Abstract
Defensins are an important component of the innate immune system of ticks. These small peptides are produced by various genera of ticks, and expressed in various tissues. In this study we used RNA interference to silence the expression of the defensin varisin produced by the hemocytes of the American dog tick, Dermacentor variabilis. Ticks were injected with double stranded varisin RNA prior to being placed on a rabbit. After feeding, the ticks were removed, bled, and the hemolymph plasma and hemocytes separated. Hemocytes were screened for the presence (or absence) of both varisin transcript and peptide. Varisin peptide was below detectable levels and the transcript showed a greater than 99% knockdown. The antimicrobial activity of the hemolymph plasma was reduced 2–4 fold compared to that of control injected ticks indicating varisin accounts for a large portion of the antimicrobial activity of the hemolymph.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bartholomay LC, Fuchs JF, Cheng LL, Beck ET, Vizioli J, Lowenberger C, Christensen BM (2004) Reassessing the role of defensin in the innate immune response of the mosquito, Aedes aegypti. Insect Mol Biol 13:125–132
Brown RN, Lane RS, Dennis DT (2005) Geographic distributions of tick-borne diseases and their vectors. In: Goodman JL, Dennis DT, Sonenshine DE (eds) Tick-borne diseases of humans. ASM Press, Washington DC, pp 363–391
Bulet P, Hetru C, Dimarcq JL, Hoffmann D (1999) Antimicrobial peptides in insects; structure and function. Dev Comp Immunol 23:329–344
Bulet P, Charlet M, Hetru C (2003) Antimicrobial peptides in insect immunity. In: Ezekowitz RAB, Hoffmann JA (eds) Innate immunity. Humana Press Inc, Totowa, pp 89–107
Ceraul SM (2005) PhD dissertation. Department of Biological Sciences, Old Dominion University, Norfolk
Ceraul SM, Sonenshine DE, Hynes WL (2002) Resistance of the tick Dermacentor variabilis (Acari: Ixodidae) following challenge with the bacterium Escherichia coli (Enterobacteriales: Enterobacteriaceae). J Med Entomol 39:376–383
Ceraul SM, Sonenshine DE, Ratzlaff RE, Hynes WL (2003) An arthropod defensin expressed by the hemocytes of the American dog tick, Dermacentor variabilis (Acari: Ixodidae). Insect Biochem Mol Biol 33:1099–1103
Ceraul SM, Dreher-Lesnick SM, Gillespie JJ, Rahman MS, Azad AF (2007) New tick defensin isoform and antimicrobial gene expression in response to Rickettsia montanensis challenge. Infect Immun 75:1973–1983
Cociancich S, Bulet P, Hetru C, Hoffmann JA (1994) The inducible antibacterial peptides of insects. Parasitol Today 10:132–138
de la Fuente J, Almazan C, Blouin EF, Naranjo V, Kocan KM (2005) RNA interference screening in ticks for identification of protective antigens. Parasitol Res 96:137–141
de la Fuente J, Kocan KM, Almazan C, Blouin EF (2007) RNA interference for the study and genetic manipulation of ticks. Trends Parasitol 23:427–433
Eggenberger LR, Lamorreaux WJ, Coons LB (1990) Hemocytic encapsulation of implants in the tick, Dermacentor variabilis. Exp Appl Acarol 9:279–287
Gillespie JP, Kanost MR, Trenczek T (1997) Biological mediators of insect immunity. Annu Rev Entomol 42:611–643
Hynes WL, Ceraul SM, Todd SM, Seguin KC, Sonenshine DE (2005) A defensin-like gene expressed in the black-legged tick, Ixodes scapularis. Med Vet Entomol 19:339–344
Inoue N, Hanada K, Tsuji N, Igarashi I, Nagasawa H, Mikami T, Fujisaki K (2001) Characterization of phagocytic hemocytes in Ornithodoros moubata (Acari: Ixodidae). J Med Entomol 38:514–519
Johns R (2003) Tick immunology and its influence on vector competence. PhD Dissertation. Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
Johns R, Sonenshine DE, Hynes WL (1998) Control of bacterial infections in the hard tick Dermacentor variabilis (Acari: Ixodidae): evidence for the existence of antimicrobial proteins in tick hemolymph. J Med Entomol 35:458–464
