Ticks are obligate hematophagous arthropods that transmit a wide range of pathogens to humans as well as wild and domestic animals. They also harbor a non-pathogenic microbiota, although our previous study has shown that the diverse bacterial microbiome in the midgut of Ixodes ricinus is quantitatively poor and lacks a core. In artificial infections by capillary feeding of ticks with two model bacteria (Gram-positive Micrococcus luteus and Gram-negative Pantoea sp.), rapid clearance of these microbes from the midgut was observed, indicating the presence of active immune mechanisms in this organ. In the current study, RNA-seq analysis was performed on the midgut of I. ricinus females inoculated with either M. luteus or Pantoea sp. or with sterile water as a control. While no immune-related transcripts were upregulated by microbial inoculation compared to that of the sterile control, capillary feeding itself triggered dramatic transcriptional changes in the tick midgut. Manual curation of the transcriptome from the midgut of unfed I. ricinus females, complemented by the proteomic analysis, revealed the presence of several constitutively expressed putative antimicrobial peptides (AMPs) that are independent of microbial stimulation and are referred to here as 'guard' AMPs. These included two types of midgut-specific defensins, two different domesticated amidase effector 2 (Dae2), microplusin/ricinusin-related molecules, two lysozymes, and two gamma interferon-inducible lysosomal thiol reductases (GILTs). The in vitro antimicrobial activity assays of two synthetic mature defensins, defensin 1 and defensin 8, confirmed their specificity against Gram-positive bacteria showing exceptional potency to inhibit the growth of M. luteus at nanomolar concentrations. The antimicrobial activity of midgut defensins is likely part of a multicomponent system responsible for the rapid clearance of bacteria in the tick midgut. Further studies are needed to evaluate the role of other identified 'guard' AMPs in controlling microorganisms entering the tick midgut.

• Klíčová slova
• Ixodes, Micrococcus luteus, antimicrobial peptide, defensin, immune system, midgut microbiome, tick,
• MeSH
• antimikrobiální peptidy metabolismus   MeSH
• gastrointestinální trakt mikrobiologie   imunologie   MeSH
• klíště * mikrobiologie   imunologie   MeSH
• Micrococcus luteus imunologie   MeSH
• proteomika MeSH
• stanovení celkové genové exprese MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antimikrobiální peptidy MeSH

Ticks are hematophagous arachnids transmitting a wide variety of pathogens including viruses, bacteria, and protozoans to their vertebrate hosts. The tick vector competence has to be intimately linked to the ability of transmitted pathogens to evade tick defense mechanisms encountered on their route through the tick body comprising midgut, hemolymph, salivary glands or ovaries. Tick innate immunity is, like in other invertebrates, based on an orchestrated action of humoral and cellular immune responses. The direct antimicrobial defense in ticks is accomplished by a variety of small molecules such as defensins, lysozymes or by tick-specific antimicrobial compounds such as microplusin/hebraein or 5.3-kDa family proteins. Phagocytosis of the invading microbes by tick hemocytes is likely mediated by the primordial complement-like system composed of thioester-containing proteins, fibrinogen-related lectins and convertase-like factors. Moreover, an important role in survival of the ingested microbes seems to be played by host proteins and redox balance maintenance in the tick midgut. Here, we summarize recent knowledge about the major components of tick immune system and focus on their interaction with the relevant tick-transmitted pathogens, represented by spirochetes (Borrelia), rickettsiae (Anaplasma), and protozoans (Babesia). Availability of the tick genomic database and feasibility of functional genomics based on RNA interference greatly contribute to the understanding of molecular and cellular interplay at the tick-pathogen interface and may provide new targets for blocking the transmission of tick pathogens.

• Klíčová slova
• Anaplasma, Babesia, Borrelia, antimicrobial peptides, innate immunity, phagocytosis, tick, tick-borne diseases,
• MeSH
• Anaplasma imunologie   patogenita   MeSH
• arachnida jako vektory imunologie   mikrobiologie   parazitologie   MeSH
• Babesia imunologie   patogenita   MeSH
• Borrelia imunologie   patogenita   MeSH
• interakce hostitele a patogenu * MeSH
• klíšťata imunologie   mikrobiologie   parazitologie   MeSH
• přirozená imunita * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Isolation and separation of specific molecules is used in almost all areas of biosciences and biotechnology. Diverse procedures can be used to achieve this goal. Recently, increased attention has been paid to the development and application of magnetic separation techniques, which employ small magnetic particles. The purpose of this review paper is to summarize various methodologies, strategies and materials which can be used for the isolation and purification of target proteins and peptides with the help of magnetic field. An extensive list of realised purification procedures documents the efficiency of magnetic separation techniques.

• Publikační typ
• časopisecké články MeSH