Assessment and partial purification of serine protease inhibitors from Rhipicephalus (Boophilus) annulatuslarvae

Expression and function assessment of two serpin-type serine protease inhibitors from Haemaphysalis doenitzi

Serine protease inhibitors (serpins) in ticks are implicated in the modulation of the vertebrate host response to the tick bite. Experimentally, it has been demonstrated that serpins interfere with tick-borne pathogen transmission. However, knowledge on serpins in the tick Haemaphysalis doenitzi is lacking. In this study, the expression of two serpin genes, named HDS1 and HDS2, were assessed in H. doenitzi, and their roles in immune regulation were further investigated. The expression of HDS1 and HDS2 showed no tissue specificity, with maximum expression levels detected in the hemolymph and salivary gland, respectively. Among the developmental stages, the highest expression of HDS1 and HDS2 were detected in larvae and adults, respectively. The recombinant protein rHDS1 displayed obvious inhibitory effects on trypsin and thrombin, whereas rHDS2 clearly inhibited thrombin only. In addition, rHDS1 and rHDS2 showed certain inhibitory activities against bacteria and fungi. The female engorgement body weight, female engorgement rate, and egg hatchability were significantly decreased after injection of double-stranded RNA (dsRNA) of HDS1 gene, whereas no significant effects were observed concerning the feeding period or attachment rate at 24 h after introduction via rabbit ears. When injected with dsRNA of HDS2 gene, no significant effect was observed on the attachment rate at 24 h after introduction into the rabbit ears, but the engorgement body weight and engorgement rate of female ticks were significantly decreased, and no egg hatchment occurred. The above results contribute to better understanding the function of serpins in the development and innate immunity of H. doenitzi.

Seasonal distribution and faunistic of ticks in the Alashtar county (Lorestan Province), Iran

Introduction

Ticks are non-permanent obligate parasites that have considerable medical-veterinary and zoonosis importance. In this regard a study designed to investigate the distribution and fauna of ticks in the Alashtar county in Iran from April and March 2014.

Methods

Ticks were collected from livestock farms and facilities from selected rural and geographically location in the Alashtar county. Based morphological characteristics and reference identification keys, ticks were identified.

Results

A total of 549 ticks including 411 hard and 138 soft ticks were found. Ten tick species including Haemaphysalis concinna (0.36%), Haemaphysalis sulcata (0.36%), Hyalomma anatolicum (0.18%), Hyalomma dromedarii (0.18%), Hyalomma marginatum (1.45 %), Hyalomma schulzei (0.36%), Rhipicephalus annulatus (0.18%), Rhipicephalus bursa (28.1%), Rhipicephalus sanguineus (43.63%) and Argas persicus (25.2%) were identified. Tick seasonal distribution were 47.26%, 22.63%, 14.96% and 15.15% in the spring, summer, autumn and winter, respectively. The tick distribution was more from plain areas (64.96%) than the mountainous areas (35.04%). The rates of the tick contamination were 97.3% and 2.7% in the traditional and industrial livestock's, respectively. The livestock contamination ranks to the hard ticks were cattle (39.51%), sheep (34.15%) and goats (26.34 %), respectively. Chi-square analysis showed a significant difference among the seasonal distribution of the ticks in the spring, summer and autumn or winter; between the tick distribution in the plain and mountainous areas; and between the traditional and industrial livestock's tick contamination (P < 0.05).

Conclusion

Present study proves to change the traditional livestock's to the industrial livestock's. These findings highlight the importance of ticks and shows need to their control and tick pest management.

Identification and characterization of a cathepsin L-like cysteine protease from Rhipicephalus (Boophilus) annulatus

The tick Rhipicephalus (Boophilus) annulatus is one of the most important ectoparasites of bovines and is responsible for the transmission of different pathogens such as Babesia and Anaplasma. Cysteine proteases are involved in several host-tick interactions including invasion of host tissues, immune evasion, pathogen transmission, embryogenesis and blood digestion. In this study, the gene encoding R. annulatus cathepsin L-like enzyme (RaCL1) was cloned into pTZ57R/T vector, sequenced and analyzed using bioinformatics approaches. The nucleotide length of RaCL1 was 999 bp. Bioinformatics analysis showed 332 amino acids with an approximate molecular weight of 36.3 kDa which contained a signal peptide sequence (18 amino acids), pro-region (97 amino acids) and mature enzyme (217 amino acids). Multiple sequence alignment of the RaCL1 revealed high similarity to cathepsin L-like cysteine proteases from other tick species such as Rhipicephalus (Boophilus) microplus and Amblyomma variegatum. Based on bioinformatics analyses, results of this work suggest that RaCL1 can be a suitable candidate for the development of vaccine against R. annulatus.