Common dace (Leuciscus leuciscus) - A new host of the myxozoan fish parasite, Myxobolus elegans (Cnidaria: Myxozoa) - Short communication

This paper reports the detection of the myxozoan species Myxobolus elegans Kashkovsky 1966 in common dace (Leuciscus leuciscus) that has not been previously listed as its host. The problem of differentiation of phenotypically similar Myxobolus species is addressed. During parasitological survey of common dace from the desalinated part of the Gulf of Finland at the city of Sestroretsk, Russia, numerous oval-shaped plasmodia, 0.2-0.4 mm in size, filled with Myxobolus spores were found on the gills. Pear-shaped myxospores were 15.4 (14.8-16.0) x 10.2 (9.6-10.9) mu m in size with a rib on each valve. On the basis of spore morphology, the species appeared to be similar to M. elegans and Myxobolus hungaricus Jaczo, 1940. In order to identify the species, molecular genetic analysis was performed, and the species was identified on the basis of morphological characteristics and 18S rDNA data. The results obtained indicate that the Myxobolus species observed on the gills of dace is M. elegans. Thus, common dace is another valid host of M. elegans besides the type host, ide (Leuciscus idus)

Morphological Differentiation, Mitochondrial and Nuclear DNA Variability Between Geographically Distant Populations of Daphnia galeata and Daphnia cucullata (Anomopoda, Daphniidae)

Несмотря на то, что представители р. Daphnia (Anomopoda, Daphniidae) являются одними из наиболее распространенных водных беспозвоночных и используются в качестве модельных организмов в таксономических, экологических и эволюционных исследованиях, их систематика остается весьма запутанной. Настоящее исследование посвящено изучению морфологической дифференциации и генетической изменчивости географически удаленных популяций сестринских видов Daphnia galeata Sars, 1864 и Daphnia cucullata Sars, 1862 (Anomopoda, Daphniidae) из пресноводной части Балтийского моря - Куршского залива (Россия, Калининградская область) и Новосибирского водохранилища (Россия, Новосибирская область). Морфологическая дивергенция между видами и их популяциями оценивалась по диагностическим признакам и на основании анализа изменчивости формы тела по набору морфометрических признаков. Самыми изменчивыми были признаки, характеризующие форму головы, шлема и хвостовой иглы. Реконструкция филогенетических отношений между видами выполнена на основе изменчивости 16S и 12S генов митохондриальной ДНК и фрагмента ITS2 ядерной ДНК. Дивергенция между видами D. galeata и D. cucullata на основе генов митохондриальной ДНК была значительной и свидетельствует об их монофилетическом происхождении, тогда как внутривидовые генетические дистанции оцениваются как незначительные.Although members of genus Daphnia (Anomopoda, Daphniidae) are the most common water invertebrates and are considered as model organisms for many taxonomic, ecological and evolutionary studies their systematics remains unresolved. Here, morphological differentiation and genetic polymorphism between the geographically distant populations of the sister species Daphnia galeata Sars, 1864 and Daphnia cucullata Sars, 1862 in the Curonian Lagoon, a large shallow freshwater lagoon of the Baltic Sea (Russia, Kaliningrad Oblast) and Novosibirsk Reservoir (Russia, Novosibirsk Oblast) are presented. The divergence between species and their populations was analyzed based on traditional morphological traits and a large set of morphometric traits describing the body shape. The traits describing the shape of head and helmet, and spine were the most variable morphological characters. Phylogenetic relationships between species and populations were constructed based on variation in mitochondrial 16S and 12S rRNA genes and nuclear ITS2 rDNA sequences. The mitochondrial DNA divergence between D. galeata and D. cucullata species was significant and reflected their monophyletic origin, whereas intraspecific genetic distances are estimated as insignificant

Evidence of dispersal between the Yenisei and the Lena river basins during the late Pleistocene within the whitefish (Coregonus lavaretus pidschian) complex

The Coregonus lavaretus (Linnaeus, 1758) complex is a morphologically and genetically diverse group of whitefish. Its taxonomic structure has been controversial for almost a century. At least 25 forms of C. lavaretus have been described in Siberia, but there is still no consensus on their intraspecific structure and taxonomy. Coregonus lavaretus pidschian (Gmelin, 1789) was described as a subspecies of C. lavaretus. Recently, it was assumed that this subspecies is also a complex. The purpose of this study was to compare the distributions of pidschian-like whitefish haplotypes in two basins of large Siberian rivers, Yenisei and Lena, and to assess the gene flow between basins of these rivers, which were connected after the last glaciation. The sequence of the following mitochondrial DNA genes, 16S rRNA (partial), tRNA-Leu (full), NADH dehydrogenase subunit 1 (full), tRNA-Ile (full), and tRNA-Gln (partial), were used for the inference of intraspecific genetic structure of C. l. pidschian. Whitefish haplotypes were clustered into two groups according to their distribution between two large Siberian river basins; however, there were shared haplotypes indicating events of migration and hybridization, which could occur when Bolshoi Yenisei and Lena river systems were connected after the last glaciation (the Late Pleistocene).info:eu-repo/semantics/acceptedVersio

Morphological Differentiation, Mitochondrial and Nuclear DNA Variability Between Geographically Distant Populations of Daphnia galeata and Daphnia cucullata (Anomopoda, Daphniidae)

