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Daniel E. Sonenshine - One of the best experts on this subject based on the ideXlab platform.

  • tick ecdysteroid hormone global microbiota rickettsia signaling in the ovary versus carcass during vitellogenesis in part fed virgin american dog ticks Dermacentor Variabilis
    Microorganisms, 2021
    Co-Authors: Loganathan Ponnusamy, Daniel E. Sonenshine, Charles S. Apperson, Haley Sutton, Robert D Mitchell, R M Roe
    Abstract:

    The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor Variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed.

  • Tick Ecdysteroid Hormone, Global Microbiota/Rickettsia Signaling in the Ovary versus Carcass during Vitellogenesis in Part-Fed (Virgin) American Dog Ticks, Dermacentor Variabilis
    'MDPI AG', 2021
    Co-Authors: Loganathan Ponnusamy, Daniel E. Sonenshine, Charles S. Apperson, Haley Sutton, Robert D Mitchell, Richard Michael Roe
    Abstract:

    The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor Variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed

  • infrared light detection by the haller s organ of adult american dog ticks Dermacentor Variabilis ixodida ixodidae
    Ticks and Tick-borne Diseases, 2017
    Co-Authors: Robert D Mitchell, Jiwei Zhu, Daniel E. Sonenshine, Ann L Carr, Anirudh Dhammi, Grayson Cave, Michael R Roe
    Abstract:

    Abstract The Haller’s organ (HO), unique to ticks and mites, is found only on the first tarsus of the front pair of legs. The organ has an unusual morphology consisting of an anterior pit (AP) with protruding sensilla and a posterior capsule (Cp). The current thinking is that the HO’s main function is chemosensation analogous to the insect antennae, but the functionality of its atypical structure (exclusive to the Acari) is unexplained. We provide the first evidence that the HO allows the American dog tick, Dermacentor Variabilis , to respond to infrared (IR) light. Unfed D. Variabilis adults with their HOs present were positively phototactic to IR. However, when the HOs were removed, no IR response was detected. Ticks in these experiments were also attracted to white light with and without the HOs, but were only positively phototactic to white light when the ocelli (primitive eyes) were unobstructed. Covering the eyes did not prevent IR attraction. A putative TRPA1 receptor was characterized from a D. Variabilis -specific HO transcriptome we constructed. This receptor was homologous to transient receptor potential cation channel, subfamily A, member 1 (TRPA1) from the pit organ of the pit viper, python, and boa families of snakes, the only receptor identified so far for IR detection. HO scanning electron microscopy (SEM) studies in the American dog tick showed the AP and Cp but also novel structures not previously described; the potential role of these structures in IR detection is discussed. The ability of ticks to use IR for host finding is consistent with their obligatory hematophagy and has practical applications in tick trapping and the development of new repellents.

  • gene expression of tissue specific molecules in ex vivo Dermacentor Variabilis acari ixodidae during rickettsial exposure
    Journal of Medical Entomology, 2013
    Co-Authors: Natthida Petchampai, Piyanate Sunyakumthorn, Michael T Kearney, Daniel E. Sonenshine, Britton J Grasperge, Kevin R Macaluso
    Abstract:

    ABSTRACT Ticks serve as both vectors and the reservoir hosts capable of transmitting spotted fever group Rickettsia by horizontal and vertical transmission. Persistent maintenance of Rickettsia species in tick populations is dependent on the specificity of the tick and Rickettsia relationship that limits vertical transmission of particular Rickettsia species, suggesting host-derived mechanisms of control. Tick-derived molecules are differentially expressed in a tissue-specific manner in response to rickettsial infection; however, little is known about tick response to specific rickettsial species. To test the hypothesis that tissue-specific tick-derived molecules are uniquely responsive to rickettsial infection, a bioassay to characterize the tick tissue-specific response to different rickettsial species was used. Whole organs of Dermacentor Variabilis (Say) were exposed to either Rickettsia montanensis or Rickettsia amblyommii, two Rickettsia species common, or absent, in field-collected D. Variabilis, r...

