Project description:Transcriptional profiling of midgut tissues isolated from Rhipicephalus microplus and Rhipicephalus decoloratus females at day 20 post infestation. This enabled the identification of transcripts that are species-specific or shared between the two tick species tested.
Project description:Ixodes species ticks are competent vectors of tick-borne viruses including tick-borne encephalitis and Powassan encephalitis. Tick saliva has been shown to facilitate and enhance viral infection. This likely occurs by saliva-mediated modulation of host responses into patterns favorable for viral infection and dissemination. Because of the rapid kinetics of tick-borne viral transmission, this modulation must occur as early as tick attachment and initiation of feeding. In this study, the gene expression profile of cutaneous bite-site lesions created by uninfected ticks were analyzed at 1, 3, 6, and 12 hours after Ixodes scapularis nymphal tick attachment to discover host pathways or responses potentially important in tick-borne viral establishment.
Project description:Endosymbiotic bacteria associated with eukaryotic hosts are omnipresent in nature, particularly in insects. Studying the bacterial side of host-symbiont interactions is, however, often limited by the unculturability and genetic intractability of the symbionts. Spiroplasma poulsonii is a maternally transmitted bacterial endosymbiont that is naturally associated with several Drosophila species. S. poulsonii strongly affects its host’s physiology, for example by causing male killing or by protecting it against various parasites. Despite intense work on this model since the 1950s, attempts to cultivate endosymbiotic Spiroplasma in vitro have failed so far. Here, we developed a method to sustain the in vitro culture of S. poulsonii by optimizing a commercially accessible medium. We also provide a complete genome assembly, including the first sequence of a natural plasmid of an endosymbiotic Spiroplasma species. Last, by comparing the transcriptome of the in vitro culture to the transcriptome of bacteria extracted from the host, we identified genes putatively involved in host-symbiont interactions. This work provides new opportunities to study the physiology of endosymbiotic Spiroplasma and paves the way to dissect insect-endosymbiont interactions with two genetically tractable partners.
Project description:Transcriptional profiling of midgut tissues isolated from Rhipicephalus microplus and Rhipicephalus decoloratus females at day 20 post infestation. This enabled the identification of transcripts that are species-specific or shared between the two tick species tested. A direct comparison (Balanced block) was performed: Midgut tissues collected on day 20 (post infestation) from R. microplus was compared to that of R. decoloratus. Biological replicates: 3 ; Technical replicates: 1.
Project description:Anaplasma phagocytophilum is an emerging zoonotic pathogen that causes human granulocytic anaplasmosis. These intracellular bacteria establish infection by affecting cell function in both the vertebrate host and the tick vector, Ixodes scapularis. Previous studies have characterized the tick transcriptome and proteome in response to A. phagocytophilum infection. However, in the post-genomic era, the integration of omics datasets through a systems biology approach allows network-based analyses to describe the complexity and functionality of biological systems such as host-pathogen interactions and the discovery of new targets for prevention and control of infectious diseases. This study reports for the first time a systems biology integration of metabolomics, transcriptomics and proteomics data to characterize essential metabolic pathways involved in the response of tick cells to A. phagocytophilum infection. The results showed that infection affected protein processing in endoplasmic reticulum and glucose metabolic pathways in tick cells. These results supported tick-Anaplasma co-evolution by providing new evidence of how tick cells limit pathogen infection, while the pathogen benefits from the tick cell response to establish infection. The results suggested that A. phagocytophilum induces protein misfolding to limit the tick cell response and facilitate infection, but requires protein degradation to prevent ER stress and cell apoptosis to survive in infected cells. Additionally, A. phagocytophilum may benefit from the tick cellâs ability to limit bacterial infection through PEPCK inhibition leading to decreased glucose metabolism, which also results in the inhibition of cell apoptosis that increases infection of tick cells. These results support the use of this experimental approach to systematically identify tick cell pathways and molecular mechanisms involved in tick-pathogen interactions Two samples with two replicates each were analyzed. Samples included Ixodes scapularis ISE6 cells uninfected (control) and infected with Anaplasma phagocytophilum human NY18 isolate.