Несмотря на то, что представители р. Daphnia (Anomopoda, Daphniidae) являются одними из наиболее распространенных водных беспозвоночных и используются в качестве модельных организмов в таксономических, экологических и эволюционных исследованиях, их систематика остается весьма запутанной. Настоящее исследование посвящено изучению морфологической дифференциации и генетической изменчивости географически удаленных популяций сестринских видов Daphnia galeata Sars, 1864 и Daphnia cucullata Sars, 1862 (Anomopoda, Daphniidae) из пресноводной части Балтийского моря - Куршского залива (Россия, Калининградская область) и Новосибирского водохранилища (Россия, Новосибирская область). Морфологическая дивергенция между видами и их популяциями оценивалась по диагностическим признакам и на основании анализа изменчивости формы тела по набору морфометрических признаков. Самыми изменчивыми были признаки, характеризующие форму головы, шлема и хвостовой иглы. Реконструкция филогенетических отношений между видами выполнена на основе изменчивости 16S и 12S генов митохондриальной ДНК и фрагмента ITS2 ядерной ДНК. Дивергенция между видами D. galeata и D. cucullata на основе генов митохондриальной ДНК была значительной и свидетельствует об их монофилетическом происхождении, тогда как внутривидовые генетические дистанции оцениваются как незначительные.Although members of genus Daphnia (Anomopoda, Daphniidae) are the most common water invertebrates and are considered as model organisms for many taxonomic, ecological and evolutionary studies their systematics remains unresolved. Here, morphological differentiation and genetic polymorphism between the geographically distant populations of the sister species Daphnia galeata Sars, 1864 and Daphnia cucullata Sars, 1862 in the Curonian Lagoon, a large shallow freshwater lagoon of the Baltic Sea (Russia, Kaliningrad Oblast) and Novosibirsk Reservoir (Russia, Novosibirsk Oblast) are presented. The divergence between species and their populations was analyzed based on traditional morphological traits and a large set of morphometric traits describing the body shape. The traits describing the shape of head and helmet, and spine were the most variable morphological characters. Phylogenetic relationships between species and populations were constructed based on variation in mitochondrial 16S and 12S rRNA genes and nuclear ITS2 rDNA sequences. The mitochondrial DNA divergence between D. galeata and D. cucullata species was significant and reflected their monophyletic origin, whereas intraspecific genetic distances are estimated as insignificant

List of conserved miRNAs identified in three Opisthorchiidae species.

<p>List of conserved miRNAs identified in three Opisthorchiidae species.</p

Identification of microRNA Genes in Three Opisthorchiids

<div><p>Background</p><p><i>Opisthorchis felineus</i>, <i>O</i>. <i>viverrini</i>, and <i>Clonorchis sinensis</i> (family Opisthorchiidae) are parasitic flatworms that pose a serious threat to humans in some countries and cause opisthorchiasis/clonorchiasis. Chronic disease may lead to a risk of carcinogenesis in the biliary ducts. MicroRNAs (miRNAs) are small noncoding RNAs that control gene expression at post-transcriptional level and are implicated in the regulation of various cellular processes during the parasite- host interplay. However, to date, the miRNAs of opisthorchiid flukes, in particular those essential for maintaining their complex biology and parasitic mode of existence, have not been satisfactorily described.</p><p>Methodology/Principal Findings</p><p>Using a SOLiD deep sequencing-bioinformatic approach, we identified 43 novel and 18 conserved miRNAs for <i>O</i>. <i>felineus</i> (miracidia, metacercariae and adult worms), 20 novel and 16 conserved miRNAs for <i>O</i>. <i>viverrini</i> (adult worms), and 33 novel and 18 conserved miRNAs for <i>C</i>. <i>sinensis</i> (adult worms). The analysis of the data revealed differences in the expression level of conserved miRNAs among the three species and among three the developmental stages of <i>O</i>. <i>felineus</i>. Analysis of miRNA genes revealed two gene clusters, one cluster-like region and one intronic miRNA in the genome. The presence and structure of the two gene clusters were validated using a PCR-based approach in the three flukes.</p><p>Conclusions</p><p>This study represents a comprehensive description of miRNAs in three members of the family Opistorchiidae, significantly expands our knowledge of miRNAs in multicellular parasites and provides a basis for understanding the structural and functional evolution of miRNAs in these metazoan parasites. Results of this study also provides novel resources for deeper understanding the complex parasite biology, for further research on the pathogenesis and molecular events of disease induced by the liver flukes. The present data may also facilitate the development of novel approaches for the prevention and treatment of opisthorchiasis/clonorchiasis.</p></div

Genomic organization scheme of cluster-like regions miR-1/miR-133 in five flatworms.

<p>Designations are the same as in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003680#pntd.0003680.g003" target="_blank">Fig 3</a>.</p

Venn diagrams of the miRNAs sets.

<p>(A) conserved miRNAs in three opisthorchiid species, (B) O. <i>felineus</i> conserved miRNAs at different developmental stages, (C) novel miRNAs in the three opisthorchiid species, (D) O. <i>felineus</i> novel miRNAs at different developmental stages.</p

List of conserved miRNAs identified in different samples of <i>O</i>. <i>felineus</i>.

<p>List of conserved miRNAs identified in different samples of <i>O</i>. <i>felineus</i>.</p

Scheme of miRNA gene clusters in Platyhelminthes.

<p>(A) miR-71a/2 cluster group, (B) miR-71b/2 cluster group. Species designations: csi—C. sinensis, sma—S. mansoni, sja—S. japonicum, sme—S. mediterranea, hmi—H. microstoma, egr—E. granulosus, emu—E. multilocularis, gsa- G. salaris.</p