  • molecular characterization and tissue specific gene expression of Dermacentor Variabilis α catenin in response to rickettsial infection
    Insect Molecular Biology, 2012
    Co-Authors: Piyanate Sunyakumthorn, Natthida Petchampai, Michael T Kearney, Daniel E. Sonenshine, Kevin R Macaluso
    Abstract:

    Alpha catenin is a cytoskeleton protein that acts as a regulator of actin rearrangement by forming an E-cadherin adhesion complex. In Dermacentor Variabilis, a putative α-catenin (Dvα-catenin) was previously identified as differentially regulated in ovaries of ticks chronically infected with Rickettsia montanensis. To begin characterizing the role(s) of Dvα-catenin during rickettsial infection, the full-length Dvα-catenin cDNA was cloned and analysed. Comparative sequence analysis demonstrates a 3069-bp cDNA with a 2718-bp open reading frame with a sequence similar to Ixodes scapularisα-catenin. A portion of Dvα-catenin is homologous to the vinculin-conserved domain containing a putative actin-binding region and β-catenin-binding and -dimerization regions. Quantitative reverse-transcription PCR analysis demonstrated that Dvα-catenin is predominantly expressed in tick ovaries and is responsive to tick feeding. The tissue-specific gene expression analysis of ticks exposed to Rickettsia demonstrates that Dvα-catenin expression was significantly downregulated 12 h after exposure to R. montanensis, but not in Rickettsia amblyommii-exposed ovaries, compared with Rickettsia-unexposed ticks. Studying tick-derived molecules associated with rickettsial infection will provide a better understanding of the transmission dynamics of tick-borne rickettsial diseases.

Abdu F. Azad - One of the best experts on this subject based on the ideXlab platform.

  • Comparative vertical transmission of Rickettsia by Dermacentor Variabilis and Amblyomma maculatum.
    Ticks and tick-borne diseases, 2017
    Co-Authors: Emma K. Harris, Victoria I Verhoeve, Kaikhushroo H Banajee, Jacqueline A. Macaluso, Abdu F. Azad
    Abstract:

    The geographical overlap of multiple Rickettsia and tick species coincides with the molecular detection of a variety of rickettsial agents in what may be novel tick hosts. However, little is known concerning transmissibility of rickettsial species by various tick hosts. To examine the vertical transmission potential between select tick and rickettsial species, two sympatric species of ticks, Dermacentor Variabilis and Amblyomma maculatum, were exposed to five different rickettsial species, including Rickettsia rickettsii, Rickettsia parkeri, Rickettsia montanensis, Rickettsia amblyommatis, or flea-borne Rickettsia felis. Fitness-related metrics including engorgement weight, egg production index, nutrient index, and egg hatch percentage were then assessed. Subsamples of egg clutches and unfed larvae, nymphs, and adults for each cohort were assessed for transovarial and transstadial transmission of rickettsiae by qPCR. Rickettsial exposure had a minimal fitness effect in D. Variabilis and transovarial transmission was observed for all groups except R. rickettsii. In contrast, rickettsial exposure negatively influenced A. maculatum fitness and transovarial transmission of rickettsiae was demonstrated only for R. amblyommatis- and R. parkeri-exposed ticks. Sustained maintenance of rickettsiae via transstadial transmission was diminished from F1 larvae to F1 adults in both tick species. The findings of this study suggest transovarial transmission specificity may not be tick species dependent, and sustained vertical transmission is not common.

  • molecular and functional characterization of vacuolar atpase from the american dog tick Dermacentor Variabilis
    Insect Molecular Biology, 2014
    Co-Authors: Natthida Petchampai, Piyanate Sunyakumthorn, Michael T Kearney, Mark L. Guillotte, Abdu F. Azad, Albert Mulenga, Chutima Thepparit, Kevin R Macaluso
    Abstract:

    Vacuolar (V)-ATPase is a proton-translocating enzyme that acidifies cellular compartments for various functions such as receptor-mediated endocytosis, intracellular trafficking and protein degradation. Previous studies in Dermacentor Variabilis chronically infected with Rickettsia montanensis have identified V-ATPase as one of the tick-derived molecules transcribed in response to rickettsial infection. To examine the role of the tick V-ATPase in tick–Rickettsia interactions, a full-length 2887-bp cDNA (2532-bp open reading frame) clone corresponding to the transcript of the V0 domain subunit a of D. Variabilis V-ATPase (DvVATPaseV0a) gene encoding an 843 amino acid protein with an estimated molecular weight of ∼96 kDa was isolated from D. Variabilis. Amino acid sequence analysis of DvVATPaseV0a showed the highest similarity to VATPaseV0a from Ixodes scapularis. A potential N-glycosylation site and eight putative transmembrane segments were identified in the sequence. Western blot analysis of tick tissues probed with polyclonal antibody raised against recombinant DvVATPaseV0a revealed the expression of V-ATPase in the tick ovary. Transcriptional profiles of DvVATPaseV0a demonstrated a greater mRNA expression in the tick ovary, compared with the midgut and salivary glands; however, the mRNA level in each of these tick tissues remained unchanged after infection with R. montanensis for 1 h. V-ATPase inhibition bioassays resulted in a significant decrease in the ability of R. montanensis to invade tick cells in vitro, suggesting a role of V-ATPase in rickettsial infection of tick cells. Characterization of tick-derived molecules involved in rickettsial infection is essential for a thorough understanding of rickettsial transmission within tick populations and the ecology of tick-borne rickettsial diseases.

