Acaricides and fungicides such as cumaphos and prochloraz respectively are not intrinsically highly toxic to bees but their action in combination might lead to higher honey bee sensitivity or mortality. In the present study, we investigated the molecular immune response of honey bee workers at different developmental stages (prepupa, white-eyed pupa, adult) exposed to the acaricide coumaphos and the fungicide prochloraz individually and in combination. Expression of 17 immune-related genes was examined by quantitative RT-PCR. In treated prepupae downregulation of most immune-related genes was observed in all treatments, while in adults upregulation of most of the genes was recorded. Our study shows for the first time that negative impacts of prochloraz and a combination of coumaphos and prochloraz differ among the different developmental stages of honey bees. The main effect of the xenobiotic combination was found to be upregulation of the antimicrobial peptide genes abaecin and defensin-1 in adult honey bees. Changes in immune-related gene expression could result in depressed immunity of honey bees and their increased susceptibility to various pathogens.
COBISS.SI-ID: 3642248
In this study, the effects of neonicotinoid thiametoxam on honeybees Apis mellifera carnica previously infested by Varroa destructor mites were analyzed at the molecular level. One week before the experiments were undertaken four honeybee colonies without a queen were established. Just before the start of the experiments unsealed honeybee broods originating from the same honeybee colony to reduce genotypic variability were introduced. Two groups of Varroa mite infested brood were exposed to mites for 10 days. Afterwards all colonies were fed with 100 g protein cake, provided daily for the bees. One infested and one non infested colony received protein cake with thiametoxam (10g/kg). After 10 days exposure to thiametoxam, samples of adult worker honeybees were collected. Total RNA was extracted from 12 bees/group and complementary DNA (cDNA) was synthesized. Expression of 8 detoxification, 2 developmental, 17 immune related and 5 apoptosis related genes were analyzed by real-time PCR.
COBISS.SI-ID: 3838856
We aim to establish a permanent honeybee cell lines for standardized in vitro testing of the effects of xenobiotics and pathogens, which would enable learning and understanding the mechanisms present in vivo. The first step was the preparation of primary cell lines. Here we describe methods that are effective for maintaining various honeybee cells in in vitro conditions. The preparation of cells from different honeybee Apis mellifera carnica developmental stages and the optimization of growth conditions and media for different cell types, including supplements were standardized. Multiple bee cell cultures were produced using bee eggs, larvae, pupae, queen bee ovaries, brains and hypopharyngeal glands as a starting material. Only cells from eggs and pupae were used for further tests. Supplemented L-15 media was found to support long-term growth of eggs while modified WH2 media was established for long-term cultivation of pupae cells. The cells were successfully cultured for up to 6 months and the bee origin of the cells was confirmed using PCR specific primers. Multiple cell phenotypes were observed including free-floating small suspension cells, neuron-like monolayers and cells with multiple nuclei. Cells obtained from pupae were successfully cryopreserved. After thawing their viability was estimated and was always higher than 85 %. For this purpose trypan blue and propidium iodide were used, the latter being more appropriate.
COBISS.SI-ID: 3838600
The Carniolan honey bee, Apis mellifera carnica, is Slovenian autochthonous breed. In recent years, Slovenia, similarly to the rest of the Europe, recorded 15-35% annual loss of bee colonies due to mortality of bees. One of the possible reasons for this could be the exposure of bees to residues of insecticides, acaricides, herbicides and fungicides, which have been found in honeybees and hive products. Acaricides are applied by beekeepers to control ectoparasitic mite Varroa destructor, the most serious pest of honeybee colonies in Europe, whereas the most abundant and common agricultural chemicals found in honeybee are fungicides, which may enter the bee and hive products when applied to nearby flowering crop and fruit plants. Acaricides and fungicides are not highly toxic to bees alone, but they may act in combination and lead to higher honeybee mortality. In our study we investigated the molecular response of different development stages of honeybee workers (larvae, pupae, adult) exposed to a combination of acaricide kumaphos and fungicide procloraz per os. We examined the expression of several genes involved in immune response, detoxification and development by quantitative RT-PCR. We observed that combination of acaricide and fungicide leads to a synergistic effect on several of the immunity-related, detoxifying and development genes. We also found that the kumaphos and procloraz, solitarily or in combination, have important impact on gene expression and that the impact is different in different development stages of honeybee worker.
COBISS.SI-ID: 3453576