Sequence analysis of the second internal transcribed spacer [ITS2] region of rDNA for species identification of trichostrongylus nematodes isolated from domestic livestock in Iran

Infectivity of herbivores with Trichostrongylus nematodes is widespread in many countries, having a major economic impact on breeding, survivability, and productivity of domestic livestock. This study was carried out on Trichostrongylus species isolated from domestic livestock in order to develop an easy-to-perform method for species identification. Trichostrongylus isolates were collected from sheep, goat, cattle, and buffaloes in Khuzestan Province, southwest Iran. Primary species identification was carried out based on morphological characterization of male worms. PCR amplification of ITS2-rDNA region was performed on genomic DNA and the products were sequenced. Phylogenetic analysis of the nucleotide sequence data was conducted employing Bayesian Inference approach. Consequently, a restriction fragment length polymorphism [RFLP] profile was designed to differentiate Trichostrongylus species. A consensus sequence of 238 nucleotides was deposited in the GenBank for Iranian isolates of Trichostrongylus species including T. colubriformis, T. capricola, T. probolurus and T. vitrinus. The designated RFLP using restriction enzyme TasI could readily differentiate among species having different ITS2 sequence. The molecular analysis was in concordance with morphological findings. Phylogenetic analysis indicated a close relationship among the sequences obtained in this study and reference sequence of relevant species. ITS2-RFLP with TasI is recommended for molecular differentiation of common Trichostrongylus species

Morphological and morphometrical description of trichostrongylus species isolated from domestic ruminants in Khuzestan province, southwest Iran

Genus Trichostrongylus [Nematoda: Trichostrongylidae] is one of the most important zoonotic nematodes with wide geographic distribution in the world. The purpose of the present study was to describe morphological and morphometrical characteristics of male Trichostrongylus species, currently prevalent in domestic ruminants of Khuzestan Province, southwest Iran. Gastro-inetstinal organs of 1600 sheep, goats, cattle, and buffalos, slaughtered in Khuzestan Province, southwest Iran, were examined for infectivity with Trichostrongylus species. For examination and measurements of helminthes, Azo-carmine staining was performed, followed by camera lucida drawings of morphological characters and measurements of morphometrical criteria with a calibrated microscope. Using valid nematodes systematic keys, almost all the parasites were identified at the level of species. Overall, 114 animals were found infected with at least one species of Trichostrongylus. Considering morphlogifcal characteristics of male Trichostrongylus, six species were identified including T. colubriformis, T. vitrinus, T. probolorus, T. capricola, T. longispicularis and Trichostrongylus sp.. Although, compared to the previous decades, currently Trichostrongylus is much less prevalent in the domestic ruminants of the study area, but still different species occur in these animals

[Mutation screening of GJB2 and GJB6 and genetic linkage study of three prevalent DFNB loci in Iranian families with autosomal recessive non-syndromic hearing loss]

The incidence of prelingual hearing loss [HL] is about 1 in 1000 neonates of which, more than 60% of cases are inherited. Non-syndromic HL [NSHL] is extremely heterogeneous: more than 100 loci have been identified. The most common form of NSHL is the autosomal recessive form [ARNSHL]. Here, we have investigated CX26 [GJB2] and CX30 [GJB6] gene mutation and linkage analysis of 3 known loci in Iranian families. A cohort of 36 big ARNSHL pedigrees from 7 provinces of Iran was investigated. All of the families were examined for the presence of GJB2 and GJB6 [del D13S1830 and del D13S1854] mutations using direct sequencing and multiplex PCR, respectively. The negative mutations pedigrees for the above-mentioned mutations, were then tested for the linkage to the 3 known loci, including DFNB3[MYO7A], DFNB4[SLC26A4] and DFNB7/11[TMC1], using STR markers and conventional PCR and PAGE. Six families had GJB2 mutations. No GJB6 mutation was found. Totally, 3 families showed linkage to DFNB4 and 1 family was linked to DFNB7/11. DFNB1 [GJB2] and DFNB4 are the main causes of ARNSHL in our study samples and GJB6 mutations are apparently absent in the Iranian population