RNA activation in ticks.

RNA activation (RNAa) is a burgeoning area of research in which double-stranded RNAs (dsRNAs) or small activating RNAs mediate the upregulation of specific genes by targeting the promoter sequence and/or AU-rich elements in the 3'- untranslated region (3'-UTR) of mRNA molecules. So far, studies on the phenomenon have been limited to mammals, plants, bacteria, Caenorhabditis elegans, and recently, Aedes aegypti. However, it is yet to be applied in other arthropods, including ticks, despite the ubiquitous presence of argonaute 2 protein, which is an indispensable requirement for the formation of RNA-induced transcriptional activation complex to enable a dsRNA-mediated gene activation.

Localization of secreted ferritin (FER2) in the embryos of the tick Haemaphysalis longicornis.

Despite the absence of a blood meal, embryogenesis involves many processes that require nutrients and other essential elements, including iron. Due to the lack of an external source of these nutrients, these requirements are acquired maternally. Because of the toxic nature of iron, they are transferred through iron transport molecules such as secreted ferritin (FER2).

Ambivalent Roles of Oxidative Stress in Triangular Relationships among Arthropod Vectors, Pathogens and Hosts.

Blood-feeding arthropods, particularly ticks and mosquitoes are considered the most important vectors of arthropod-borne diseases affecting humans and animals. While feeding on blood meals, arthropods are exposed to high levels of reactive oxygen species (ROS) since heme and other blood components can induce oxidative stress. Different ROS have important roles in interactions among the pathogens, vectors, and hosts.

Relationship between hepatic grayish-white solid nodules in horses imported from Canada and larval infection.

Histopathological and genetic examinations were conducted on grayish-white solid hepatic nodules in 150 horses imported from Canada, in order to investigate larval infection. Ten of the 150 horses (6.7%) were diagnosed with alveolar hydatid disease.

The antiviral immunity of ticks against transmitted viral pathogens.

Ticks, being obligate hematophagous arthropods, are exposed to various blood-borne pathogens, including arboviruses. Consequently, their feeding behavior can readily transmit economically important viral pathogens to humans and animals. With this tightly knit vector and pathogen interaction, the replication and transmission of tick-borne viruses (TBVs) must be highly regulated by their respective tick vectors to avoid any adverse effect on the ticks' biological development and viability.

An Ixodes scapularis glutathione S-transferase plays a role in cell survival and viability during Langat virus infection of a tick cell line.

Ticks are important vectors of diseases affecting both humans and animals. To be an efficient vector, ticks have to survive infection by pathogens such as the Langat virus (LGTV). One method utilized by ticks is their complex antioxidant mechanism.

Expression analysis of glutathione S-transferases and ferritins during the embryogenesis of the tick .

In the tick life cycle, embryogenesis is the only stage of development wherein no blood meal is required. Nevertheless, even in the absence of a blood meal, which is the source of nutrients as well as the ferrous iron and heme that could cause oxidative stress in ticks, malondialdehyde (MDA) has been reported to increase during this period. Additionally, the knockdown of some oxidative stress-related molecules such as ferritin has resulted in abnormal eggs and embryonic death.

A Peroxiredoxin From the Tick Affects Langat Virus Replication in a Hamster Cell Line.

Ticks are hematophagous arthropods, and their blood feeding on vertebrate hosts is essential for their development. The vertebrate blood contains high levels of free iron that can react with oxygen in ticks, resulting in the production of hydrogen peroxide (HO), one of the reactive oxygen species. Peroxiredoxins (Prxs), HO-scavenging enzymes, take on an important role in the ticks' oxidative stress coping mechanism.

Characterization of an iron-inducible Haemaphysalis longicornis tick-derived promoter in an Ixodes scapularis-derived tick cell line (ISE6).

Background: Ticks are important vectors of disease-causing pathogens. With the rise of resistance to chemical acaricides, alternative methods in tick control are warranted. Gene manipulation has been successful in controlling mosquitoes and mosquito-borne diseases and is now looked upon as a candidate method to control ticks and tick-borne pathogens.

