BackgroundGenetic improvement of honey bees is more difficult compared to other livestock, due to the very different reproductive behavior. Estimation of breeding values requires specific adjustment and the use of sires in the pedigree is only possible when mating of queens and drones is strictly controlled. In the breeding program of the National Registry for Italian Queen Breeders and Bee Producers the paternal contribution is mostly unknown. As stronger modeling may compensate for the lack of pedigree information, we tested two models that differed in the way the direct and maternal effects were considered. The two models were tested using 4003 records for honey yield, defensive and swarming behaviors of Italian honey bee queens produced between 2002 and 2014. The first model accounted for the direct genetic effect of worker bees and the genetic maternal effect of the queen, whereas model 2 considered the direct genetic effect of the queen without maternal effect. The analyses were performed by linear (honey production) and threshold (defensive and swarming behavior) single-trait models; estimated genetic correlations among traits were obtained by a three-trait linear-threshold model.ResultsFor all traits, the highest predictability (correlation between breeding values estimated with and without performance records) was obtained with model 2, where direct genetic effect of queens was considered. With this model, heritability estimates were 0.26 for honey yield, 0.36 for defensive behavior, and 0.34 for swarming behavior. Multi-trait estimation resulted in similar or higher heritability estimates for all traits. A low, positive genetic correlation (0.19) was found between honey yield and defensive behavior, whereas the genetic correlation between honey yield and swarming behavior was moderate (0.41). A strong, positive genetic correlation was found between defensive and swarming behaviors (0.62). Predictability for multi-trait evaluations was higher for honey yield (0.46) and defensive behavior (0.30) but almost identical for swarming behavior (0.45) compared to corresponding single-trait predictability.ConclusionsMulti-trait evaluation using a model that accounts for the direct genetic effect of queen was the best approach for breeding value estimation of Italian honey bees. The results suggest a new direction for selection of linear and categorical traits in breeding programs where drone origin is unknown.
The composition of the volatile fraction of Trifolium pratense L. ssp. nivale (Sieber) Asch. et Gr. from the southwestern Alps was investigated. Fresh aerial parts were collected in the summer at three different growth stages, namely vegetative, flowering and fruiting. The oils obtained by steam-distillation accounted for 0.006 to 0.011% of the fresh plant material and their composition was determined by GC/FID and GC/MS. Several classes of compounds were found, with a predominance of alcohols in all phases, followed by aldehydes, hydrocarbons, terpenes, phenolics, ketones, acids and esters. The oil composition varied both in quantity and quality; the most abundant compounds were oct-1-en-3-ol and phenylacetaldehyde in the vegetative and flowering phases, and phenylacetaldehyde and 2-phenylethanol in the fruiting phase. The essential oils obtained were tested for activity against two major bee pests, i.e. Paenibacillus larvae and Melissococcus plutonius, and against a reference bacterial species, Bacillus subtilis.
Orotic acid (OA) is an anabolic intermediate in pyrimidine biosynthesis that originates from carbamyl phosphate. It is present only in trace amount in normal urine, but its excretion increases during pregnancy, drug treatment or because of metabolic block in the urea cycle. Several techniques have been used to measure OA. The widelyused colorimetric method is simple and quite rapid, but suffers from interfering compounds that, if not removed (Harris and Oberholzer 1980) reduce the accuracy of the assay. Because clinicians more and more often require both urinary orotic and organic acid determination, we developed a new stable isotope dilution assay for OA using the same processed urine as for organic acid analysis.Urine samples from patients and controls corresponding to 0.5 mg of creatinine were mixed with 50nmol [15Nz]orotic acid. Organic acids were isolated by solvent extraction according to DiDonato et al (1986) except that after acidification and saltsaturation with NaC1 samples were extracted once with an equal volume of tetrahydrofuran (THF) and twice, respectively with ethyl acetate and diethyl ether. Derivatization was performed with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). A silylated sample aliquot was injected into a Perkin Elmer model 8420 gas chromatograph equipped with a 30 m SPB-20, 0.25 mm ID fused capillary column and interfaced with a Perkin Elmer Ion Trap Detector. The electron impact ionization of the tri-TMS derivative of OA gave two ions with high relative intensity that were
The composition of the volatile fraction of Malva sylvestris var. mauritiana (L.) Boiss. (Malvaceae) was investigated. This plant species was cultivated in the southeastern Alps as an ingredient for herbal teas and infusions. Flowers and leaves were collected at the end of the summer season and separately steamdistilled to obtain two volatile oils, the yields of which were 0.019% for leaves and 0.012% for flowers. After GC-FID and GC-MS analyses, the two oils revealed differences in the nature and especially in the proportion of their components, which were aldehydes, alcohols, phenolics, esters, hydrocarbons and acids. Eugenol was the single most abundant compound in the leaves, totalling 46.7% of the total oil, followed by phytol with 34.4%. Flowers showed a predominance of hydrocarbons, among which the anteiso branched-chain saturated hydrocarbon, 3-methyl tricosane, was the most abundant compound, accounting for 14.9% of the total volatiles. Eugenol ranked second with 10.3%, followed by the two linear-chain saturated hydrocarbons pentacosane and tricosane forming 8.2 and 7.7% of the total oil, respectively. The occurrence and the relative abundance of compounds from various chemical classes such as phenolics, hydrocarbons and aromatic aldehydes and alcohols are discussed, together with some of their ecological implications. The obtained volatile oils were than tested against two major honeybee (Apis mellifera) pathogens, namely Paenibacillus larvae and Melissococcus plutonius, the causative agents of the American and the European foulbrood, respectively.
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