid phosphatases were found in the P. multimicronucleatum species complex and in P. caudatum. Additional subtypes were observed for each of the enzyme phenotypes in these new (though here unnamed) species of Paramecium. Two of the new acid phosphatase subtypes, which depart radically in mobility and in pattern, were found in syngen 3 of P. multimicronucleatum and in P. caudatum. Except for syngens 1 and 5 in P. multimicronucleatum, the degree of similarity between syngens 1, 5 and 2, 3, and 4 appears to be very low—perhaps even lower than that seen for species in the aurelia complex. More realistically, the syngens of P. multimicronucleatum should be considered as separate species although they are not here given separate taxonomic names. Limited sharing of subtypes occurred between species in different species complexes. This observation suggests that the molecular distances between species complexes may be even greater than between species within a complex.     

Relationships of new sibling species of Paramecium jenningsi based on sequences of the histone H4 gene fragment

Paramecium jenningsi Diller & Earl, 1958 belongs to the "aurelia" subgroup of the genus, together with Paramecium caudatum, Paramecium multimicronucleatum, Paramecium schewiakoffi and species of the Paramecium aurelia complex. The original assumption that the morphospecies P. jenningsi was a single genetic species was questioned because a comparison of genome analyses suggested the possibility that this morphospecies contained two sibling species. To refine understanding of relationships between the strains of P. jenningsi, a molecular phylogenetic analysis was conducted using H4 gene sequences. Some polymorphic sites were found among the compared sequences, and specific patterns of single nucleotide polymorphism (SNP) markers characterize two groups of strains of P. jenningsi. Phylogenetic trees constructed by different methods identified two clearly different groups (from Japan and mainland Asia) whatever the method used. The sequences of the H4 gene analyzed in the present study are closely related, and provide a good subject for phylogenetic analysis. The presence of two isolated groups of strains in the P. jenningsi group can reveal the evolutionary relationship between them; it confirms the presence of two sibling species among the known strains of P. jenningsi, and the close relationships between them and species of the P. aurelia complex.