  • a kunitz protease inhibitor from Dermacentor Variabilis a vector for spotted fever group rickettsiae limits rickettsia montanensis invasion
    Infection and Immunity, 2011
    Co-Authors: Shane M Ceraul, Vsevolod L. Popov, Sayeedur M. Rahman, Ashley Chung, Khandra T Sears, Magda Beiersexton, Abdu F. Azad
    Abstract:

    A defining facet of tick-Rickettsia symbioses is the molecular strategy employed by each partner to ensure its own survival. Ticks must control rickettsial colonization to avoid immediate death. In the current study, we show that rickettsial abundance in the tick midgut increases once the expression of a Kunitz-type serine protease inhibitor from the American dog tick (Dermacentor Variabilis) (DvKPI) is suppressed by small interfering RNA (siRNA). A series of in vitro invasion assays suggested that DvKPI limits rickettsial colonization during host cell entry. Interestingly, we observed that DvKPI associates with rickettsiae in vitro as well as in the tick midgut. Collectively, our data demonstrate that DvKPI limits host cell invasion by Rickettsia montanensis, possibly through an association with the bacterium.

  • functional characterization and novel rickettsiostatic effects of a kunitz type serine protease inhibitor from the tick Dermacentor Variabilis
    Infection and Immunity, 2008
    Co-Authors: Shane M Ceraul, Sayeedur M. Rahman, Albert Mulenga, Sheila M Dreherlesnick, Abdu F. Azad
    Abstract:

    Here we report the novel bacteriostatic function of a five-domain Kunitz-type serine protease inhibitor (KPI) from the tick Dermacentor Variabilis. As ticks feed, they release anticoagulants, anti-inflammatory and immunosuppressive molecules that mediate the formation of the feeding lesion on the mammalian host. A number of KPIs have been isolated and characterized from tick salivary gland extracts. Interestingly, we observe little D. Variabilis KPI gene expression in the salivary gland and abundant expression in the midgut. However, our demonstration of D. Variabilis KPI's anticoagulant properties indicates that D. Variabilis KPI may be important for blood meal digestion in the midgut. In addition to facilitating long-term attachment and blood meal acquisition, gene expression studies of Drosophila, legumes, and ticks suggest that KPIs play some role in the response to microbial infection. Similarly, in this study, we show that challenge of D. Variabilis with the spotted fever group rickettsia, Rickettsia montanensis, results in sustained D. Variabilis KPI gene expression in the midgut. Furthermore, our in vitro studies show that D. Variabilis KPI limits rickettsial colonization of L929 cells (mouse fibroblasts), implicating D. Variabilis KPI as a bacteriostatic protein, a property that may be related to D. Variabilis KPI's trypsin inhibitory capability. This work suggests that anticoagulants play some role in the midgut during feeding and that D. Variabilis KPI may be involved as part of the tick's defense response to rickettsiae.

  • differential expression of two glutathione s transferases identified from the american dog tick Dermacentor Variabilis
    Insect Molecular Biology, 2006
    Co-Authors: Sheila M Dreherlesnick, Jason A Simser, Albert Mulenga, Abdu F. Azad
    Abstract:

    Reciprocal signalling and gene expression play a cardinal role during pathogen-host molecular interactions and are prerequisite to the maintenance of balanced homeostasis. Gene expression repertoire changes during rickettsial infection and glutathione-S-transferases (GSTs) were among the genes found up-regulated in Rickettsia-infected Dermacentor Variabilis. GSTs are well known to play an important part in cellular stress responses in the host. We have cloned two full-length GSTs from D. Variabilis (DvGST1 and DvGST2). Comparison of these two DvGST molecules with those of other species indicate that DvGST1 is related to the mammalian class theta and insect class delta GSTs, while DvGST2 does not seem to fall in the same family. Northern blotting analyses revealed differential expression patterns, where DvGST1 and DvGST2 transcripts are found in the tick gut, with DvGST2 transcripts also present in the ovaries. Both DvGST transcripts are up-regulated upon tick feeding. Challenge of fed adult ticks with Escherichia coli injection showed decreased transcript amounts compared with ticks injected with phosphate-buffered saline (sham) and naive ticks.

