Are ticks venomous animals?

[Introduction]: As an ecological adaptation venoms have evolved independently in several species of Metazoa. As haematophagous arthropods ticks are mainly considered as ectoparasites due to directly feeding on the skin of animal hosts. Ticks are of major importance since they serve as vectors for several diseases affecting humans and livestock animals. Ticks are rarely considered as venomous animals despite that tick saliva contains several protein families present in venomous taxa and that many Ixodida genera can induce paralysis and other types of toxicoses. Tick saliva was previously proposed as a special kind of venom since tick venom is used for blood feeding that counteracts host defense mechanisms. As a result, the present study provides evidence to reconsider the venomous properties of tick saliva. [Results]: Based on our extensive literature mining and in silico research, we demonstrate that ticks share several similarities with other venomous taxa. Many tick salivary protein families and their previously described functions are homologous to proteins found in scorpion, spider, snake, platypus and bee venoms. This infers that there is a structural and functional convergence between several molecular components in tick saliva and the venoms from other recognized venomous taxa. We also highlight the fact that the immune response against tick saliva and venoms (from recognized venomous taxa) are both dominated by an allergic immunity background. Furthermore, by comparing the major molecular components of human saliva, as an example of a non-venomous animal, with that of ticks we find evidence that ticks resemble more venomous than non-venomous animals. Finally, we introduce our considerations regarding the evolution of venoms in Arachnida. [Conclusions]: Taking into account the composition of tick saliva, the venomous functions that ticks have while interacting with their hosts, and the distinguishable differences between human (non-venomous) and tick salivary proteins, we consider that ticks should be referred to as venomous ectoparasites.JJV was sponsored by project CZ.1.07/2.3.00/30.0032, co-financed by the European Social Fund and the state budget of the Czech Republic. ACC was supported by a grant from the Ministère de l’Education Supérieure et de la Recherche of France.Peer Reviewe

Complete genome sequence of Ehrlichia mineirensis, a novel organism closely related to Ehrlichia canis with a new host association

This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license.-- et al.We report here the complete genome sequencing of Ehrlichia mineirensis, an Ehrlichia organism that was isolated from the hemolymph of Rhipicephalus microplus¿engorged females. E. mineirensis is the best characterized Ehrlichia isolate from a novel cattle-related clade closely related to the monocytotropic pathogen E. canis.This research was supported by Spanish National Research Program grant BFU2011-23896 and by EU FP7 ANTIGONE project number 278976. R.T. and M.M. were partially funded by Spanish Ministerio de Ciencia e Innovacion grant IPT-2011-0735-010000. A.C.C. was supported by a grant from the Ministère de l’Education Supérieure et de la Recherche of France.Peer Reviewe

Resistance of tick gut microbiome to anti-tick vaccines, pathogen infection and antimicrobial peptides

Ixodes scapularis ticks harbor microbial communities including pathogenic and non-pathogenic microbes. Pathogen infection increases the expression of several tick gut proteins, which disturb the tick gut microbiota and impact bacterial biofilm formation. Anaplasma phagocytophilum induces ticks to express I. scapularis antifreeze glycoprotein (IAFGP), a protein with antimicrobial activity, while Borrelia burgdorferi induces the expression of PIXR. Here, we tested the resistance of I. scapularis microbiome to A. phagocytophilum infection, antimicrobial peptide IAFGP, and anti-tick immunity specific to PIXR. We demonstrate that A. phagocytophilum infection and IAFGP affect the taxonomic composition and taxa co-occurrence networks, but had limited impact on the functional traits of tick microbiome. In contrast, anti-tick immunity disturbed the taxonomic composition and the functional profile of tick microbiome, by increasing both the taxonomic and pathways diversity. Mechanistically, we show that anti-tick immunity increases the representation and importance of the polysaccharide biosynthesis pathways involved in biofilm formation, while these pathways are under-represented in the microbiome of ticks infected by A. phagocytophilum or exposed to IAFGP. These analyses revealed that tick microbiota is highly sensitive to anti-tick immunity, while it is less sensitive to pathogen infection and antimicrobial peptides. Results suggest that biofilm formation may be a defensive response of tick microbiome to anti-tick immunity

Cancer research meets tick vectors for infectious diseases

Comment.Peer Reviewe

The glycoprotein TRP36 of Ehrlichia sp. UFMG-EV and related cattle pathogen Ehrlichia sp. UFMT-BV evolved from a highly variable clade of E. canis under adaptive diversifying selection

