Tetranychid mites are serious agricultural pests. Identification of species in the Tetranychidae is hampered by their close morphological similarities, especially for species within the genus Tetranychus. In this study, we examined the relationships of nine agriculturally important species in the Tetranychidae from China based on mitochondrial (cytochrome c oxidase subunit 1) and nuclear (inter...

Restriction fragment length polymorphism (RFLP) analysis was performed on the internal transcribed spacer regions of 204 Sporothrix schenckii isolates and on one strain each of the related fungi, S. schenckii var. luriei, S. curviconia, S. inflata and Ceratocystis stenoceras. S. schenckii isolates, which have been collected from around the world, have already been typed according to their mitoc...

Rare individuals of Xenopus laevis exhibit frequent initiation of transcription in the spacers of oocyte ribosomal DNA (rDNA). Using electron microscopy we have characterized spacer transcription in such an individual and have confirmed that the sites of transcription initiation correspond to the imperfectly duplicated promoters ("Bam islands") present in the X. laevis rDNA spacer. We have clon...

In this study, we report the cloning and nucleotide sequence of PCR-generated 5S rDNA from the Tilapiine cichlid fish, Oreochromis niloticus. Two types of 5S rDNA were detected that differed by insertions and/or deletions and base substitutions within the non-transcribed spacer (NTS). Two 5S rDNA loci were observed by fluorescent in situ hybridization (FISH) in metaphase spreads of tilapia chro...

We determined the nucleotide sequence of a D. melanogaster ribosomal DNA spacer. Sequences of various portions of different cloned ribosomal spacers have been previously reported. We extend the analysis to cover the entire nontranscribed and external transcribed regions. Comparison to other cloned ribosomal DNA gene units of this species confirms a conserved general organization of the ribosoma...

background : haemonchosis has a negative effect on the farming industry throughout the world, especially in the tropic and sub-tropic countries. the present study was carried out to differentiate haemonchus species from its main hosts in iran, including sheep, goat and camel.   methods: the identification took place based on the morphometrics of the spic-ules and molecular characters. two hundr...