Shane M Ceraul - One of the best experts on this subject based on the ideXlab platform.

  • defending the fort a role for defensin 2 in limiting rickettsia montanensis infection of Dermacentor Variabilis
    Insect Molecular Biology, 2014
    Co-Authors: Rebecca S Pelc, Khandra T Sears, Jennifer Mcclure, A Chung, M S Rahman, Shane M Ceraul
    Abstract:

    The importance of tick defensins is evidenced by their expression in a wide variety of tick tissues and prevalence across many tick genera. To date, the functional and biological significance of defensin-2 as a rickettsiastatic or rickettsiacidal antimicrobial peptide has not been addressed. In a previous study, defensin-2 transcription was shown to increase in Dermacentor Variabilis ticks challenged with Rickettsia montanensis. In the present study, the hypothesis that defensin-2 is functional as a rickettsiastatic and/or rickettsiacidal antimicrobial peptide is tested. We show that defensin-2 plays a role in reducing burden after acquisition of Rickettsia montanensis through capillary feeding. Moreover, defensin-2 is shown to associate with R. montanensis in vitro and in vivo, causing cytoplasmic leakiness.

  • a kunitz protease inhibitor from Dermacentor Variabilis a vector for spotted fever group rickettsiae limits rickettsia montanensis invasion
    Infection and Immunity, 2011
    Co-Authors: Shane M Ceraul, Vsevolod L. Popov, Sayeedur M. Rahman, Ashley Chung, Khandra T Sears, Magda Beiersexton, Abdu F. Azad
    Abstract:

    A defining facet of tick-Rickettsia symbioses is the molecular strategy employed by each partner to ensure its own survival. Ticks must control rickettsial colonization to avoid immediate death. In the current study, we show that rickettsial abundance in the tick midgut increases once the expression of a Kunitz-type serine protease inhibitor from the American dog tick (Dermacentor Variabilis) (DvKPI) is suppressed by small interfering RNA (siRNA). A series of in vitro invasion assays suggested that DvKPI limits rickettsial colonization during host cell entry. Interestingly, we observed that DvKPI associates with rickettsiae in vitro as well as in the tick midgut. Collectively, our data demonstrate that DvKPI limits host cell invasion by Rickettsia montanensis, possibly through an association with the bacterium.

  • functional characterization and novel rickettsiostatic effects of a kunitz type serine protease inhibitor from the tick Dermacentor Variabilis
    Infection and Immunity, 2008
    Co-Authors: Shane M Ceraul, Sayeedur M. Rahman, Albert Mulenga, Sheila M Dreherlesnick, Abdu F. Azad
    Abstract:

    Here we report the novel bacteriostatic function of a five-domain Kunitz-type serine protease inhibitor (KPI) from the tick Dermacentor Variabilis. As ticks feed, they release anticoagulants, anti-inflammatory and immunosuppressive molecules that mediate the formation of the feeding lesion on the mammalian host. A number of KPIs have been isolated and characterized from tick salivary gland extracts. Interestingly, we observe little D. Variabilis KPI gene expression in the salivary gland and abundant expression in the midgut. However, our demonstration of D. Variabilis KPI's anticoagulant properties indicates that D. Variabilis KPI may be important for blood meal digestion in the midgut. In addition to facilitating long-term attachment and blood meal acquisition, gene expression studies of Drosophila, legumes, and ticks suggest that KPIs play some role in the response to microbial infection. Similarly, in this study, we show that challenge of D. Variabilis with the spotted fever group rickettsia, Rickettsia montanensis, results in sustained D. Variabilis KPI gene expression in the midgut. Furthermore, our in vitro studies show that D. Variabilis KPI limits rickettsial colonization of L929 cells (mouse fibroblasts), implicating D. Variabilis KPI as a bacteriostatic protein, a property that may be related to D. Variabilis KPI's trypsin inhibitory capability. This work suggests that anticoagulants play some role in the midgut during feeding and that D. Variabilis KPI may be involved as part of the tick's defense response to rickettsiae.

