We detected Neobenedenia girellae infections in 40 species belonging to 12 families of imported marine ornamental fish from a public aquarium the Mexican state Yucatan. A total 348 specimens were examined for monogeneans January 2018 December 2020. Monogeneans corroborated morphologically and molecularly with partial sequence 28S (region D1–D3) ribosomal DNA analyzed molecular phylogenetic cont...

Eukaryote ribosomal RNAs (rRNAs) have expanded in the course of phylogeny by addition of nucleotides in specific insertion areas, the expansion segments. These number about 40 in the larger (25-28S) rRNA (up to 2,400 nucleotides), and about 12 in the smaller (18S) rRNA (<700 nucleotides). Expansion of the larger rRNA shows a clear phylogenetic increase, with a dramatic rise in mammals and espec...

Schistosoma species have traditionally been arranged in groups based on egg morphology, geographical origins, and the genus or family of snail intermediate host. One of these groups is the 'S. indicum group' comprising species from Asia that use pulmonate snails as intermediate hosts. DNA sequences were obtained from the four members of this group (S. indicum, S. spindale, S. nasale and S. inco...

A fraction of the ribosomal 28S genes in some insects are interrupted at specific sites by insertion elements R1 and R2 (also called Type I and II). These elements contain long open-reading frames with homology to reverse transcriptase. We have identified in the silkmoth, Bombyx mori, copies of these elements which have inserted into sites outside the ribosomal DNA (rDNA) units. The 3' ends of ...

Ribosomes of all eukaryotes contain a single molecule of 5S, 18S, and 28S RNA. In the frog Xenopus laevis the genes which code for 18S and 28S RNA are located in the nucleolar organizer, but these genes are not linked to the 5S RNA genes. Therefore the synthesis of the three ribosomal RNAs provides a model system for studying interchromosomal aspects of gene regulation. In order to determine if...

Rat and human ribosomal RNA gene fragments in supercoiled plasmids were examined for S1 nuclease hypersensitivity. In the transcribed portion of genes the number and distribution of S1 sites were found to be species specific. No S1 sites were detected in the promoter regions. In the nontranscribed spacer (NTS), downstream of the 3' end of 28S RNA gene, S1 sites appear to be conserved in rat and...

Introduction Scale insects (Hemiptera: Coccomorpha) feed on a wide variety of agricultural crops and forest ornamental trees worldwide. These pest damage plants not only by causing sap loss but also reducing the plant's photosynthetic activity. This is because honeydew they produce acts as substrate for mold, which covers leaf surfaces. In last decades, several outbreaks Physokermes spp . (soft...

background: the present study was carried out to detect the infection of larval stages of trichobilharzia species in the snail lymnaea auricularia in northwestern iran based on dna analysis. methods: a total number of 320 snails of l. auricularia were sampled from four water-bodies located in the suburb of urmia city, north west iran, during may to november 2011. the snails were first microscop...

Haptophyta encompasses more than 300 species of mostly marine pico- and nanoplanktonic flagellates. Our aims were to investigate the Oslofjorden haptophyte diversity and vertical distribution by metabarcoding, and to improve the approach to study haptophyte community composition, richness and proportional abundance by comparing two rRNA markers and scanning electron microscopy (SEM). Samples we...

California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) are each believed to host distinct hookworm species (Uncinaria spp.). However, a recent morphometric analysis suggested that a single species parasitizes multiple pinniped hosts, and that the observed differences are host-induced. To explore the systematics of these hookworms and test these competing hypo...