Factor C is a multi-domain serine protease which recognizes Gram-negative bacteria via binding to lipopolysaccharides and triggers hemolymph clotting cascade in the horseshoe crab. A closely related molecule was also found to be present in the genome of the tick Ixodes scapularis. In this work, the full sequence of Factor C ortholog from Ixodes ricinus (IrFC) was determined. IrFC is mainly expressed in tick hemocytes and the heavy chain of the activated molecules is present in tick hemolymph as confirmed by Western blotting with antibodies raised against recombinant fragments of IrFC. The function of the IrFC in tick innate immunity was assessed using its silencing by RNA interference.

I describe procedures for the introduction of Borrelia burgdorferi, the spirochetal agent of Lyme disease, into larval and nymphal stage of the tick vector, Ixodes ricinus. The goal of this Mgr. Thesis is to find an optima system, that would reliably and reproducibly allow the infection of large numbers of ticks with the Lyme disease spirochete.

Ticks are blood feeding parasites that secrete a number of immunomodulatory factors to evade host immune response. The aim of this study was to prepare a tick salivary protein with anti-chemokine activity and to observe the influence of salivary gland extrakt on neutrophile´s chemotaxis.

Univ Arizona, Dept Mol & Cellular Biol

As metaloproteases (MPs) são proteínas que participam em diversos processos fisiológicos e patológicos. Neste trabalho, relatamos a identificação de MPs em três carrapatos de importância econômica: Ixodes persulcatus (Ip-MPs), Rhipicephalus sanguineus (Rs-MPs) e Rhipicephalus microplus (BrRm-MPs). O perfil transcricional em vários tecidos e fases de vida mostra que MPs são transcritas em glândula salivar durante a alimentação de fêmeas e não são transcritos no macho (com exceção de uma MP, BrRm-MP4) e ovos, o que sugere que esta família da proteínas são componentes funcionais necessários para interferir nas defesas do hospedeiro, apoiando o processo de hematofagia. A presença de um sítio de ligação de zinco, uma dobra“Met-turn” e um domínio rico em cisteína na região C-terminal indica que todas os transcritos obtidos codificam para a família de MPs reproplisina (metzincina). Uma das MPs de R. microplus (BrRm-MP4) foi selecionada para uma investigação mais aprofundada quanto ao potencial como um antígeno vacinal, devido ao seu padrão de transcrição ubíquos e devido àprevisão in silico de epítopos imunogênicos, em comparação com as demais MPs identificadas. BrRm-MP4 recombinante (rBrRm-MP4) foi expressa em Escherichia coli e testadas como um antígeno contra infestação de R. microplus. Imunoblot mostrou que o soro de bovinos imunizados com rBrRm-MP4 reconhece BrRm-MP4 da glândula salivar, ovário e larvas de R. microplus. Comparando com o controle, a vacinação com rBrRm-MP4 proporcionou uma redução de 43% no número de fêmeas adultas, redução de 14,80% na postura de ovos e redução de 17,53 % na capacidade de eclosão da larva, realizando um proteção total de 60% estatisticamente significativa. Os resultados indicam que rBrRm-MP4 é um potencial candidato a ser incluído como imunógeno em uma vacina anti-carrapato. / Metalloproteases (MPs) are proteins participating in several physiological and pathological processes. Here, we report the identification of MPs in three economically important ticks: Ixodes persulcatus (Ip-MPs), Rhipicephalus sanguineus (Rs-MPs) and Rhipicephalus microplus (BrRm-MPs). Transcriptional profile in various tissues and life stages revealed the presence of all MPs transcripts in salivary glands during feeding stages and absence in males (except one MP, BrRm-MP4) and eggs, suggesting this family proteins are functional components required to interfere with host defenses, supporting tick hematophagy. The presence of a zinc binding site, a “Met-turn” and C-terminal cysteine rich domain indicates all obtained transcripts encode for proteins belonging to the reproplysin (metzincin) family of MPs. A R. microplus MP (BrRm-MP4) was selected for further investigation concerning its potential as a vaccinal antigen due to its ubiquitous transcription pattern and in silico prediction of immunogenic epitopes, comparing to other obtained MPs. Recombinant BrRm-MP4 (rBrRm-MP4) was expressed in Escherichia coli and tested as an immune-protective antigen against R. microplus infestation. Immunoblot showed specific antibodies against rBrRm-MP4 in immunized calves sera. Sera from immunized calves recognized BrRm-MP4 in R. microplus salivary gland, ovary and larvae. Comparing to ticks reared non-vaccinated calves, rBrRm-MP4 provided 43% reduction in adult female number, 14.80% reduction in egg laying and 17.53% reduction in larva hatching capacity, performing an overall 60% statistically significant protection. We assume rBrRm-MP4 is a potential candidate to be included as immmunogen for further development in an anti-tick vaccine.