  • capillary tube feeding system for studying tick pathogen interactions of Dermacentor Variabilis acari ixodidae and anaplasma marginale rickettsiales anaplasmataceae
    Journal of Medical Entomology, 2005
    Co-Authors: Katherine M. Kocan, Jose De La Fuente, Shane M Ceraul, Daniel E. Sonenshine, Edmour F. Blouin, Joy H Yoshioka, Consuelo Almazan
    Abstract:

    Abstract A capillary tube feeding (CTF) system was adapted for studying the interaction between Dermacentor Variabilis (Say) and the rickettsial cattle pathogen Anaplasma marginale Theiler. A. marginale undergoes a complex developmental cycle in ticks that begins in midguts and ends by transmission from salivary glands. In this CTF system, male D. Variabilis were fed A. marginale-infected blood or cultured tick cells. Ticks that fed on highly rickettsemic calves developed midgut and salivary gland infections as detected by PCR, whereas ticks that were fed from capillary tubes on the same blood developed only midgut infections. An unexpected result of capillary tube feeding was that antibodies against the A. marginale adhesin, major surface protein 1a, enhanced midgut infections and caused cell culture-derived A. marginale to infect midguts. Another unexpected result was the infection of the midguts of the nonvector tick Amblyomma americanum (L.), after capillary tube feeding on infected bovine blood. The ...

  • an arthropod defensin expressed by the hemocytes of the american dog tick Dermacentor Variabilis acari ixodidae
    Insect Biochemistry and Molecular Biology, 2003
    Co-Authors: Shane M Ceraul, Daniel E. Sonenshine, Robert E Ratzlaff, Wayne L. Hynes
    Abstract:

    Both soluble and cell-mediated components are involved in the innate immune response of arthropods. Injection of Borrelia burgdorferi, the Lyme disease agent, results in the secretion of defensin into the hemolymph of the ixodid tick, Dermacentor Variabilis. The presence of the peptide is observed as early as 15 min post-challenge and remains present through 18 h post-challenge. As observed in insects and soft ticks, the transcript for defensin is detected as early as 1 h post-challenge in D. Variabilis. RT-PCR resulted in an amplicon of 624 bp with a 225 bp region that translates to a 74 amino acid preprodefensin. The defensin encoding region was amplified, cloned and sequenced from the hemocytes. It appears as though defensin is stored in the granulocytes of the hemolymph and secreted into the hemolymph upon bacterial insult. The role of defensin as a contributing factor in determining vector competency is discussed.

Wayne L. Hynes - One of the best experts on this subject based on the ideXlab platform.

  • Prevalence of Ehrlichia chaffeensis and Ehrlichia ewingii in Amblyomma americanum and Dermacentor Variabilis collected from southeastern Virginia, 2010-2011.
    Ticks and tick-borne diseases, 2014
    Co-Authors: Chelsea L. Wright, Holly Gaff, Wayne L. Hynes
    Abstract:

    Amblyomma americanum is the most commonly encountered tick species in southeastern Virginia, representing approximately 95% of the human-biting tick population in this area. Here we investigated the prevalence of Ehrlichia chaffeensis and Ehrlichia ewingii in questing Amblyomma americanum and Dermacentor Variabilis ticks collected from multiple sites in southeastern Virginia from 2010 to 2011. Although both Ehrlichia species were detected in Amblyomma americanum, no evidence of either pathogen was found in Dermacentor Variabilis. Prevalence of E. chaffeensis varied by location, ranging from 0 to 5.08% among Amblyomma americanum populations. Ehrlichia ewingii prevalence was slightly higher, ranging from 0 to 8.20% among A. americanum populations. We conclude that both pathogens are established in southeastern Virginia A. americanum populations, and that although there are no apparent temporal trends in Ehrlichia prevalence, there is variation among locations, suggesting the potential for disease hotspots.

