Morphological description and molecular identification of n. sp. (Myxozoa: Myxobolidae) from the gill of in southwest China.

Background: Myxosporean diversity is a hot topic since they are difficult to accurately identify and classify. Many parasites have been named as because of their similar morphological features with the species originally reported. However, the distinctions in fine morphological features, host specificity, and molecular data have given rise to the attention of researchers.

A New Molecular Approach Based on the Secondary Structure of Ribosomal RNA for Phylogenetic Analysis of Mobilid Ciliates.

We analyzed the secondary structure of the small subunit (SSU) rRNA genes of Mobilida (Ciliophora, Peritrichia) and found that the secondary structures of some regions within the SSU-rRNA gene are distinct between the families Trichodinidae and Urceolariidae. Therefore, some of these important regions including H10, H11, H17, H47, H29, H30, H37, E10-1, H45-H46, and V4 (E23-4, E23-7) could be used as the barcodes for classification of these two families. In contrast, V4 (E23-1, E23-2) belongs to a hypervariable region and is not a good barcode at the genus level because of its great inter-specific variation.

New Comparative Analysis Based on the Secondary Structure of SSU-rRNA Gene Reveals the Evolutionary Trend and the Family-Genus Characters of Mobilida (Ciliophora, Peritrichia).

In order to reveal the structural evolutionary trend of Mobilida ciliates, twenty-six SSU-rRNA sequences of mobilid species, including seven ones newly sequenced in the present work, were used for comparative phylogenic analysis based on the RNA secondary structure. The research results indicate that all the secondary structures except domains Helix 10, Helix 12, and Helix 37 could be regarded as the criterions in classification between the family Trichodinidae and Urceolariida, and four regions including Helix E10-1, Helix 29, Helix 43, and Helix 45-Helix 46 could be as criterions in classification between the genus Trichodinella and Trichodina in family Trichodinidae. After the analysis of common structural feature within the Mobilida, it was found that the secondary structure of V6 could prove the family Urceolariidae primitive status.

Phylogenetic analyses of Trichodinids (Ciliophora, Oligohymenophora) inferred from 18S rRNA gene sequence data.

Partial 18S rRNA gene sequences of the three trichodinids, namely Trichodina modesta Lom, 1970, Trichodina paraheterodentata Tang and Zhao 2012. and Trichodinella epizootica (Raabe 1950) Šrámek-Hušek, 1953, were acquired and used to construct phylogenetic trees. The results revealed that Trichodinella epizootica clustered with Trichodinella sp.