Ecologically Appropriate Xenobiotics Induce Cytochrome P450s in Apis mellifera

BACKGROUND: Honey bees are exposed to phytochemicals through the nectar, pollen and propolis consumed to sustain the colony. They may also encounter mycotoxins produced by Aspergillus fungi infesting pollen in beebread. Moreover, bees are exposed to agricultural pesticides, particularly in-hive acaricides used against the parasite Varroa destructor. They cope with these and other xenobiotics primarily through enzymatic detoxificative processes, but the regulation of detoxificative enzymes in honey bees remains largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: We used several approaches to ascertain effects of dietary toxins on bee susceptibility to synthetic and natural xenobiotics, including the acaricide tau-fluvalinate, the agricultural pesticide imidacloprid, and the naturally occurring mycotoxin aflatoxin. We administered potential inducers of cytochrome P450 enzymes, the principal biochemical system for Phase 1 detoxification in insects, to investigate how detoxification is regulated. The drug phenobarbital induces P450s in many insects, yet feeding bees with phenobarbital had no effect on the toxicity of tau-fluvalinate, a pesticide known to be detoxified by bee P450s. Similarly, no P450 induction, as measured by tau-fluvalinate tolerance, occurred in bees fed xanthotoxin, salicylic acid, or indole-3-carbinol, all of which induce P450s in other insects. Only quercetin, a common pollen and honey constituent, reduced tau-fluvalinate toxicity. In microarray comparisons no change in detoxificative gene expression was detected in phenobarbital-treated bees. However, northern blot analyses of guts of bees fed extracts of honey, pollen and propolis showed elevated expression of three CYP6AS P450 genes. Diet did not influence tau-fluvalinate or imidacloprid toxicity in bioassays; however, aflatoxin toxicity was higher in bees consuming sucrose or high-fructose corn syrup than in bees consuming honey. CONCLUSIONS/SIGNIFICANCE: These results suggest that regulation of honey bee P450s is tuned to chemicals occurring naturally in the hive environment and that, in terms of toxicological capacity, a diet of sugar is not equivalent to a diet of honey

<i>Apis mellifera</i> CYP6AS family P450s and their gene expression following feeding on honey, pollen or propolis extract.

<p>Expression of selected P450 genes, as measured by northern blot, in guts of bees fed five g candy containing only sucrose or sucrose plus extract from the given quantity of honey, pollen or propolis. The neighbor-joining tree is rooted with <i>Homo sapiens</i> CYP3A4 and was created using CLUSTALW <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031051#pone.0031051-Thompson1" target="_blank">[88]</a> alignment and PHYLIP <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031051#pone.0031051-Felsenstein1" target="_blank">[89]</a> with 1000 bootstrap replicates. Branches with greater than 50% bootstrap support are indicated with an asterisk. Branch length in the final tree was corrected for multiple substitutions with TREE-PUZZLE <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031051#pone.0031051-Schmidt1" target="_blank">[90]</a>.</p

Relative validity and reproducibility of a food frequency questionnaire used in pregnant women from a rural area of China.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageFood frequency questionnaires are relatively inexpensive, easy and quick to administer, but the construction of a food frequency questionnaire that can capture Chinese food habits is challenging given the diverse lifestyle and eating habits in different parts of the country. The aim of this study was to assess the validity and reproducibility of a self-administered food frequency questionnaire against a 3-day dietary recall in a rural region of western China.Prospective cohort study.Chinese maternal and child healthcare hospital.A total of 168 healthy pregnant women.Pregnant women completed a food frequency questionnaire at 16-24 weeks gestation, and again at 29-31 weeks; during weeks 26-27 they completed a 3-day dietary recall.In general, mean intake was higher when assessed with food frequency questionnaires compared with dietary recall. Spearman and intra-class correlation coefficients between the two food frequency questionnaires ranged from 0.31 to 0.69 and from 0.27 to 0.79, respectively. For the second food frequency questionnaire and the dietary recall, the crude and de-attenuated Spearman correlations ranged from 0.12 to 0.55 and 0.14 to 0.58, respectively. The correlation both between the two food frequency questionnaires and between the second food frequency questionnaire and the dietary recall decreased after adjustment for energy. Ranking women, 31-57% and 1-8% were classified into the same and the opposite quartile, respectively, by both food frequency questionnaires; 30-45% and 1-11% were classified into the same and the opposite quartile respectively for the second food frequency questionnaire and dietary recall.The food frequency questionnaire showed good reproducibility and correlations with dietary recall; it is useful for ranking study participants according to dietary intake, which is of great importance to future etiological studies in this cohort.March of Dimes 6-FY01-317 Danish Council for Strategic Research 09-067124 Nutricia Research Foundation 2013-4

Median survival times for <i>Apis mellifera</i> fed various diets with and without aflatoxin B1 (AB1).

<p>Aflatoxin B1 was applied at 20 µg/g candy in 0.1% dimethyl sulfoxide (DMSO). A DMSO control was applied to diets of pure sucrose “bee candy”, or candy made from equal parts honey and sucrose or high fructose corn syrup (HFCS) and sucrose.</p

Toxicity of pesticides to <i>Apis mellifera</i> in the presence and absence of P450 inducers.

<p>Toxicity bioassays for the pyrethroid pesticides tau-fluvalinate and lambda-cyhalothrin, the organochlorine aldrin, and its bioactivated P450 metabolite dieldrin, using 3-day-old bees fed sucrose “bee candy” or candy with phenobarbital (5 mg/g candy), xanthotoxin (1 mg/g), quercetin (10 mg/g), salicylic acid (2.5 mg/g) or indole-3-carbinol (1 mg/g) added. N = total number of bees included in bioassay, LD₅₀ = Lethal Dose 50%, as calculated by probit model, 95%CI = 95% confidence interval for the LD₅₀ (treatments with non-overlapping 95% confidence intervals are considered significantly different) , slope = slope of the log-probit line, intercept = intercept of the log-probit line, SE = standard error, chi square = statistical test for the probit model, if significant then correction for heterogeneity using Fieller's method was applied, df = degrees of freedom for the chi square test.</p

Dual Functional Ultrasensitive Point-of-Care Clinical Diagnosis Using Metal–Organic Frameworks-Based Immunobeads

Sepsis is an acute systemic infectious syndrome with high fatality. Fast and accurate diagnosis, monitoring, and medication of sepsis are essential. We exploited the fluorescent metal-AIEgen frameworks (MAFs) and demonstrated the dual functions of protein detection and bacteria identification: (i) ultrasensitive point-of-care (POC) detection of sepsis biomarkers (100 times enhanced sensitivity); (ii) rapid POC identification of Gram-negative/positive bacteria (selective aggregation within 20 min). Fluorescent lateral flow immunoassays (LFAs) are convenient and inexpensive for POC tests. MAFs possess a large surface area, excellent photostability, high quantum yield (∼80%), and multiple active sites serving as protein binding domains for ultrasensitive detection of sepsis biomarkers (IL-6/PCT) on LFAs. The limit of detection (LOD) for IL-6/PCT is 0.252/0.333 pg/mL. Rapid appraisal of infectious bacteria is vital to guide the use of medicines. The dual-functional fluorescent MAFs have great potential in POC tests for the clinical diagnosis of bacterial infections