Project description:The midgut of the tick is the most important tissue for the storage and digestion of host blood, which serves as the sole source of energy and nutrients for all tick development and reproduction. During feeding at each developmental stage, dynamic changes in the tick midgut epithelium reflect changes in physiological processes in this tissue. In addition, the midgut serves as the primary interface between the tick and tick-borne pathogens, which determines the vector competence of the tick. Several transcriptome data from Ixodes ricinus have been published, but few studies have examined tick proteomes. In contrast to transcriptome data, proteomics provides a deeper understanding of key cellular processes occurring in the investigated tissues. In this work, we present for the first time insight into proteomics of the midgut of I. ricinus nymph. Label-free quantitative proteomics was used to elucidate changes during blood meal and development in I. ricinus. A total of 1 534 I. ricinus-specific proteins were identified, with only a few host proteins detected. In addition, the proteins involved in the specific physiological processes of the tick were studied in detail to gain better insight into the ontogeny of the midgut of the nymph.
Project description:In Europe, ticks are the most important vectors of diseases threatening humans, livestock, wildlife and companion animals. Nevertheless, genomic sequence information and functional annotation of proteins of the most important European tick, Ixodes ricinus, is limited. Here we present the first analysis of the I. ricinus genome and of the transcriptome of the unfed I. ricinus midgut. We combined and integrated data from genome, transcriptome and proteome. The de novo assembly of 1 billion paired-end sequences identified 6,415 putative genes providing an unprecedented insight into the I. ricinus genome. Mapping of our midgut mRNA reads to the assembled contigs let us estimate to cover around two third of the unique genomic sequences. In addition, more than 10,000 transcripts from naïve midgut were annotated functionally and/or locally. By combining the alignment-based with a motif-search based annotation approach, we could double the number of annotations throughout all groups without shifting the dataset. Moreover, 1,175 proteins expressed in the naïve midgut were identified by mass spectrometry confirming the high completeness of our transcriptome database, and 608 were significantly annotated for function and/or localization. This multiple-omics study vastly extends the publicly available DNA, RNA and protein databases for I. ricinus and ticks in general.
Project description:In most mosquito species, the females require a blood-feeding for complete egg development. However, in Toxorhynchites mosquitoes, the eggs develop without blood-feeding, and both females and males exclusively feed on sugary diets. The midgut is a well-understood organ in blood-feeding mosquitoes, but little is known about it in non-blood-feeding ones. In the present study, the detailed morphology of the midgut of Toxorhynchites theobaldi were investigated using histochemical and ultrastructural methods. The midgut of female and male T. theobaldi adults consists of a long, slender anterior midgut (AMG), and a short, dilated posterior midgut (PMG). The AMG is subdivided into AMG1 (short, with folds) and AMG2 (long, without folds). Nerve branches and enteroendocrine cells are present in AMG and PMG, respectively. Compared with the PMG of blood-feeding female mosquitoes, the PMG of T. theobaldi is smaller; however, in both mosquitoes, PMG seems be the main region of food digestion and absorption, and protein secretion. The epithelial folds present in the AMG of T. theobaldi have not been reported in other mosquitoes; however, the midgut muscle organization and endocrine control of the digestion process are conserved in both T. theobaldi and blood-feeding mosquitoes.
Project description:To allow estimation of the complexity of the antennal transcriptome between sexes as well as in comparison with a non-antennal tissue, microarrays were designed based on an assembly of new 454 sequence data from the antenna and publicly available data including 454 data from the larval midgut. The microarrays were hybridized with samples generated from the repsecitve tissues from 3 (antenna) and 5 (midgut) animals per sample, with four independent samples per sex (antenna) and tissue (midgut).