  • an arthropod defensin expressed by the hemocytes of the american dog tick Dermacentor Variabilis acari ixodidae
    Insect Biochemistry and Molecular Biology, 2003
    Co-Authors: Shane M Ceraul, Daniel E. Sonenshine, Robert E Ratzlaff, Wayne L. Hynes
    Abstract:

    Both soluble and cell-mediated components are involved in the innate immune response of arthropods. Injection of Borrelia burgdorferi, the Lyme disease agent, results in the secretion of defensin into the hemolymph of the ixodid tick, Dermacentor Variabilis. The presence of the peptide is observed as early as 15 min post-challenge and remains present through 18 h post-challenge. As observed in insects and soft ticks, the transcript for defensin is detected as early as 1 h post-challenge in D. Variabilis. RT-PCR resulted in an amplicon of 624 bp with a 225 bp region that translates to a 74 amino acid preprodefensin. The defensin encoding region was amplified, cloned and sequenced from the hemocytes. It appears as though defensin is stored in the granulocytes of the hemolymph and secreted into the hemolymph upon bacterial insult. The role of defensin as a contributing factor in determining vector competency is discussed.

  • identification of a defensin from the hemolymph of the american dog tick Dermacentor Variabilis
    Insect Biochemistry and Molecular Biology, 2001
    Co-Authors: Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes
    Abstract:

    Hemolymph from partially fed virgin Dermacentor Variabilis females was collected following Borrelia burgdorferi challenge and assayed for antimicrobial activity against Bacillus subtilis and B. burgdorferi. A small inducible cationic peptide was identified by SDS-PAGE in the hemolymph of these ticks as early as 1h post challenge. Following purification by a three-step procedure involving sequential SepPak elution, reversed phase high performance liquid chromatography (RP-HPLC) and gel electrophoresis, the yield of the active peptide was approximately 0.1% of the total protein in the hemolymph plasma. The molecular weight, 4.2kDa, was determined by MALDI-TOF mass spectrometry. N-terminal sequencing by the Edman degradation method gave a sequence for the first 30 amino acids as: G-F-G-C-P-L-N-Q-G-A-C-H-N-H-C-R-S-I-(R)-(R)-(R)-G-G-Y-C-S-Q-I-I-K. A computer search of databases showed that the peptide had 83% similarity to a defensin found in a scorpion. This is the first report of a defensin from a tick. The peptide was stable at least up to 70 degrees C. Although the tick defensin alone was not immediately effective against B. burgdorferi, tick defensin plus lysozyme killed more than 65% of cultured B. burgdorferi within 1h.

  • identification of a defensin from the hemolymph of the american dog tick Dermacentor Variabilis
    Insect Biochemistry and Molecular Biology, 2001
    Co-Authors: Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes
    Abstract:

    Hemolymph from partially fed virgin Dermacentor Variabilis females was collected following Borrelia burgdorferi challenge and assayed for antimicrobial activity against Bacillus subtilis and B. burgdorferi. A small inducible cationic peptide was identified by SDS-PAGE in the hemolymph of these ticks as early as 1 h post challenge. Following purification by a three-step procedure involving sequential SepPak elution, reversed phase high performance liquid chromatography (RP-HPLC) and gel electrophoresis, the yield of the active peptide was approximately 0.1% of the total protein in the hemolymph plasma. The molecular weight, 4.2 kDa, was determined by MALDI-TOF mass spectrometry. N-terminal sequencing by the Edman degradation method gave a sequence for the first 30 amino acids as: G-F-G-C-P-L-N-Q-G-A-C-H-N-H-C-R-S-I-(R)-(R)-(R)-G-G-Y-C-S-Q-I-I-K. A computer search of databases showed that the peptide had 83% similarity to a defensin found in a scorpion. This is the first report of a defensin from a tick. The peptide was stable at least up to 70°C. Although the tick defensin alone was not immediately effective against B. burgdorferi, tick defensin plus lysozyme killed more than 65% of cultured B. burgdorferi within 1 h.  2001 Elsevier Science Ltd. All rights reserved.

