Ticks are arthropod ectoparasites of importance for public and veterinary health. The understanding of tick oogenesis and embryogenesis could contribute to the development of novel control methods. However, to date, studies on the temporal dynamics of proteins during ovary development were not reported. In the present study we followed protein profile during ovary maturation. Proteomic analysis of ovary extracts was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using shotgun strategy, in addition to dimethyl labelling-based protein quantification. A total of 3,756 proteins were identified, which were functionally annotated into 30 categories. Circa 80% of the annotated proteins belong to categories related to basal metabolism, such as protein synthesis and modification machineries, nuclear regulation, cytoskeleton, proteasome machinery, transcriptional machinery, energetic metabolism, extracellular matrix/cell adhesion, immunity, oxidation/detoxification metabolism, signal transduction, and storage. The abundance of selected proteins involved in yolk uptake and degradation, as well as vitellin accumulation during ovary maturation, was assessed using dimethyl-labelling quantification. In conclusion, proteins identified in this study provide a framework for future studies to elucidate tick development and validate candidate targets for novel control methods.

No abstract

No abstract

The ticks Rhipicephalus appendiculatus and Rhipicephalus sanguineus are the main vectors of Theileria parva and Babesia spp. in cattle and dogs, respectively. Due to their impact in veterinary care and industry, improved methods against R. appendiculatus and R. sanguineus parasitism are under development, including vaccines. We have previously demonstrated the induction of a cross-protective humoral response against Rhipicephalus microplus following vaccination with recombinant glutathione S-transferase from Haemaphysalis longicornis tick (rGST-Hl), suggesting that this protein could control tick infestations. In the present work, we investigated the effect of rGST-Hl vaccine against R. appendiculatus and R. sanguineus infestation in rabbits. In silico analysis revealed that GST from H. longicornis, R. appendiculatus and R. sanguineus have >80% protein sequence similarity, and multiple conserved antigenic sites. After the second vaccine dose, rGST-Hl-immunized rabbits showed elevated antibody levels which persisted until the end of experiment (75 and 60 days for R. appendiculatus and R. sanguineus, respectively). Western blot assays demonstrated cross-reactivity between anti-rGST-Hl antibodies and native R. appendiculatus and R. sanguineus GST extracts from ticks at different life stages. Vaccination with rGST-Hl decreased the number, weight, and fertility of engorged R. appendiculatus adults, leading to an overall vaccine efficacy of 67%. Interestingly, histological analysis of organ morphology showed damage to salivary glands and ovaries of R. appendiculatus adult females fed on vaccinated animals. In contrast, rGST-Hl vaccination did not affect R. appendiculatus nymphs, and it was ineffective against R. sanguineus across the stages of nymph and adult. Taken together, our results show the potential application of rGST-Hl as an antigen in anti-tick vaccine development, however indicating a broad difference in efficacy among tick species.

No abstract

No abstract

No abstract

Introduction:Ticks are hematophagous ectoparasites that cause significate economical losses. Acaricide application is the main method to tick control. However, it causes environmental contamination and selects resistant ticks. The immunological control represents a suitable method to replace or complement acaricide application. During its life cycle, female ticks ingest large amounts of blood, which contains toxic components able to damage biomolecules. Understanding which molecular mechanisms and proteins are involved in avoid damages caused by blood intake in ticks and other hematophagous arthropods could help to found potential candidate antigens to compose an anti-tick vaccine. Review: Hemoglobin comprises almost 20% of mammalian blood proteins, its hydrolysis during tick digestion increases total free heme that can potentially generate reactive oxygen species (ROS), which easily oxidize lipids, proteins and DNA, modifying they structure and function. Lipids are more susceptible to high ROS levels. It can lead to membrane instability and cell death. Protein modifications caused by ROS can promote the protein loss of function and cell disturbance, however, it can also work as post-translational modifications, acting in cell signaling processes. DNA presents more efficient protective mechanisms against ROS, but damages can lead to double helix rupture. Oxidative stress is defined as a disturbance in the balance between the production and elimination of ROS, in favor of ROS production, leading to a disruption in redox homeostasis and/or molecular damage. Despite the well-recognized heme oxidative power and its already demonstrated cytotoxicity, ticks are able to feed on blood, controlling the redox homeostasis without causing oxidative stress. This occurs because ticks developed physiological adaptations to transport, store, metabolize and secrete toxic components from the diet. The strategies, such as heme compartmentalization in specialized organelles, and heme and iron carrying proteins are shared with most of other hematophagous. Interesting, heme degradation, a mechanism commonly described in hematophagous arthropods, showed to be absent in ticks. Moreover, there is a lack of key enzymes from the heme degradation pathway in tick genomes. As expected, antioxidant enzymes are often involved in homeostasis redox control. They act in a convenient way, eliminating physiological and non-physiological produced ROS. Despite their essential role in nonhematophagous organisms, antioxidant enzymes were associated with blood ingestion during arthropod hematophagous process, demonstrating their role in avoiding oxidative stress caused by blood intake. Catalase showed to be essential to heme detoxification in Rhipicephalus microplus tick, and diverse antioxidant enzymes are up-regulated after blood intake in a variety of hematophagous parasites. If in one hand ROS is responsible to cell damage and oxidative stress, on the other hand, several works revealed the fundamental role of ROS in cell signaling and function, demon...