[Background]: A new species of Ehrlichia, phylogenetically distant from E. ruminantium, was found in 2010 infecting cattle in Canada. In 2012 and 2013, we reported the in vitro propagation, molecular and ultrastructural characterization of Ehrlichia sp. UFMG-EV (E. mineirensis), a new species of Ehrlichia isolated from the haemolymph of Brazilian Rhipicephalus (Boophilus) microplus ticks. A new organism, named Ehrlichia sp. UFMT-BV, closely related to Ehrlichia sp. UFMG-EV, was recently described in Brazil and after experimental infection it was shown to be pathogenic for cattle. This new emerging clade of cattle Ehrlichia pathogens is closely related to E. canis. The major immunogenic Tandem Repeat Protein (TRP36; also known as gp36) is extensively used to characterize the genetic diversity of E. canis. Homologs of TRP36 were found in both Ehrlichia sp. UFMG-EV and Ehrlichia sp. UFMT-BV. [Findings]: Herein, we characterized the evolution of this new Ehrlichia clade using TRP36 sequences. Our working hypothesis is that Ehrlichia sp. UFMG-EV and related microorganisms evolved from a highly variable E. canis clade. In support of our hypothesis we found that Ehrlichia sp. UFMG-EV and Ehrlichia sp. UFMT-BV TRP36 evolved from a highly divergent and variable clade within E. canis and this clade evolved under episodic diversifying selection with a high proportion of sites under positive selection. [Conclusion]: Our results suggest that Ehrlichia sp. UFMG-EV and Ehrlichia sp. UFMT-BV evolved from a variable clade within E. canis.This research was partially supported by the EU FP7 ANTIGONE project number 278976. JJV was sponsored by project CZ.1.07/2.3.00/30.0032, co-financed by the European Social Fund and the state budget of the Czech Republic. ACC was supported by a grant from the Ministère de l’Education Supérieure et de la Recherche of FrancePeer Reviewe

The good, the bad and the tick

How tick-borne pathogens (TBPs) could help us understand cancer? The diversity of pathogens transmitted by ticks is higher than that of any other known arthropod vector and includes protozoa (e.g., Babesia spp. and Theileria spp.), bacteria (e.g., intracellular Rickettsia spp. and extracellular Borrelia spp.), viruses (e.g., Tick-borne encephalitis (TBE) and Crimean-Congo hemorrhagic fever (CCHF) virus), helminths (e.g., Cercopithifilaria) and, although less known, fungi (e.g., Dermatophilus) (Otranto et al., 2013; Brites-Neto et al., 2015; de la Fuente et al., 2017). TBPs have complex life cycles that involve vertebrate hosts and the ticks. Intracellular TBP infection triggers cellular and molecular responses that change host cell physiology in fundamental ways. Within vertebrate host cells, the apicomplexan parasites Theileria parva and Theileria annulata activate molecular pathways that result in increased production of reactive oxygen species (ROS), cell immortalization, cancer and host death. In contrast, infection by the rickettsia Anaplasma phagocytophilum inhibits apoptosis, block the production of ROS and results in a self-limiting infection that rarely is lethal for the host. Theileria spp. and A. phagocytophilum modulates host cell response by inducing transcriptional reprogramming of their vertebrate host cells, leukocytes. Transcriptional reprogramming is induced by pathogen-encoded effector proteins that modify host epigenetic pathways that affect not only gene transcription but also protein levels

Rural Constructions in the Professional Training of Students from a Principal Integrating Discipline Perspective

Context: The job insertion of students in the Degree of Education Construction in rural constructions, from the perspective of the professional teaching-learning process of the principal integrating discipline, favors their professional training. From this job context, students associate with constructive typologies that identify their cultural identity, history, the direct relation to nature’s agents, and the utilization of local materials that let them work with a prospering and sustainable vision for the conservation and protection of the ecosystem during the process of rural construction. Aim: To provide a rationale of rural constructions as a job context in the professional teaching-learning process through the principal integrating discipline, to students in the Degree of Education Construction. Methods: The essential methods used are analysis-synthesis, induction-deduction, and scientific observation, which provided evidence of insufficiencies in the job training of students in the Degree of Education in Construction in relation to rural constructions, from the perspective of the principal integrating discipline. Results: Labor qualities, and the traits of a Bachelor in Education in Construction, in relation to their performance in rural constructions were presented within the job context of the principal integrating discipline, with a prospering and sustainable vision