Lyme disease is one of the most common vector-borne diseases around the world, and the numbers of reported cases are quickly rising. Ixodes ticks are the principal vectors, while Borrelia burgdorferi sensu lato genospecies are the etiological agents of the disease. Climate change, namely global warming, and habitat modification, namely forest fragmentation, are hypothesized to play an active role in this rise in reported cases. An analysis of the primary literature, specifically of studies focused on North America and Europe, was conducted in order to investigate these hypotheses. These studies show that global warming has precipitated a growth in tick populations as well as a northward tick migration, thereby increasing the risk of Lyme disease in emergent and endemic areas alike, for Borrelia spirochetes quickly infect naïve tick populations. Furthermore, published studies support the idea that forest fragmentation near human population centers has also increased the risk of Lyme disease in North America, for edge habitats provide suitable conditions for ticks and provide edible vegetation for the animals on which ticks feed, animals which also serve as hosts for B. burgdorferi sensu lato. In contrast, a decrease in fragmentation was found to facilitate tick invasion and establishment in Europe. These studies demonstrate that anthropogenic habitat modifications of varying types can affect ticks and their host populations and increase the risk of Lyme disease near human population centers. However, more research needs to be done to truly understand the different factors that are precipitating the rising number of cases of Lyme disease since there are significant interactions between climate change, habitat modification, and other drivers not examined here. Furthermore, understanding how these drivers function in specific geographic locations can help scientists and public officials tailor local public health measures appropriately. Finally, researchers and pharmaceutical companies must develop a safe, long-lasting, and effective vaccine against the Lyme disease spirochete, for there is not one currently available. Although easily treatable if diagnosed early, Lyme disease can progress to debilitating disease. Unfortunately, the risk of contracting this illness is currently rising and will continue to rise unless effective preventative measures are employed.

<p>Ticks are vectors for a larger number of viruses and bacteria than all other arthropod taxa, including mosquitoes. In Europe is it foremost Borrelia spirochetes and the Flavivirus Tick-borne Encephalitis virus that cause disease in humans. In this study, the tick species <em>Ixodes uriae</em> has been studied. <em>I.</em><em> uriae</em> have a circumpolar distribution in both hemisphere and can be found both in Arctic and Antarctica. I collected ticks from Magellanic penguins in south Chile and analyzed them to see if they carry <em>Borrelia</em> spirochetes or Flavivirus. Totally were 218 ticks collected from 165 controlled penguins. All ticks were collected from adult penguins and the parasitizing ticks were all found in the auditory meatus which is a new phenomena compared to earlier studies. Both <em>Borrelia</em> spirochetes and Flavivirus were found in the collected ticks using PCR techniques. This is an interesting result since not much research has been performed in this geographical area before. Until date there is only one species of <em>Borrelia</em> (<em>Borrelia</em> <em>garinii</em>) found in <em>I.</em><em> uriae</em> on the southern hemisphere and new Flavivirus is regularly found around the world.  Unfortunately we have not been able to determine species of the <em>Borrelia </em>spirochetes or Flavivirus so far but this work will be continued. <strong></strong></p>

Ixodes ricinus is the main vector of Lyme borreliosis and Tick-borne encephalitis in Europe. Repellents provide a practical means of protection against tick bites and can therefore reduce transmission of tick-borne diseases. In laboratory tests, pieces of cloth treated with MyggA Natural® (a commercial insect repellent) or with the essential oils of Corymbia citriodora (30%), Lavandula angustifolia (1 and 30%), Pelargonium graveolens (1 and 30%), Hyptis suaveolens (10%), Salvadora persica, Pistacia atlantica, Juniperus phoenicea (20%) and methyl jasmonate (MJ) (0.5%, 1.0%, 2.0% and 5.0%) showed strong repellent activity against I. ricinus nymphs. In a tick-infested woodland in east-central Sweden, we tested by randomized, standardised methodology the potential anti-tick repellent activity of MyggA Natural® (roll-on), two concentrations of MyggA Natural® spray, RB86 (a commercially available insect repellent for horses), the essential oil of C. citriodora and three concentrations of MJ. Each substance was dissolved in acetone and applied separately to 1 m2 cloths which were then pulled over vegetation. Nymphal tick numbers on the cloths were recorded at 10-m intervals and differed significantly between treated cloths and the untreated control and also between collectors. Volatile compounds from fresh and dried leaves of H. suaveolens and the essential oils of H. suaveolens (from Laos and Guinea Bissau) and S. persica, P. atlantica and J. phoenicea (from Libya) were collected by solid phase micro-extraction (SPME) and the constituents were identified by gas chromatography - mass spectrometry (GC-MS). Two main sesquiterpene hydrocarbons in the H. suaveolens oil were β-caryophyllene and humulene. These were modified by oxidation and sulphidation to obtain effective tick repellent compounds with lower volatility. In all three oils from Libyan plants the main monoterpene hydrocarbons were α-pinene, sabinene, β-pinene, myrcene, α-phellandrene, 4-carene, β-phellandrene and γ-terpinene. The selected plant species contained numerous volatiles known to have insecticidal, acaricidal, and/or insect repellent properties.

Ticks are vectors for a larger number of viruses and bacteria than all other arthropod taxa, including mosquitoes. In Europe is it foremost Borrelia spirochetes and the Flavivirus Tick-borne Encephalitis virus that cause disease in humans. In this study, the tick species Ixodes uriae has been studied. I. uriae have a circumpolar distribution in both hemisphere and can be found both in Arctic and Antarctica. I collected ticks from Magellanic penguins in south Chile and analyzed them to see if they carry Borrelia spirochetes or Flavivirus. Totally were 218 ticks collected from 165 controlled penguins. All ticks were collected from adult penguins and the parasitizing ticks were all found in the auditory meatus which is a new phenomena compared to earlier studies. Both Borrelia spirochetes and Flavivirus were found in the collected ticks using PCR techniques. This is an interesting result since not much research has been performed in this geographical area before. Until date there is only one species of Borrelia (Borrelia garinii) found in I. uriae on the southern hemisphere and new Flavivirus is regularly found around the world.  Unfortunately we have not been able to determine species of the Borrelia spirochetes or Flavivirus so far but this work will be continued.

Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Feb. 08, 2010). Includes bibliographical references (p. 81-94).