Antibacterial Immune Competence of Honey Bees (Apis mellifera) Is Adapted to Differen

Discussion in 'Bee News' started by Americasbeekeeper, Jun 25, 2013.

  1. Americasbeekeeper

    Americasbeekeeper New Member

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    Antibacterial Immune Competence of Honey Bees (Apis mellifera) Is Adapted to Different Life Stages and Environmental Risks
    Newly emerged adult worker bees and drones were able to activate efficiently all examined immune reactions. The number of viable bacteria circulating in the haemocoel of infected bees declined rapidly by more than two orders of magnitude within the first 4–6 h post-injection (p.i.), coinciding with the occurrence of melanised nodules. Antimicrobial activity, on the other hand, became detectable only after the initial bacterial clearance.
    http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066415
     
  2. Crofter

    Crofter New Member

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    What I found really interesting is that the pupal stages of bees lose their immune response. It is normally a time of complete isolation in relatively pathogen free surroundings. Varroa mites and their offspring breaks the defence of that system. That is my dumbed down take away from this

    "At the last larval or prepupal stage, bee larvae stretch out and begin to spin a cocoon around themselves. Subsequently, the brood cells are sealed with a wax lid by worker bees [1], [40]. This extraordinary seclusion of honey bee pupae might be one explanation for their loss of an active immune system. The prepupal stage is accomplished by defecation. As a consequence, bee pupae are usually free of intestinal microorganisms that larvae have ingested with their food [74]. This feature might further explain the absence of an active immune system in bee pupae which are neither externally nor internally threatened by microbial infections – until the recent introduction of the Varroa mite. The most deleterious effect of this new honey bee parasite is caused by the reproductive phase of V. destructor within sealed drone and worker brood cells. The mother mite creates a hole in the cuticle of the pupa, sucking out the haemolymph for feeding the offspring [75]. The bee pupa is damaged in a variety of ways that either leads to premature death of the pupa or results in a reduced life-span or an impairment of cognitive abilities of adult worker bees [75], [76]. Being a vector for various honey bee viruses, Varroa mite infestation of the brood might enhance the damaging effect on pupae and adults [41], [75]. Bacteria might as well be transmitted by mites within the brood cell from their former contacts with honey bee workers in the hive and hence, bacterial infections could in fact contribute to the overall damage of pupae because of the absence of defence reactions in the latter. In this context, it should be noted that bacterial colonies have frequently been found on the Varroa feeding sites of honey bee pupae"