Johns R, Ohnishi J, Broadwater A, Sonenshine DE, De Silva AM, Hynes WL (2001a) Contrasts in tick innate immune responses to Borrelia burgdorferi challenge: immunotolerance in Ixodes scapularis versus immunocompetence in Dermacentor variabilis (Acari: Ixodidae). J Med Entomol 38:99–107
Johns R, Sonenshine DE, Hynes WL (2001b) Identification of a defensin from the hemolymph of the American dog tick, Dermacentor variabilis. Insect Biochem Mol Biol 31:857–865
Karim S, Kenny B, Troiano E, Mather TN (2008) RNAi-mediated gene silencing in tick synganglia: a proof of concept study. BMC Biotechnol 8:30
Kocan KM, de la Fuente J, Manzano-Roman R, Naranjo V, Sonenshine DE, Hynes WL (2008) Silencing expression of the defensin, varisin, in male Dermacentor variabilis by RNA interference results in reduced Anaplasma marginale infections. Exp Appl Acarol. doi:10.1007/s10493-008-9159-5
Michaut L, Fehlbaum P, Moniatte M, Van Dorsselaer A, Reichhart JM, Bulet P (1996) Determination of the disulfide array of the first inducible antifungal peptide from insects: drosomycin from Drosophila melanogaster. FEBS Lett 395:6–10
Nakajima Y, van der Goes van Naters-Yasui A, Taylor D, Yamakawa M (2001) Two isoforms of a member of the arthropod defensin family from the soft tick, Ornithodoros moubata (Acari: Argasidae). Insect Biochem Mol Biol 31:747–751
Nakajima Y, van der Goes van Naters-Yasui A, Taylor D, Yamakawa M (2002) Antibacterial peptide defensin is involved in midgut immunity of the soft tick, Ornithodoros moubata. Insect Mol Biol 11: 611–618
Oliver JHJ, Wilkenson PR, Kohls GM (1974) Observations on hybridization on three species of North American Dermacentor ticks. J Parasitol 58:375–380
Rudenko N, Golovchenko M, Grubhoffer L (2007) Gene organization of a novel defensin of Ixodes ricinus: first annotation of an intron/exon structure in a hard tick defensin gene and first evidence of the occurrence of two isoforms of one member of the arthropod defensin family. Insect Mol Biol 16:501–507
Schmid-Hempel P (2005) Evolutionary ecology of insect immune defenses. Annu Rev Entomol 50:529–551
Simser JA, Macaluso KR, Mulenga A, Azad AF (2004) Immune-responsive lysozymes from hemocytes of the American dog tick, Dermacentor variabilis and an embryonic cell line of the Rocky Mountain wood tick, D. andersoni. Insect Biochem Mol Biol 34:1235–1246
Sonenshine DE, Hynes WL (2008) Molecular characterization and related aspects of the innate immune response in ticks. Front Biosci 13:7046–7063
Sonenshine DE, Hynes WL, Ceraul SM, Mitchell R, Benzine T (2005) Host blood proteins and peptides in the midgut of the tick Dermacentor variabilis contribute to bacterial control. Exp Appl Acarol 36:207–223
Taylor D (2006) Innate immunity in ticks: a review. J Acarol Soc Jpn 15:109–127
Todd SM, Sonenshine DE, Hynes WL (2007) Tissue and life-stage distribution of a defensin gene in the Lone Star tick, Amblyomma americanum. Med Vet Entomol 21:141–147
Tsuji N, Battsetseg B, Boldbaatar D, Miyoshi T, Xuan X, Oliver JH Jr, Fujisaki K (2007) Babesial vector tick defensin against Babesia sp. parasites. Infect Immun 75:3633–3640
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2008 Springer Science+Business Media B.V.
About this chapter
Cite this chapter
Hynes, W.L., Stokes, M.M., Hensley, S.M., Todd, S.M., Sonenshine, D.E. (2008). Using RNA interference to determine the role of varisin in the innate immune system of the hard tick Dermacentor variabilis (Acari: Ixodidae). In: Bruin, J., van der Geest, L.P.S. (eds) Diseases of Mites and Ticks. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-9695-2_3
Download citation
DOI: https://doi.org/10.1007/978-1-4020-9695-2_3
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-9694-5
Online ISBN: 978-1-4020-9695-2
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)