The case for oxidative stress molecule involvement in the tick-pathogen interactions -an omics approach.

The blood-feeding behavior of ticks has resulted in them becoming one of the most important vectors of disease-causing pathogens. Ticks possess a well-developed innate immune system to counter invading pathogens. However, the coevolution of ticks with tick-borne pathogens has adapted these pathogens to the tick's physiology and immune response through several mechanisms including transcriptional regulation.

A Continuing Exploration of Tick-Virus Interactions Using Various Experimental Viral Infections of Hard Ticks.

To fully unravel the ixodid ticks' role as vectors of viral pathogens, their susceptibility to new control measures, and their ability to develop acaricide resistance, acclimatization of ticks under laboratory conditions is greatly needed. However, the unique and complicated feeding behavior of these ticks compared to that of other hematophagous arthropods requires efficient and effective techniques to infect them with tick-borne viruses (TBVs). In addition, relatively expensive maintenance of animals for blood feeding and associated concerns about animal welfare critically limit our understanding of TBVs.

Induction of intracellular ferritin expression in embryo-derived Ixodes scapularis cell line (ISE6).

Iron is a very important nutrient for cells; however, it could also cause fatal effects because of its capability to trigger oxidative stress. Due to high exposure to iron from their blood diet, ticks make use of several mechanisms to cope up with oxidative stress. One mechanism is iron sequestration by ferritin and its control protein (IRP).

Hemolymph defensin from the hard tick Haemaphysalis longicornis attacks Gram-positive bacteria.

Ticks are key vectors of some important diseases of humans and animals. Although they are carriers of disease agents, the viability and development of ticks are not harmed by the infectious agents due to their innate immunity. Antimicrobial peptides directly protect hosts against pathogenic agents such as viruses, bacteria, and parasites.

Characterization and expression analysis of a newly identified glutathione S-transferase of the hard tick Haemaphysalis longicornis during blood-feeding.

Background: Ticks are obligate hematophagous parasites important economically and to health. Ticks consume large amounts of blood for their survival and reproduction; however, large amounts of iron in blood could lead to oxidative stress. Ticks use several molecules such as glutathione S-transferases (GSTs), ferritins, and peroxiredoxins to cope with oxidative stress.

Immunofluorescent detection in the ovary of host antibodies against a secretory ferritin injected into female Haemaphysalis longicornis ticks.

Due to the continuous threat of ticks and tick-borne diseases to human and animal health worldwide, and the drawbacks of chemical acaricide application, many researchers are exploring vaccination as an alternative tick control method. Earlier studies have shown that host antibodies can circulate in the ticks, but it has not been confirmed whether these antibodies can be passed on to the eggs. We previously reported that ticks infesting rabbits immunized with a recombinant secretory ferritin of Haemaphysalis longicornis (HlFER2) had reduced egg production and hatching.

Synchronous Langat Virus Infection of Haemaphysalis longicornis Using Anal Pore Microinjection.

The tick-borne encephalitis virus (TBEV) serocomplex of flaviviruses consists of arboviruses that cause important diseases in animals and humans. The transmission of this group of viruses is commonly associated with tick species such as Ixodes spp., Dermacentor spp.

Induction of gene silencing in Haemaphysalis longicornis ticks through immersion in double-stranded RNA.

The continuous emergence of tick-borne diseases and chemical acaricide-resistant tick strains necessitates the development of new and more effective control strategies. RNA interference through the injection of double-stranded RNA (dsRNA) has been a very useful tool in tick research for evaluating gene function. However, this technique can be sophisticated due to the required equipment and technique.

Virucidal activity of Haemaphysalis longicornis longicin P4 peptide against tick-borne encephalitis virus surrogate Langat virus.

Background: Longicin is a defensin-like peptide, identified from the midgut epithelium of hard tick Haemaphysalis longicornis. Several studies have already shown the antimicrobial and parasiticidal activities of longicin peptide and one of its synthetic partial analogs, longicin P4. In this study, longicin peptides were tested for potential antiviral activity against Langat virus (LGTV), a tick-borne flavivirus.