The primary structure of 28S ribosomal RNA constitutes a conserved core which is similar among most 23S-like rRNAs and expansion segments which occur at specific positions in the sequence. The expansion segments account for most of the size difference between prokaryotic (archaeal and eubacterial) and eukaryotic rRNAs and they exhibit a sequence variation which is unique among rRNAs. We have in...

In insects, ribosomal genes are usually detected in sex chromosomes, but have also or only been detected in autosomal chromosomes in some cases. Previous results from our research group indicated that in Bradysia hygida, nucleolus organizer regions were associated with heterochromatic regions of the autosomal C chromosome, using the silver impregnation technique. The present study confirmed thi...

Based upon the three experimentally derived models of E. coli 23S rRNA (1-3) and the partial model for yeast 26S rRNA (4), which was deduced by homology to E. coli, we derived a secondary structure model for Xenopus laevis 28S rRNA. This is the first complete model presented for eukaryotic 28S rRNA. Compensatory base changes support the general validity of our model and offer help to resolve wh...

Ribosomal DNA genes in many eukaryotes contain insertions of non-LTR retrotransposable elements belonging to the R2 clade. These elements persist in the host genomes by inserting site-specifically into multicopy target sites, thereby avoiding random disruption of single-copy host genes. Here we describe R9 retrotransposons from the R2 clade in the 28S RNA genes of bdelloid rotifers, small fresh...

The phylogenetic position of three taxa from two trematode genera, belonging to the subfamily Acanthostominae (Opisthorchioidea: Cryptogonimidae), were analysed using partial 28S ribosomal DNA (Domains 1-2) and internal transcribed spacers (ITS1-5.8S-ITS2). Bayesian inference and Maximum likelihood analyses of combined 28S rDNA and ITS1 + 5.8S + ITS2 sequences indicated the monophyly of the gen...

In this study the term 'rates of synthesis' does not refer to rates of transcription but to rates of accumulation of newly synthesized RNA. The rates of synthesis and half-lives of tRNA, 18S and 28S rRNA of 14-day and 17-day embryonic chick muscle were determined by following the accumulation of radioactive AMP in RNA after administration of [3H]8-adenosine to chick embryos and correcting for t...

Abstract Background Nematodes of the family Cosmocercidae (Ascaridomorpha: Cosmocercoidea) are mainly parasitic in digestive tract various amphibians and reptiles worldwide. However, our knowledge molecular phylogeny is still far from comprehensive. The phylogenetic relationships between other two families, Atractidae Kathlaniidae, superfamily Cosmocercoidea under debate. Moreover, systematic p...

Trematode cercariae are commonly found in many freshwater gastropods. These cercariae can serve to identify the occurrence of such trematodes as Centrocestus formosanus, Haplorchis taichui, Haplorchoides sp, and Stellantchasmus falcatus, which are important parasites in Chiang Mai Province, Thailand. As the species of these cercariae cannot be identified accurately based on morphology, this stu...

In this study, we use low-coverage shotgun sequencing of genomic DNA, commonly referred to as genome skimming, investigate the phylogenetic relationships fungus gnat genus Allodia Winnertz (Mycetophilidae, Mycetophilinae, Exechiini). Nineteen specimens, representing 16 in-group and three outgroup taxa, were successfully sequenced molecular markers both mitochondrial nuclear origin retrieved. Th...