  • response of the tick Dermacentor Variabilis acari ixodidae to hemocoelic inoculation of borrelia burgdorferi spirochetales
    Journal of Medical Entomology, 2000
    Co-Authors: Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes
    Abstract:

    When Borrelia burgdorferi B31 low passage strain spirochetes were directly injected into the hemocoel of Dermacentor Variabilis (Say) females, the bacteria were cleared from the hemocoel within < 24 h. Viable spirochetes were not found in hemolymph, salivary gland, or ovary tissues by subculturing or by IFA. The hemocyte population increased approximately 6 times within the first 6 h after inoculation compared with the uninoculated controls. In contrast, the soluble total hemolymph protein content decreased inversely with the increase in hemocytes. Borreliacidal activity was demonstrated with cell-free hemolymph from D. Variabilis. In vitro antimicrobial assays using hemolymph from borrelia-challenged and nonchallenged ticks resulted in 72% spirochete reductions compared with only 11.5%, respectively, within 1 h. Additional evidence of induced antimicrobial hemolymph protein activity was demonstrated by SDS-PAGE, which revealed upregulation of a lysozyme-like peptide (approximately 15 kDa) (22% increase) and the induction of a approximately 5.8 kDa peptide in the B. burgdorferi-challenged ticks. In contrast with the nonvector borne Bacillus subtilis, D. Variabilis presented a rapid and robust response to challenge with cultured B. burgdorferi spirochetes and lead to their early elimination. The role of the tick immune system, including possible differences between vector and nonvector ticks, in determining the success of invasive bacteria is discussed.

Kevin R Macaluso - One of the best experts on this subject based on the ideXlab platform.

  • molecular and functional characterization of vacuolar atpase from the american dog tick Dermacentor Variabilis
    Insect Molecular Biology, 2014
    Co-Authors: Natthida Petchampai, Piyanate Sunyakumthorn, Michael T Kearney, Mark L. Guillotte, Abdu F. Azad, Albert Mulenga, Chutima Thepparit, Kevin R Macaluso
    Abstract:

    Vacuolar (V)-ATPase is a proton-translocating enzyme that acidifies cellular compartments for various functions such as receptor-mediated endocytosis, intracellular trafficking and protein degradation. Previous studies in Dermacentor Variabilis chronically infected with Rickettsia montanensis have identified V-ATPase as one of the tick-derived molecules transcribed in response to rickettsial infection. To examine the role of the tick V-ATPase in tick–Rickettsia interactions, a full-length 2887-bp cDNA (2532-bp open reading frame) clone corresponding to the transcript of the V0 domain subunit a of D. Variabilis V-ATPase (DvVATPaseV0a) gene encoding an 843 amino acid protein with an estimated molecular weight of ∼96 kDa was isolated from D. Variabilis. Amino acid sequence analysis of DvVATPaseV0a showed the highest similarity to VATPaseV0a from Ixodes scapularis. A potential N-glycosylation site and eight putative transmembrane segments were identified in the sequence. Western blot analysis of tick tissues probed with polyclonal antibody raised against recombinant DvVATPaseV0a revealed the expression of V-ATPase in the tick ovary. Transcriptional profiles of DvVATPaseV0a demonstrated a greater mRNA expression in the tick ovary, compared with the midgut and salivary glands; however, the mRNA level in each of these tick tissues remained unchanged after infection with R. montanensis for 1 h. V-ATPase inhibition bioassays resulted in a significant decrease in the ability of R. montanensis to invade tick cells in vitro, suggesting a role of V-ATPase in rickettsial infection of tick cells. Characterization of tick-derived molecules involved in rickettsial infection is essential for a thorough understanding of rickettsial transmission within tick populations and the ecology of tick-borne rickettsial diseases.

  • gene expression of tissue specific molecules in ex vivo Dermacentor Variabilis acari ixodidae during rickettsial exposure
    Journal of Medical Entomology, 2013
    Co-Authors: Natthida Petchampai, Piyanate Sunyakumthorn, Michael T Kearney, Daniel E. Sonenshine, Britton J Grasperge, Kevin R Macaluso
    Abstract:

    ABSTRACT Ticks serve as both vectors and the reservoir hosts capable of transmitting spotted fever group Rickettsia by horizontal and vertical transmission. Persistent maintenance of Rickettsia species in tick populations is dependent on the specificity of the tick and Rickettsia relationship that limits vertical transmission of particular Rickettsia species, suggesting host-derived mechanisms of control. Tick-derived molecules are differentially expressed in a tissue-specific manner in response to rickettsial infection; however, little is known about tick response to specific rickettsial species. To test the hypothesis that tissue-specific tick-derived molecules are uniquely responsive to rickettsial infection, a bioassay to characterize the tick tissue-specific response to different rickettsial species was used. Whole organs of Dermacentor Variabilis (Say) were exposed to either Rickettsia montanensis or Rickettsia amblyommii, two Rickettsia species common, or absent, in field-collected D. Variabilis, r...

