The sialotranscriptome of Antricola delacruzi female ticks is compatible with non-hematophagous behavior and an alternative source of food

Abstract

The hosts for Antricola delacruzi ticks are insectivorous, cave-dwelling bats on which only larvae are found. The mouthparts of nymphal and adult A. delacruzi are compatible with scavenging feeding because the hypostome is small and toothless. How a single blood meal of a larva provides energy for several molts as well as for oviposition by females is not known. Adults of A. delacruzi possibly feed upon an unknown food source in bat guano, a substrate on which nymphal and adult stages are always found. Guano produced by insectivorous bats contains twice the amount of protein and 60 times the amount of iron as beef. In addition, bacteria and chitin-rich fungi proliferate on guano. Comparative data on the transcriptome of the salivary glands of A. delacruzi is nonexistent and would help to understand the physiological adaptations of salivary glands that accompany different sources of food as well as the steps taken by the Acari towards haematophagy, believed to have evolved from scavenging dead animals. Annotation of the transcriptome of salivary glands from female instars of A. delacruzi collected on guano categorized 5.7% of the clusters of expressed genes as putative secreted proteins. They included abundantly expressed TIL domain-containing proteins (possible anti-microbials), an abundantly expressed protein similar to a serum amyloid found in the sialotranscriptomes of Ornithodoros spp., a savignygrin, a family of mucin/peritrophin/cuticle-like proteins, antimicrobials and an HIV envelope-like glycoprotein also found in soft ticks. When comparing the transcriptome of A. delacruzi with those of blood-feeding female soft and hard ticks some notable differences were observed; they consisted of the following transcripts over- or under-represented or absent in the sialotranscriptome of A. delacuzi that may reflect its source of food: ferritin, mucins with chitin-binding domains and TIL domain-containing proteins versus lipocalins, basic tail proteins, metalloproteases, glycine-rich proteins and Kunitz protease inhibitors, respectively.

Gut transcriptome analysis on females of Ornithodoros mimon (Acari: Argasidae) and phylogenetic inference of ticks

“…Iron is a substance derived from degradation of the hemoglobin present in the blood meal, which results in compounds that serve as nutrients for ticks to feed on, develop and reproduce . Ferritin is frequently found in the mialome and sialometranscriptome analysis of ticks (ANDERSON et al, 2008;RIBEIRO et al, 2012;KOTSYFAKIS et al, 2015;XU et al, 2016), as well as in the proteome studies (OLEAGA et al, 2015).…”

Animals as Habitats

“…delacruzi are parasitic on bats, but nymphs and adults have reduced mouthparts and don't feed on blood. Instead, they appear to consume the nutrient-rich bat guano on which they spend most of their time, and have salivary glands very different from those of normal blood-feeding ticks (Ribeiro et al 2012 ). Klimov and OConnor ( 2013 ) provide strong evidence that free-living dust mites in the family Pyroglyphidae arose from one or two switches from an obligatory on-host lifestyle, but it is not clear that the diet of the mites changed, as the ancestors of dust mites may also have fed on keratin (albeit on the body of the host rather than in the host's nest).…”

Whole transcriptome analysis of the poultry red mite Dermanyssus gallinae (De Geer, 1778)

“…Besides knowledge on the genetic level, essential data are provided for future research on new perspectives to control this parasitic mite by identifying possible drug targets or vaccine candidates. For instance, drug targets can be discovered by identification of essential and/or invertebrate specific transcripts followed by subsequent in silico prediction of interactions with drug compounds using appropriate databases such as BRENDA (Schomburg et al 2004) or KEGG BRITE (Kanehisa et al 2006). Besides extrapolation from vaccine studies performed with other macroparasites, potential D. gallinae vaccine candidates can be predicted by using bioinformatic tools supporting the identification of proteins which are directly (e.g.…”

“…For ticks, which are closely related to mites, mainly transcriptome studies of specific organs, like the synganglion and associated neurosecretory organs as well as salivary glands or midgut, are available (Alarcon-Chaidez et al 2007;Anderson et al 2008;Bissinger et al 2011;Ribeiro et al 2012). Even though D. gallinae shares anatomical similarities to ticks, for example the intestinal tract (Harrison and Foelix, 1999), considerable differences between ticks and mites are assumed (Cabrera et al 2010).…”