title: Evidence of immunocompetence reduction induced by cadmium exposure in honey bees (Apis mellifera).
abstract: In the last decades a dramatic loss of Apis mellifera hives has been reported in both Europe and USA. Research in this field is oriented towards identifying a synergy of contributing factors, i.e. pathogens, pesticides, habitat loss and pollution to the weakening of the hive. Cadmium (Cd) is a hazardous anthropogenic pollutant whose effects are proving to be increasingly lethal. Among the multiple damages related to Cd contamination, some studies report that it causes immunosuppression in various animal species. The aim of this paper is to determine whether contamination by Cd, may have a similar effect on the honey bees' immunocompetence. Our results, obtained by immune challenge experiments and confirmed by structural and ultrastructural observations show that such metal causes a reduction in immunocompetence in 3 days Cd exposed bees. As further evidence of honey bee response to Cd treatment, Energy Dispersive X-ray Spectroscopy (X-EDS) has revealed the presence of zinc (Zn) in peculiar electron-dense granules in fat body cells. Zn is a characteristic component of metallothioneins (MTs), which are usually synthesized as anti-oxidant and scavenger tools against Cd contamination. Our findings suggest that honey bee colonies may have a weakened immune system in Cd polluted areas, resulting in a decreased ability in dealing with pathogens.
authors.affiliation: Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy. Electronic address: polykretis@cerm.unifi.it.
authors.forename: P
authors.initials: P
authors.lastname: Polykretis
authors.affiliation: Department of Biology, University of Florence, Via La Pira 4, 50121, Florence, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Delfino
authors.affiliation: Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Florence, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Petrocelli
authors.affiliation: Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Florence, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Cervo
authors.affiliation: Department of Biology, University of Florence, Via La Pira 4, 50121, Florence, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Tanteri
authors.affiliation: Department of Biology, University of Florence, Via La Pira 4, 50121, Florence, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Montori
authors.affiliation: Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, Florence, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Perito
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134, Florence, Italy.
authors.forename: J J V
authors.initials: JJV
authors.lastname: Branca
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134, Florence, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Morucci
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla 3, 50134, Florence, Italy. Electronic address: massimo.gulisano@unifi.it.
authors.forename: M
authors.initials: M
authors.lastname: Gulisano
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001516:Bees / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002104:Cadmium / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000009:adverse effects*; D005060:Europe; D007121:Immunocompetence / Q000187:drug effects*; D008668:Metallothionein; D010575:Pesticides; D013312:Stress, Physiological; D014481:United States; D015032:Zinc / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004785:Environmental Pollutants; D010575:Pesticides; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc
keywords: Apis mellifera; Cadmium; Fat bodies; Immunosuppression; Metallothioneins