This is initiated by alarm signals [4] and [3] and a chemotactic peptide which contributes to plasmatocyte migration and hemocyte aggregation [48]. The plasmatocytes spread laterally to accommodate expanding nodules [59] and [62].

In conclusion, we demonstrate cholera toxin modulates the adhesive abilities of hemocytes through a cAMP-independent mechanism, B-subunits being the main activating moiety. RGD-dependent microaggregation, formation of nodules in vivo and bacterial removal from the hemolymph is influenced by cholera toxin suggesting the HSP assay toxin, likely by CTB, stimulates hemocyte mobility and the nodulation response. This study was supported by a grant from the Natural Science and Engineering Research Council of Canada to GBD and a grant from the Canadian Institutions of Health Research to CAM. “
“Invertebrate animals can be found in almost every habitat in the world. Because many invertebrates live in environments in which microorganisms thrive, their widespread distribution and survival are primarily due to successful defences that efficiently recognise and combat potentially harmful microorganisms [37]. Invertebrates only possess innate immunity, which is considered to be an ancient defence mechanism [16]. One characteristic of innate immunity is the production of antimicrobial substances, which are often peptides

or polypeptides [12]. Several of these antimicrobial peptides (AMPs) have been recognised as important components of the nonspecific host defence or innate immune system in a variety of organisms and have been isolated and characterised R428 price from plants and animals, including insects, molluscs, crustaceans, amphibians, birds, fish, mammals, and humans [2], [17], [3] and [11]. Several antimicrobial peptides were isolated from SPTLC1 the venom and haemolymph of venomous arthropods such as scorpions and spiders [22]. The haemolymph

of invertebrates are the main source of antimicrobial peptides [14]. The first biochemical study of an antimicrobial peptide in arachnids demonstrated the presence of an antibacterial peptide in the haemolymph of the scorpion species Leiurus quinquestriatus [5] and Androctonus australis [8]. Gomesin was the first antimicrobial peptide isolated from spider blood cells [34]. Other antimicrobial peptides were found in the plasma of shrimp [6], freshwater crayfish [24], the plasma of the tarantula spider Acanthoscurria gomesiana, named theraphosinin [34], and crude haemolymph of Agelena labyrinthica [46]. These peptides are typically relatively short, positively charged (cationic), and amphiphilic [19] and [40] and generally interact with the outer membranes of microorganisms due to their negative charge [20]. Compared to cationic AMPs, much less is known about how anionic AMPs work [39], [36] and [13].