All authors have read and approved the final manuscript.”
“Background An increasing set of data is shedding light on the role of microorganisms that have co-evolved with their hosts, including #AZD1480 ic50 randurls[1|1|,|CHEM1|]# humans [3]. They illustrate the high diversity of endosymbiotic forms among living organisms. Moreover the evidence of gene transfer between bacterial cells or viruses and eukaryotic cells supports the theory of symbiotic relationships as a major force driving evolution [4] and as a source of phenotypic complexity [5]. Multiple new symbionts are regularly discovered in the same host, which

can compete or cooperate [3, 6]. Normally, they play a role in host nutrition; defence against pathogens remains an underappreciated benefit of such associations,

both in invertebrates and vertebrates [7, 8]. Social insects are particularly concerned as they are highly susceptible to infectious diseases, due to their lifestyle, and have evolved several associations with microorganisms [9]. Endosymbionts are very common among insects, especially in those sucking plant sap, feeding on vertebrate blood for their entire life span, and those that eat wood and keratin. As they are all strict specialists in nourishment, it is assumed that endosymbionts play a role in providing complementary elements absent from these restricted diets. Camponotus genus, carpenter ants, have Bcl-2 inhibitor established an association with intracellular endosymbionts Blochmannia, a taxon of γ-Proteobacteria, found in all Camponotus species studied hitherto Montelukast Sodium [10]. The bacteria live

within specialized cells, the bacteriocytes. The function of the endosymbionts is not fully elucidated but their role as dietary complement suppliers has been pointed out after the genome sequence analysis of two Blochmannia species. The bacteria is probably able to supply nitrogen and sulphur compounds to the host [11–13]. Moreover, bacteria elimination using antibiotic treatment is deleterious and chemically defined diets can complement bacteria suppression [2, 14] demonstrating the necessary nutritional role of bacteria. However, the presence of Blochmannia in omnivorous Camponotus species suggests that bacteria may also have other functions beneficial to the ants. Some studies have suggested that Blochmannia may play a more important role during the colony founding phase and growth rather than in adult worker maintenance [15] or may play a role in pheromone production [16]. Microbes that forms chronic infections in a host lineage may evolve to promote host survival or benefits to its host, as this will help to maintain its immediate ecological resource [17]. In this context, secondary endosymbionts can provide hosts with defences against parasites, beyond nutritional advantages [18, 19]. So far, no similar example with primary endosymbionts has been reported.