Cnidarian immunity

Imunosni sustav je ključan za obranu svakog organizma od patogenih organizama, ozljeda i abnormalnih staničnih procesa. Žarnjaci su veoma raznoliko koljeno životinja koje nemaju razvijen stečeni imunitet, ali se oslanjaju na urođeni imunitet i razvili su složene i veoma učinkovite procese obrane i zaštite od štetnih mikroorganizama. Prva linija obrane su receptori prepoznavanja uzorka (PRR) koji imaju mogućnost imunosnog prepoznavanja, a najpoznatiji su TLR receptori, NOD receptori i lektini. Ti proteini aktiviraju imuno-signalni module žarnjaka poput TLR puta i puta aktivacije sinteze melanina te puta komplementa koji su ključni prilikom procesa poput inkapsulacije patogena, razgradnje i zacjeljivanja rana. Krajnje točke ovih signalnih kaskada su imunosni efektori, molekule i proteini čija je glavna zadaća uništavanje patogena. Postoji nekoliko efektorskih odgovora kod žarnjaka, a oni uključuju površinski sloj sluzi, antimikrobne peptide, reaktivne kisikove radikale te cirkulirajuću populaciju amebocita. Bitna komponenta imuniteta žarnjaka je i epitel koji služi kao imunosna prepreka. Epitel je stanište mikrobnim zajednicama i simbiontima koji su također dio imunosnog sustava te su od esencijalne važnosti za zdravlje jedinke. U ovom radu je pobliže opisan imunitet žarnjaka uključujući složene reakcije koje se odvijaju u trenutku kada jedinka dođe u doticaj s patogenom i način na koji dolazi do njihovog izoliranja te uništavanja.The immune system is crucial for every organism's defence against pathogenic organisms, injuries and abnormal cellular processes.. Cnidarians are a very diverse phylum of animals without developed adaptive immunity, but rely on innate immunity and have developed complex and very effective defense and protection mechanisms against harmful microorganisms. The first line of defence present pattern recognition receptors (PRR) essential for immune recognition, and the best known are TLR receptors, NOD receptors and lectins. These proteins activate the immune signaling modules such as the TLR pathway, the melanin synthesis pathway and complement pathway, which are crucial in processes such as pathogen encapsulation, lysis and wound healing. The endpoints of these signaling cascades are immune effectors, molecules and proteins whose main task is to destroy pathogens. There are several effector responses in cnidarians, and they include the mucosal surface layer, antimicrobial peptides, reactive oxygen species and circulating population of amoebocytes. An important component of cnidarian immunity is the epithelium, which serves as an immune barrier. The epithelium is a habitat for microbial communities and symbionts that are considered important part od the immune system and are essential for the health of an individual organism. This thesis describes in more detail the immunity of cnidarians, including the complex reactions initiated upon the contact with the pathogen and the way in which intruders are isolated and destroyed