Project description:Ixodes species ticks are competent vectors of tick-borne viruses including tick-borne encephalitis and Powassan encephalitis. Tick saliva has been shown to facilitate and enhance viral infection. This likely occurs by saliva-mediated modulation of host responses into patterns favorable for viral infection and dissemination. Because of the rapid kinetics of tick-borne viral transmission, this modulation must occur as early as tick attachment and initiation of feeding. In this study, the gene expression profile of cutaneous bite-site lesions created by uninfected ticks were analyzed at 1, 3, 6, and 12 hours after Ixodes scapularis nymphal tick attachment to discover host pathways or responses potentially important in tick-borne viral establishment. Four milimeter ear biopsies from BALB/cJ mice infested with Ixodes scapularis nymphs were assayed using Affymetrix genechip 430A 2.0 arrays at 1, 3, 6, and 12 hours after infestation during a primary exposure. 3 mice were measured at each time point. Controls were 3 similarly housed but tick-free mice.
Project description:There has been an emergence and expansion of tick-borne diseases in Europe, Asia and North America in recent years, including Lyme disease, tick-borne encephalitis, and human anaplasmosis. The primary tick vectors implicated are hard ticks of the Ixodes genera. Although much is known about the host response to these bacterial and viral pathogens, there is limited knowledge of the cellular responses to infection within the tick vector. The bacterium Anaplasma phagocytophilum (A. phagocytophilum), is able to bypass apoptotic processes in ticks, enabling infection to proceed. However, the tick cellular responses to infection with the flaviviruses tick-borne encephalitis virus (TBEV) and louping ill virus (LIV), which cause tick-borne encephalitis and louping ill respectively, are less clear. Infection of an Ixodes ricinus (I. ricinus) tick cell line with the viruses LIV and TBEV, and the bacterium A. phagocytophilum, identified activation of common and distinct cellular pathways. In particular, commonly-upregulated genes included those that modulate apoptotic pathways (HSP70), putative anti-pathogen genes (FKBP and XBL1), and genes that influence the tick innate immune response, including selective activation of toll genes. These data provide an insight into potentially key genes involved in the tick cellular response to viral or bacterial infection.
Project description:Arabidopsis thaliana plants were infested i) with sucking insect herbivores (the generalist aphid Myzus persicae and the specialist aphid Brevicoryne brassicae), ii) with chewing insect herbivores (generalist caterpillars of Spodoptera exigua and specialist caterpillars of Pieris rapae) or iii) were treated by wounding. For each treatment, rosette leaves were harvested at two time points (6h and 24h) after removal of insects. For chewing herbivores and wounding both local, i.e. immediately damaged leaves, and systemic, i.e. undamaged leaves from the same plant, were collected. Control plants were uninfested, but otherwise equally treated and harvested in parallel. We tested the hypothesis that Arabidopsis can recognize and respond differentially to insect species at the transcriptional level using a genome wide microarray. Transcriptional reprogramming was characterized using co-expression analysis in damaged and undamaged leaves at two times in response to mechanical wounding and four insect species. In all, 2778 (10.6%) of annotated genes on the array were differentially expressed in at least one treatment. Responses differed mainly between aphid and caterpillar and sampling times. Responses to aphids and caterpillars shared only 10% of up-regulated and 8% of down-regulated genes. Responses to two caterpillars shared 21% and 12% of up- and down-regulated genes, whereas responses to the two aphids shared only 7% and 4% of up-regulated and down-regulated genes. Overlap in genes expressed between 6h and 24h was 3-15%, and depended on the insect species. Responses in attacked and unattacked leaves differed at 6h but converged by 24h. Genes responding to the insects are also responsive to many stressors and included primary metabolism. Aphids down-regulated amino acid catabolism; caterpillars stimulated production of amino acids involved in glucosinolate synthesis. Co-expression analysis revealed 17 response networks. Transcription factors were a major portion of differentially expressed genes throughout and responsive genes shared most of the known or postulated binding sites.