  • molecular characterization and tissue specific gene expression of Dermacentor Variabilis α catenin in response to rickettsial infection
    Insect Molecular Biology, 2012
    Co-Authors: Piyanate Sunyakumthorn, Natthida Petchampai, Michael T Kearney, Daniel E. Sonenshine, Kevin R Macaluso
    Abstract:

    Alpha catenin is a cytoskeleton protein that acts as a regulator of actin rearrangement by forming an E-cadherin adhesion complex. In Dermacentor Variabilis, a putative α-catenin (Dvα-catenin) was previously identified as differentially regulated in ovaries of ticks chronically infected with Rickettsia montanensis. To begin characterizing the role(s) of Dvα-catenin during rickettsial infection, the full-length Dvα-catenin cDNA was cloned and analysed. Comparative sequence analysis demonstrates a 3069-bp cDNA with a 2718-bp open reading frame with a sequence similar to Ixodes scapularisα-catenin. A portion of Dvα-catenin is homologous to the vinculin-conserved domain containing a putative actin-binding region and β-catenin-binding and -dimerization regions. Quantitative reverse-transcription PCR analysis demonstrated that Dvα-catenin is predominantly expressed in tick ovaries and is responsive to tick feeding. The tissue-specific gene expression analysis of ticks exposed to Rickettsia demonstrates that Dvα-catenin expression was significantly downregulated 12 h after exposure to R. montanensis, but not in Rickettsia amblyommii-exposed ovaries, compared with Rickettsia-unexposed ticks. Studying tick-derived molecules associated with rickettsial infection will provide a better understanding of the transmission dynamics of tick-borne rickettsial diseases.

  • an immune responsive factor d like serine proteinase homologue identified from the american dog tick Dermacentor Variabilis
    Insect Molecular Biology, 2004
    Co-Authors: Jason A Simser, Albert Mulenga, Kevin R Macaluso, Abdu F. Azad
    Abstract:

    A Dermacentor Variabilis cDNA encoding a clip-domain serine proteinase homologue with glycine replacing the catalytic serine was identified from tick haemocytes. The D. Variabilis product was most similar to Tachypleus tridentatus haemocyte antimicrobial factor D and shared significant homologies with a number of immune-responsive gene products of arthropods, including insect prophenoloxidase-activating cofactors. Northern blotting analyses confirmed that the tick serine proteinase homologue expression levels were highest in haemocytes, and to lesser degrees in ovaries and then salivary glands whereas steady-state levels of expression in whole ticks were found to be slightly higher in fed versus unfed adults or eggs. Challenge of fed adults by Escherichia coli injection demonstrated that transcript abundance was significantly increased above those of naive controls in a temporal fashion. Additionally, an apparent orthologue of the D. Variabilis clip-domain molecule was cloned, and expression detected, from a Dermacentor andersoni cell line indicating cross species conservation.

  • the american dog tick Dermacentor Variabilis encodes a functional histamine release factor homolog
    Insect Biochemistry and Molecular Biology, 2003
    Co-Authors: Albert Mulenga, Kevin R Macaluso, Jason A Simser, Abdu F. Azad
    Abstract:

    We have identified a functional Dermacentor Variabilis histamine release factor (DVHRF) homolog and shown that it is a secreted tick saliva protein. The 945 base pair (bp) full-length DVHRF cDNA has a 522 bp open reading frame that encodes a 20 kDa (173 amino acid) polypeptide. Sequence analysis showed that the two HRF signature amino acid sequences were conserved in DVHRF, indicating close structural similarity between DVHRF and other characterized HRF homologs. Northern and Western blotting analyses of partially fed and unfed ticks indicates that neither DVHRF transcriptional nor translational regulation were influenced by tick feeding activity. Like its counterparts from the mammalian system, tick DVHRF is expressed in various tissues, as assessed by both Northern and Western blotting analyses. Furthermore, an Escherichia coli-expressed recombinant DVHRF induced histamine secretion from a rat basophilic leukemic cell line in a dose-dependent manner. Extensive experimental evidence has shown that high levels of histamine at tick attachment sites impede the biological success of feeding ticks and, in response, ticks secrete histamine-binding proteins to minimize the adverse effects of histamine. Our results suggest the existence of a tick-derived multifaceted control mechanism for levels of histamine at tick feeding sites.