Thermostable Keystone bacteria maintain the functional diversity of the Ixodes scapularis microbiome under heat stress

Variations in the composition and diversity of tick microbiome due to high temperatures may influence the hierarchy of community members as a response to environmental change. Modifications in the community structure are hypothesized to drive alterations in the presence and/or abundance of functional pathways in the bacterial metagenome. In this study, this hypothesis was tested by using published 16S rRNA datasets of Ixodes scapularis males incubated at different temperatures (i.e., 4, 20, 30, and 37 degrees C) in a laboratory setting. Changes in community structure and functional profiles in response to temperature shifts were measured using co-occurrence networks and metagenome inference. Results from laboratory-reared ticks were then compared with those of field-collected ticks. The results from laboratory-reared ticks showed that high temperature altered the structure of the microbial community and decreased the number of keystone taxa. Notably, four taxa were identified as keystone in all the temperatures, and the functional diversity of the tick microbiome was contained in the four thermostable keystone their associated bacterial taxa. Three of the thermostable keystone taxa were also found in free-living ticks collected in Massachusetts. Moreover, the comparison of functional profiles of laboratory-reared and field-collected ticks revealed the existence of an important set of metabolic pathways that were common among the different datasets. Similar to the laboratory-reared ticks, the keystone taxa identified in field-collected ticks alongside their consortia (co-occurring taxa) were sufficient to retain the majority of the metabolic pathways in the functional profile. These results suggest that keystone taxa are essential in the stability and the functional resiliency of the tick microbiome under heat stress

Sex-Specific Linkages Between Taxonomic and Functional Profiles of Tick Gut Microbiomes

Ticks transmit the most diverse array of disease agents and harbor one of the most diverse microbial communities. Major progress has been made in the characterization of the taxonomic profiles of tick microbiota. However, the functional profiles of tick microbiome have been comparatively less studied. In this proof of concept we used state-of-the-art functional metagenomics analytical tools to explore previously reported datasets of bacteria found in male and female Ixodes ovatus, Ixodes persulcatus, and Amblyomma variegatum. Results showed that both taxonomic and functional profiles have differences between sexes of the same species. KEGG pathway analysis revealed that male and female of the same species had major differences in the abundance of genes involved in different metabolic pathways including vitamin B, amino acids, carbohydrates, nucleotides, and antibiotics among others. Partial reconstruction of metabolic pathways using KEGG enzymes suggests that tick microbiome form a complex metabolic network that may increase microbial community resilience and adaptability. Linkage analysis between taxonomic and functional profiles showed that among the KEGG enzymes with differential abundance in male and female ticks only 12% were present in single bacterial genera. The rest of these enzymes were found in more than two bacterial genera, and 27% of them were found in five up to ten bacterial genera. Comparison of bacterial genera contributing to the differences in the taxonomic and functional profiles of males and females revealed that while a small group of bacteria has a dual-role, most of the bacteria contribute only to functional or taxonomic differentiation between sexes. Results suggest that the different life styles of male and female ticks exert sex-specific evolutionary pressures that act independently on the phenomes (set of phenotypes) and genomes of bacteria in tick gut microbiota. We conclude that functional redundancy is a fundamental property of male and female tick microbiota and propose that functional metagenomics should be combined with taxonomic profiling of microbiota because both analyses are complementary

Impacto social de la preparación investigativa de los residentes y estudiantes del Programa Nacional de Formación de Medicina General Integral de la Misión Sucre

The article illustrates the social impact achieved with the investigative preparation of a medical resident and five students of the Programa Nacional de Formación de Medicina Integral Comunitaria de la Misión Sucre, that carried out its professional acting and labor practice in the area of health assisted by the Consultorio Médico Popular de la Comunidad de Pariapan en San Juan de los Morros, Guárico of the Republica Bolivariana de Venezuela.El artículo ilustra el impacto social logrado con la preparación investigativa de un médico residente y cinco estudiantes del Programa Nacional de Formación de Medicina Integral Comunitaria de la Misión Sucre, al realizar su desempeño profesional y práctica laboral en el área de salud atendida por el Consultorio Médico Popular de la Comunidad de Pariapan en San Juan de los Morros, estado Guárico de la República Bolivariana de Venezuela